# Question
Title: What is the name of the phenomenon where a person abandons simplifying a complex system upon understanding the system?
What is the name of the phenomenon where a person abandons simplifying a complex system upon understanding the system?

I provide examples of complex systems, so as not to get hung up on a specific domain.

**Example 1**

A new member of a software development team has to work with legacy, seemingly complicated code. Said person feels the need to simplify the code, and upon doing so, familiarises him/herself with the code. This is usually the point at which the new team member abandons the refactoring/rewrite. She thinks "OK, I understand it now. I can carry on with the actual task I set out to do".

Future new members of the software development team will now lose the benefit of this simplification, and will go through the same (arguably wasteful) learning process themselves.

The reason for the simplification could still be entirely valid (e.g. in a software context again: using domain types instead of primitive types; to communicate intent more clearly).

**Example 2**

An electrician who has never been to a particular house is tasked with installing a three-way switch on the staircase. Said electrician sees the wiring and feels the need to rip it all out and start again. He/she starts making mental notes of the wires, their colours, which trip switches the wires are connected to, etc. After a while, the electrician understands the wiring, abandons the plan to rewire the entire house, and now simply installs the three-way switch.

Future electricians who visit the house will lose the benefit of the rewire (simplification) and will go through the same familiarisation process themselves.

# Answer
> 1 votes
The phenomenon may be explained like this :

1. The programmer was given the task to fix a bug on a complicated legacy code he does not understand.
2. The programmer forms a subgoal "Refactor the code", in order to achieve the above goal.
3. In the process of achieveing the subgoal "Refactor the code", he understands what needs to be done to fix the bug. So the refactoring is not a useful goal any more and it is abandoned.

So we have a primary goal of fixing the bug and a secondary goal, formed to serve the primary goal, to refactor the code. When the primary goal is achieved the secondary is no longer relevant.

To promote refactoring you must take actions so that the secondary goal of refactoring becomes also a primary goal, concurrently with other tasks like fixing a bug. For example you may give rewards to programmers that successfully refactor the code or you may change the culture of your team, so that refactoring is considered a social norm, etc.

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Tags: expertise
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title: Are Free Will and Motivation related?

text:
# Question
Title: Are Free Will and Motivation related?
I'm aware of numerous experiments, like Stanford prison experiment, Milgram experiment which indicate that humans can act in ways opposite to their best intentions.

For the purposes of this question, let's define Free Will as ability to act and strive without external coercion. Ability to accomplish my goals and ambitions. In this context Free Will suddenly seems a lot like motivation.

Found these quotes:

> Likewise, compatibilists define free will as freedom to act according to one's determined motives without hindrance from other individuals

This makes me ask - **Is Free Will related or is just another word for a more modern concept of "motivation"?**

# Answer
> 2 votes
To want, to feel, and to think, also known as conation, emotion, and cognition are the three basic categories that psychology is traditionally concerned with. The term *conation* as far as I know is rather outdated (see Winch, 1909), whereas *motivation* is the newer term for the "drive to act".

As usual within psychology, the term "conation" is not used consistently. However, even when motivation and conation are given distinct meanings, the terms are still closely related to each other (e.g. Reitan & Wolfson, 2000).

To sum up, the concept of *(free) will* is a subcategory of motivation/conation whereas sibling categories are interest or desire.

## References

Reitan, R. M., & Wolfson, D. (2000). Conation: A Neglected Aspect of Neuropsychological Functioning. Archives of Clinical Neuropsychology, 15(5), 443–453. https://doi.org/10.1016/S0887-6177(99)00043-8

Winch, W. H. (1909). Conation and Mental Activity. II. The Journal of Philosophy, Psychology and Scientific Methods, 6(19), 505–514. https://doi.org/10.2307/2012061

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Tags: cognitive-psychology, motivation, cognitive-modeling, behavior, free-will
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title: Quantifying the Dunning-Kruger Effect

text:
# Question
Title: Quantifying the Dunning-Kruger Effect
The Dunning-Kruger effect states that people unexperienced in a certain field or subject generally perceive themselves as having greater aptitude than in reality they do. Dunning and Kruger were able to quantify this using test-scores in their original paper, but popular expositions typically generalize this in a way consistent with the following plot:

As a layman, this form is more interesting to me because it is more generally applicable, but it also suffers from some drawbacks:

1. **How should experience/confidence be gauged or measured? Is there a general way to do this which doesn't rely on test scores?**
2. **Suppose experience is measured in hours spent on the subject. Is there an approximate number of hours at which the peak is reached? The minimum? If so what are these numbers?**

If an answer to either (but especially 2) is possible or available, it will help conscientious newcomers to any subject estimate the amount of time needed before trusting a self-evaluation of their competency.

# Answer
**Premise:** I understand that the question is how to gauge (that is, to create a measure) or to assess *expertise* in something.

**Answer 1.**

Some criteria (very loosely translated from Hacker, 2005, pp. 381):

* issue-specific knowledge;
* general knowledge about the topic of expertise combined with problem-solving heuristics ranging across specific issues of this very topic;
* knowledge of ideal courses of action;
* conscious reflectiveness on the adequacy of task execution;
* metacognitive ability (e.g. internalized, automated execution involving also motivation, emotional intelligence etc.);
* ability to solve new kinds of problems related to the topic of expertise.

**Answer 2.**

No, there aren't any general numbers since it is not possible to define them without referring to both a specific topic of expertise and the predisposition of the person aiming to become an expert.

While I am not aware of any research to support this claim empirically, I maintain that a logical argument can suffice: How long will it take the same individual to acquire expertise as a surgeon compared to acquiring expertise at peeling potatoes?

Moreover, the development of confidence over time is closely tied to both the frequency and the quality of feedbacks about ones' success at doing something in the real world (Hacker, 2005).

**Note:** Unfortunately the cited work is written in German. A not as extensive English language replacement for it is Hacker (2003).

## References

Hacker, W. (2003). Action Regulation Theory: A practical tool for the design of modern work processes? European Journal of Work & Organizational Psychology, 12(2), 105. https://doi.org/10.1080/13594320344000075

Hacker, W. (2005). Allgemeine Arbeitspsychologie: psychische Regulation von Wissens-, Denk- und körperlicher Arbeit. Bern: Huber.
> 4 votes

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Tags: social-psychology, perception, personality, experimental-psychology
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title: MRI images upside-down in FSLVIEW

text:
# Question
Title: MRI images upside-down in FSLVIEW
I'm visualizing structural data in FSLVIEW, but the sagittal and coronal planes are both upside-down / not in the conventional orientation, i.e. rotated by 90º and 180º. I understand that this upside-down view is due to the images being displayed in the order that they are stored on disk, but as I need to anatomically define ROIs on my structural, it would be more convenient if the brain were correctly oriented.

Any ideas on how to rotate these two views? The actual orientation labels themselves (S/I, A/P) are correct. Thanks!

# Answer
> 2 votes
Totally out of my league here, but judging from a quick Google search, this seems to be a common problem in FSL. You've said this YouTube video helps, so that's good...but since it uses an applescript, I suppose it requires the Mac OS.

You say Freesurfer's mri\_convert works in Linux using this code:

```
mri_convert
--in_orientation [file's current storage order, e.g. LAS]
--out_orientation [desired storage order]
<in volume>
<out volume>

```

# Answer
> 2 votes
Simply `fslreorient2std` will orient the images as you would expect.

From https://fsl.fmrib.ox.ac.uk/fsl/fslwiki/Orientation%20Explained:

> fslreorient2std - this is a simple tool designed to reorient an image to match the orientation of the standard template images (MNI152) so that they appear "the same way around" in FSLView.

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Tags: neuroscience, neuroimaging, fmri
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# Question
Title: Does creativity decrease when invested in multiple areas?
I'm a math student and I find that coming up with original ideas and being creative is very important in the field. I love math and I'm also a voracious reader and I like to learn about many things including physics, philosophy, history, music, etc. but math is on the top. So I like to think about these areas, however, sometimes I get this worry that because I'm investing my thinking into something other than math that my creative abilities will "run-out" and I won't be able to contribute creative ideas in math . Is there any validity to this idea? I know my question sounds weird, but it's been bugging me especially that I'm not aware of any research regarding this. Thanks

# Answer
> 5 votes
There are two sources of creativity, the within-domain analogies and the between-domain analogies. Within-domain analogies are less original but more easy to apply and use. Between-domain analogies are far more original but usually need a lot of work to apply them in the target domain. (see this book for more info)

> **Within-domain analogies** may be quite effective in making the resulting design solutions more useful, since the sources may be industry standards that are effective and tested. But the resulting solutions are less original.
>
> **Between-domain analogy**. Random between-domain cues have a positive affect on originality.

In the community of innovation T-shaped persons are highly valued. These individuals are very specialized in one area (the vertical line of T) and also have a broad but shallow knowledge of many other disciplines (the horizontal line of T).

> The vertical bar on the T represents the depth of related skills and expertise in a single field, whereas the horizontal bar is the ability to collaborate across disciplines with experts in other areas and to apply knowledge in areas of expertise other than one's own.

You will not "run-out" of creativity, it is simply a matter of resource allocation. You should spend most of your time at your specialized field, but at the same time you must allocate a significant proportion of your time in other fields like physics, philosophy, history, music, engineering, biology or even to more diverse domains like fishing, sports etc. This way you will create a T-shape knowledge which according to the above references, will make you more creative and more usefull.

# Answer
> 0 votes
In order to be creative in some areas, you should be bothered by some problems. It is important to have relevant knowledge because creativity in math is not similar to creativity in art, where rules can be broken. Relevant knowledge is essential also because it offers tools. What is relevant is not always easy to identify. Asking related questions might also be good.

It is important, however, to take breaks in dealing with the questions that bother you. It helps to lose the ties that tie you to specific ways of thinking. Sleeping also contributes because it helps to lose existing ties and build new ties - some of them might be surprising. Dealing with other fields may or may not help directly, depending on how the deep structure of things might be transferred, but the breaks themselves are important, so in general, it is not a bad thing to spread on various different issues, as long as you find the time for the "dry" things.

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Tags: developmental-psychology, creativity
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# Question
Title: Does distraction cause us to skip to the next step in a motor plan?
Often, if one is concentrating too hard on a particular task, it seems as though it's quite easy to skip to the next step of a plan of action. For example, a baseball infielder may attempt a throw to first base before he has fielded the ball cleanly.

Is the intervening (skipped) movement actually removed from the sequence of steps in the existing motor plan, and is this facilitated by one's level of distraction, or do external stimuli cause the original plan to be created with this flaw?

# Answer
> 3 votes
Q: Does distraction cause us to skip to the next step in a motor plan?

A: It depends on the processes in progress, characteristics of the subject and characteristics of the signal to produce interference (based on an orientation reflex that is the beginning of an act of involuntary attention), many factors, mainly:

* Characteristics of the process involved in the distraction (mainly nature of the stimulus but also what relevance it has for the subject).
* The nature of the processes that are being executed in the motor plan (automatic or controlled, these processes differ in practice, memory, difficulty, relectivity, required level of effort, etc.) (processes related to sports can be automated much from training).
* Characteristics of the subject (different capacities of selective attention, etc.).

See: Shiffrin, R. M., & Schneider, W. (1977). Controlled and automatic human information processing. Perceptual learning, automatic attending, and a general theory. Psychological Review, 84, 127-190.

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Tags: performance, motor, attention
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# Question
Title: Why does the summer holiday go so quickly?
Take 6 weeks at school or work and it'll feel like an eternity, If your out with your mates or on holiday, time flies! Why do we feel like this considering everyday contains 24 hours.

# Answer
Please check the answer to this question, Why do some days feel fast and others feel slow?, think that is the answer you are looking for.
> 0 votes

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Tags: time
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title: How do brain zaps occur?

text:
# Question
Title: How do brain zaps occur?
I've recently witnessed someone undergoing brain zaps and subsequent panic attacks after having stopped their SSRI medication and 48 hours partying with heavy boozing and no sleep.

Having reviewed the literature, I'm under the impression that they often occur in stress related situations or serotonin dysregulation (MDMA seems to trigger brain zaps), but I also read isolated people claiming they could voluntarily trigger brain zaps by "tensing up" and voluntary eye movements. These people said they could do that in a context devoid of any anxiety issues. Also a few marginal reports of brain zaps by heavy opiate, LSD, DXM and ketamin users, but who do not seem specific about details.

I'm under the impression that brain zaps can be caused by anxiety, but also that they can trigger violent panic attacks (fight-or-flight response from the brain zaps), but again also that they reportedly occur in the absence of stress.

What is known of what really happens at a cognitive, neural, or psychochemical level during brain zaps? What's the mechanisms? In the absence of hard science about it, what are the most plausible speculations?

# Answer
Here's the only speculation I could find about brain shivers aka brain zaps.

Cortes JA, Radhakrishnan R. A Case of Amelioration of Venlafaxine-Discontinuation “Brain Shivers” With Atomoxetine The Primary Care Companion for CNS Disorders. 2013;15(2):PCC.12l01427. doi:10.4088/PCC.12l01427.

It proposes an explanation related to norepinephrine. Also, it claims that brain shivers or brain zaps are related to Lhermitte's phenomenon. I have mixed feelings about this specific comparison from what I've witnessed.

"These facts point to the possibility that increases in synaptic norepinephrine are due to norepinephrine transporter reversal, akin to dopamine transporter reversal associated with amphetamine. Abrupt withdrawal of venlafaxine would hence result in paradoxical increase in synaptic norepinephrine via efflux through norepinephrine transporter channels, which is normalized by atomoxetine’s norepinephrine transporter blockade."

That would explain brain zaps from stopping tramadol and SNRIs too, by the way: a noradrenergic syndrome.

Anyone has a better or more supported speculation?
> 4 votes

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Tags: neuroscience, perception, cognitive-neuroscience, bias, anxiety
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title: Understanding Melatonin

text:
# Question
Title: Understanding Melatonin
Is my understanding roughly correct?

1. Melatonin is 'generated' in the absence of specific wavelengths of light.
2. It accumulates and is only reduced by sleep, in particular REM sleep.
3. Melatonin and sleepiness have a causal relationship.

# Answer
There is an entry in the Encyclopædia Britannica on Melatonin which gives a run-down on how melatonin is produced and it's use within sleep, regulating reproductive hormones, and helping the immune system.

> In humans, melatonin plays an important role in the regulation of sleep cycles (i.e., circadian rhythm). Its production is influenced by the detection of light and dark by the retina of the eye. For example, the production of melatonin is inhibited when the retina detects light and is stimulated in the absence of light. Special photoreceptor cells in the retina send signals about light status to the suprachiasmatic nucleus (SCN) in the hypothalamus of the brain. These signals are then transmitted to the pineal gland. Melatonin generation by the pineal gland, which peaks during the nighttime hours, induces physiological changes that promote sleep, such as decreased body temperature and respiration rate. During the day, melatonin levels are low because large amounts of light are detected by the retina. Light inhibition of melatonin production is central to stimulating wakefulness in the morning and to maintaining alertness throughout the day.

Therefore, to correct points 1-3 in your question...

1. Melatonin is produced **when the retinas do not pick up any light**.
2. Melatonin **accumulates in the body during sleep** and is **reduced when the retinas pick up light**.
3. Melatonin **regulates sleep cycles** by inducing physiological changes that promote sleep, such as decreased body temperature and respiration rate.

Because melatonin regulates sleep cycles, melatonin has a big role to play in mental wellbeing. Deregulation or misregulation of circadian rhythms can cause mood spectrum disorders, including bipolar disorder (BD), major depressive disorder (MDD), and seasonal affective disorder (SAD). (De Berardis, et al. 2015)

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## Reference

De Berardis, D., Orsolini, L., Serroni, N., Girinelli, G., Iasevoli, F., Tomasetti, C., Mazza, M., Valchera, A., Fornaro, M., Perna, G., Piersanti, M., Di Nicola, M., Cavuto, M., Martinotti, G. & Di Giannantonio, M., 2015. The role of melatonin in mood disorders. *ChronoPhysiology and Therapy*, 5, pp. 65-75
DOI: 10.2147/CPT.S41761
> 3 votes

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Tags: neuroscience, sleep
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# Question
Title: What is the correlation between self-rated and objective measures of intelligence?
In the context of a broader question, someone asked:

> Can the detailed analyses from, say, the Wechsler test, be used to inform decisions significantly better that gut feelings can?

While this question might be closed, I thought a more defined question regarding the correlation between self-rated and objective measures of intelligence would be good to have. I feel as if I've read papers that suggest the correlation is modest (e.g., r = .2 or .3). Presumably, Dunning-Kruger and a bunch of self-serving biases operate. But I could not find any authoritative reference off hand. So my questions:

* What is the correlation between self-rated intelligence and objective measures of intelligence (i.e., full scale IQ scores from well-validated measures)?
* To what extent does the correlation depend on how the self-ratings are obtained?

# Answer
> 6 votes
The term you are looking for is self-assessed intelligence (SAI) (sometimes subjectively-assessed intelligence or self-estimated intelligence). The leaders in this field are Tomas Chamorro-Premuzic and Adrian Furnham. From their book "Personality and Intellectual Competence" (2014):

> Correlations between SAI and psychometric intelligence have been significant and positive, albeit generally modest (r\<.30).

So you are spot on. :-) SAI is a subset of self-tests of intelligence, that can range from simple estimates, to full-fledged self-administered IQ tests. As such, correlations can vary a lot. However, SAI is generally considered to be an estimate, rather than a test, and this does not appear to be affected much by methodology. From Paulhus et al (1998):

> Correlations between single-item self-reports of intelligence and IQ scores are rather low (.20–.25) in college samples. The literature suggested that self-reports could be improved by three strategies: (1) aggregation, (2)item weighting, and (3) use of indirect, rather than direct, questions. ... Although results showed some success for both direct and indirect measures, the failure of their validities to exceed .30 impugns their utility as IQ proxies in competitive college samples.

On the other hand, the SAI literature reveals significant gender differences in SAI estimates - with males significantly overestimating and females significantly underestimating their intelligence - as well as significant cross-cultural differences in estimates, suggesting that the correlation is more heavily affected by social stereotypes.

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Tags: intelligence, bias
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# Question
Title: Are there emotions that motivate pattern completion?
I have been studying musical "tension." Musical tension essentially refers to the "expectations" one builds up in a melody that are then "released" when a stimulus matching the expectation occurs. For example, if you play the white notes on a piano in order CDEFGAB, you have a "tension" that motivates you to finish the scale and play C to complete the pattern.

I am aware pattern completion occurs in the brain and have seen a few biological models of this. For example, with attractor network models of human memory. So I am not surprised obviously that pattern completion occurs. But this example with musical tension highlights how there is an *emotion (aka drive or motivation)* that compels me to complete the pattern. When I hear the sequence CDEFGAB, I am *compelled* to finish the sequence.

**My Question**

Can someone provide me of examples of canonical models of emotions influence on pattern completion? I would like to learn example mechanisms as to how, on a circuit level, emotion would influence pattern completion. I am particularly interested in examples relating to common forms of human creativity like visual art, problem-solving, etc., but any examples will do.

# Answer
Canonical models of emotions in relation to pattern comclusion can not be provided.

The emotional of the musical sequences completion are directly related to the tonality.

Emotions related to the tonality are presented in the semantic memory.

It is possible the study of a partial mapping that relates tonality and emotions.

The best text, in my opinion, is: Sloboda, John, A. (1985). The Musical Mind: The Cognitive Psychology of Music. This is a compilation of numerous research in this area, others very interesting books can be found of this author.
> 1 votes

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Tags: cognitive-psychology, music
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# Question
Title: What are some theories or cognitive models of human imagination?
What cognitive models of human imagination exist? How does the human imagine things that don't exist?

Suppose I ask anyone to imagine himself climbing a mountain. He can't imagine that until he has some experience about mountaineering whether through a movie, documentary or some reading material and Wikipedia page on Imagination says that

> ...without knowledge, imagination can not be developed...

If he has this experience he would be able to imagine himself climbing a mountain. Are there any theories that explain this?

# Answer
> 1 votes
Assuming imagination can be roughly defined as "taking things from reality/experience and mixing them up somehow to create something dissimilar from the inputs", then any cognitive framework:

* with a probabilistic interpretation
* who is capable of analogy

roughly models how imagination may manifest itself in the human mind.

# Imagination as inference

Imagine you've ridden two bicycles: a fast bicycle and a slow bicycle. The bicycle salesman now shows you a third bicycle with a speed in between the two you've previously ridden. Although you do not have any direct experience with the bicycle, you can infer from your two previous experiences that the bicycle will give you an experience somewhere in between the two. This is what I mean by "probabilistic interpretation". If your cognitive model has a concept of a distribution of possible bicycle speeds, it can *infer* points along that distribution. This approach is used in cognitive models like neural networks.

# Imagination as analogy

Consider the analogy:

> Structure of an atom is like a solar system. Nucleus is the sun and electrons are the planets revolving around their sun.

Given basic knowledge of the solar system, despite never seeing atoms, you can imagine a few things about atom structure. You can imagine electrons float freely around the center of the nucleus without slowing down. You were able to combine a symbol you had for the solar system with the unknown symbols of electrons and nuclei. This type of imagination is found in cognitive models like ACT-R.

# Imagination as something more complicated

The two previous forms of imagination were pretty simple in terms of interactions. Two inputs formed a novel output, but scientists have all sort of theories about how we build models in our heads that involve scaling up to more than one input, drawing experiences from memory and interacting with the environment. There are so many that you have to start developing criteria for what the best model of imagination is. Obviously, I can't cover all the models, but hopefully this gives you a good starting point.

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Tags: cognitive-psychology, cognitive-neuroscience, cognitive-modeling, creativity
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title: Psychology literature on present bias

text:
# Question
Title: Psychology literature on present bias
Does anyone know some good psychology papers on present bias that discusses the psychological mechanisms underlying this bias?

I can only seem to find papers by economist and they tend to give a quite formal and mathematical explanation of the subject. I'm looking for an in depth explanation of the psychology behind present bias.

# Answer
> 1 votes
I think the present bias is a result of the immediate gratification tendency that we as humans have. The following extracts are from the book Smart Change: Break the habits that hold you back and form the habits of success by Art Markman

> One of the most difficult things for people (and other animals for that matter) is to pass up something desirable right now in favor of something else in the future. A piece of cake now has a stronger pull on our actions than having a beach-ready body by next summer. An afternoon playing video games feels like a better way to spend an afternoon than studying for an exam that won’t happen for another week. Checking a few emails at work feels more productive than putting in effort on a big long-term project that won’t be finished for months. You’re wired to want to do what feels good in the short term.
>
> A beautiful experimental method for looking at the difficulty of overcoming temptations was developed by Walter Mischel in the late 1950s to study how children deal with temptation. In his studies, an experimenter asked four-year-old children to sit in a room and showed them a small tempting object like a marshmallow or a cookie. Then the experimenter placed the object in front of the child next to a bell and said that he had to leave the room for a while. If the child was able to wait until the experimenter got back, then the child would get a larger reward (like two marshmallows or cookies). However, the child could ring the bell at any time and just take what was on the plate. If the child was able to wait fifteen minutes, then the experimenter would come back in the room and give the child the bigger reward.
>
> In a typical experiment, the average child was able to go only about ten minutes before ringing the bell. Factored into that average are the many children who rang the bell soon after the experimenter left the room and others who were able to wait the full fifteen minutes. Even for those children who are successful at waiting, it can be a difficult experience. In fact, there are a number of popular videos on YouTube of children in these experiments agonizing over the marshmallows in front of them. It is funny to see the children struggle to wait for the bigger reward. But the videos also illustrate how hard it can be to overcome temptation.

In the above experiment although the future benefits are clearly better (two instead of one marshmallow), the now is weighted more.

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Tags: cognitive
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# Question
Title: Is k-winner a biological plausible model of inhibition?
In the Leabra cognitive architecture, sparse representations are created by simply ignoring all but the k strongest activations, if I understand correctly. In Hierarchical Temporal Memory, instead, each firing neuron inhibits an area of a given radius during this time step. To me, this seems more plausible due to the locality of neuronal connections.

Is the k-winner inhibition biologically plausible?

# Answer
> 3 votes
As mentioned by honi, it is possible to have bio plausible k-means. However, neither Leabra nor Hierarchical Temporal Memory (HTM) use it.

As Section 3.5.1 of How to Build a Brain by Chris Eliasmith notes:

> There are basic computational methods underlying Leabra that are of dubious plausibility. The most evident is that Leabra directly applies a k-Winner-Takes-All (kWTA) algorithm, which is acknowledged as biologically implausible: “although the kWTA function is somewhat biologically implausible in its implementation (e.g., requiring global information about activation states and using sorting mechanisms), it provides a computationally effective approximation to biologically plausible inhibitory dynamics” (http://grey.colorado.edu/emergent/index.php/Leabra; see also O’Reilly & Munakata \[2000\], pp. 94-105 for further discussion). In other words, the actual dynamics of the system are replaced by an approximation that is computationally cheaper on digital computers.

The same problem occurs with the HTM as discussed in this forum post by Travis DeWolf:

> In the second step of their spatial pooling, they find the k most active columns, to apply learning to only these columns. Dynamically, setting up WTA with lateral inhibitory connections is notoriously very tricky, and isn't something that can be done in a single time step. On top of that, controlling the learning so that it's only applied after the network has settled on a set of winners is a whole other issue. It might be the case it works running the whole time as the WTA circuit settles, but the dynamics are complex and can't just be assumed to work.

To summarize, k-winner inhibition is possible, but it's not used in a biologically plausible manner in either Leabra and HTM.

# Answer
> 2 votes
Yes, see "A Second Function of Gamma Frequency Oscillations: An E%-Max Winner-Take-All Mechanism Selects Which Cells Fire" by de Almeida, et al., 2009 for a biologically plausible implementation.

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Tags: neuroscience, cognitive-modeling
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title: Why do colors affect emotion?

text:
# Question
Title: Why do colors affect emotion?
The paper "Color Psychology: Effects of Perceiving Color on Psychological Functioning in Humans" by Andrew J. Elliot and Markus A. Maier shows color effects emotion, but what property of them cause this effect? Does light blue make you feel peaceful because it is the color of the sky, or because the wavelength causes something in the brain to feel peaceful? Basically, are the color emotions controlled by association or something else?

# Answer
> 6 votes
Our emotional responses to colors is based on two factors : innate behavior and acquired behavior (aslo known as nature and nurture).

**Innate behavior** is build in our genes, it is instinctive and performed without being based upon prior experience (that is, in the absence of learning), and is therefore an expression of innate biological factors. This innate behavior is formed through evolution. The evolutionary aesthetics can explain the innate factor of emotional response to colors.

> Evolutionary aesthetics refers to evolutionary psychology theories in which the basic aesthetic preferences of Homo sapiens are argued to have evolved in order to enhance survival and reproductive success.
>
> Based on this theory, things like color preference, preferred mate body ratios, shapes, emotional ties with objects, and many other aspects of the aesthetic experience can be explained with reference to human evolution.

**Acquired behavior** is formed through our exepriences with the world. Our day to day interactions with our enviroment creates emotional responses and some of these responses are associated to certain colors. Also the culture has a great influence on how we interpret and subsequently emotionaly response to colors.

examples of cultural color associations:

* > Take France, for example, where yellow signifies jealously, betrayal, weakness, and contradiction. In the 10th century, the French painted the doors of traitors and criminals yellow.
* > In Japanese culture, yellow has represented bravery, wealth, and refinement since the War of Dynasties in 1357. During this time, warriors wore yellow chrysanthemums—which represent the emperor in Japan and royal family—as a pledge of courage.

some addtional articles:

https://en.m.wikipedia.org/wiki/Color\_psychology

https://www.psychologytoday.com/blog/the-new-brain/201104/why-we-prefer-certain-colors

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Tags: cognitive-psychology, color
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# Question
Title: Biological Plausibility of FORCE training
In "Supervised Learning in Spiking Neural Networks with FORCE Training" by Wilten Nicola and Claudia Clopath. The authors create a learning rule for learning non-linear dynamics from populations of spiking neurons. The learning rule only seems to depend on:

1. an error signal
2. the firing rates of each neurons
3. an approximate inverse correlation matrix calculated from the firing rates of each neuron

Is it possible to calculate the inverse correlation matrix of using another population of neurons or is there some biological mechanism that could be used to explain this? Additionally, is this calculation sensitive to delay? Often, forgetting to take delay into account is the undoing of many learning rules and cognitive architectures.

# Answer
> 2 votes
From the paper:

> Although FORCE trained networks have dynamics that are starting to resemble those of populations of neurons, at present all top-down procedures used to construct any functional spiking neural network need further work to become biologically plausible learning rules \[Sussillo and Abbott, 2009, Boerlin et al., 2013, Eliasmith et al., 2012\]. For example, FORCE trained networks require non-local information in the form of the correlation matrix $P(t)$. However, we should not dismiss the final weight matrices generated by these techniques as biologically implausible simply because the techniques are themselves biologically implausible. More work should be done in implementing either FORCE, NEF, or spike-based coding networks using a biologically plausible learning mechanism based on synaptic plasticity or homeostasis \[Bi and Poo, 1998, Pfister and Gerstner, 2006, Clopath et al., 2010, Graupner and Brunel, 2012, Babadi and Abbott, 2016, Vogels et al., 2011\]. This has been resolved for spike-based coding networks and linear dynamical systems for example \[Bourdoukan and Deneve, 2015\]

Basically, calculating the correlation matrix $P(t)$ requires every neuron to know what every other neuron is doing, so the FORCE algorithm isn't biologically plausible. I'm not sure what alternative there would be calculating the correlation matrix. Maybe there's some mathematical way to approximate it gradually over time?

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Tags: neuroscience, theoretical-neuroscience
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# Question
Title: How to track eye movements with electrodes?
I'm an Information Technology student (bachelor's degree) and as a summer project, I'd like to develop a small "alarm" system for ALS patients in case of emergency situations.

I thought about tracking the eye movements of the patients via electrodes and then send the eye movement signals to the software system which I'm going to develop and then process the data. I'm planning to use Python programming language since I already have some experience on.

However, I don't have any experience with using electrodes, processing the signals to detect eye movements. Do you know any good and simple online sources for the beginners like me? I can't afford to buy books so I'd be grateful if you can suggest me free online sources.

# Answer
> 4 votes
I believe this tutorial covers exactly what you are looking for. It describes how to use a relatively cheap kit ($150) to detect eye movements and eye blinks. It includes software and hardware information.

# Answer
> 2 votes
Detecting eye movements is generally referred to as **oculometry**.

Oculometry can be performed using your suggested approach, namely with electrophysiological techniques. In this case the recordings are based on the dipole character of the eye. This characteristic results in detectable voltage differences when the eye moves with respect to a stationary electrode pair.

Oculometry can also be performed using an eye tracker (*e.g.*, Liston & Stone, 2014)). This technique is based on recording the position of the pupil using infrared cameras.

A recent fairly detailed, yet accessible paper on electrophysiological oculometry can be found in Liston *et al*, (2016).

Eye trackers can be an interesting alternative for you. They come in a vast range of prices. Due to the advent of eye trackers used in gaming, there are highly affordable eye trackers on the market nowadays (*e.g.*, from Tobii for a little over $100). The one I am using for scientific purposes in a clinical setting from SMI. it is CE marked and deemed safe. However, it comes with a price tag of over 15k. The SMI system, alongside the Arrington devices are used worldwide in clinical settings.

<sub>**References**
**-** Liston *et al*, *Optomy Vis Sci* (2017); **94**(1): 51–9
**-** Liston & Stone, JOV (2014); **14**(14): 1-17</sub>

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Tags: reference-request, methodology, eye-movement, brain-computer-interface
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title: Why is PES biologically plausible?

text:
# Question
Title: Why is PES biologically plausible?
The NEF puts great emphasis on biological plausibility. However, I'm not clear on why the Prescribed Error Sensitivity (PES) learning rule, used in many NEF-based models, is considered to be biologically plausible. I've heard that:

* It doesn't rely on any globally shared information between neurons
* It empirically replicated various aspects of STDP

But I'm not sure how it does these things or why that's important. Specifically, what would an alternative to PES have to demonstrate to show they had improved biological plausibility?

# Answer
> 2 votes
For a learning rule to be biologically plausible, it has to only depend on knowledge/information local to the neuron (no global information about the neuron population) and has to match experimental neuroscience data.

# Only Neuron-Local Information

As discussed in "Simultaneous unsupervised and supervised learning of cognitive functions in biologically plausible spiking neural networks" by Bekolay et al., the effect of the PES learning rule on the decoders $\Delta \mathbf{d}\_i$ is formulated as:

$$\Delta \mathbf{d}\_i=\kappa \mathbf{E}a\_i$$

* $\mathbf{E}$ is the error vector is mapped onto individual neurons which also represent vectors of the same dimension. Biologically, the error vector is theorized to be dopamine levels.
* $a\_i$ is each neuron activity level, which in the NEF is defined as a combination of the neuron's encoder and it's activation function. See Principle 1 of the NEF for more detail.
* $\mathbf{\kappa}$ is the error scaling factor

All of these variables only require information local to the neuron. From the paper:

> The key difference between this rule and backpropagation is that the global-to- local mapping is done by imposing the portion of the error vector space each neuron is sensitive to via its encoder. This limits flexibility, but removes the dependency on global information, making the rule biologically plausible.

# Matching Neuroscience Experiments

To actually match experimental STDP spiking data, PES must be combined with the Bienenstock, Cooper, Munro (BCM) learning rule to enforce sparsity on the encoders. This creates the homeostatic PES rule (hPES).

This matches the following experiments from "Synaptic modification by correlated activity: Hebb’s postulate revisited" by Bi and Poo.

# Other Replications

In addition to these experiments, there are various papers that use the PES learning rule to replicate things such as a model of Fear Conditioning and a model N-Armed Bandit Task, however this evidence isn't necessarily unique to the PES learning rule.

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Tags: neuroscience, theoretical-neuroscience, cognitive-modeling, nef
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# Question
Title: Why do we need to break down long sentences to understand them?
Why do we need to break down long sentences that won't immediately scan? Is it an attention thing? Working memory, executive function?

For example:

> Studies show that if there are many stimuli present (especially if they are task-related)...".

is a straightforward sentence. The only ambiguous term is "they". Does it mean "studies" or "stimuli"? In this case it is, obviously, stimuli, but the issue seems to be that i need to read the "they" slower, and am not primed to. What part of cognition is being tested?

# Answer
> 1 votes
First off, the difficulty in the specific example given in the question is more a matter of **proper writing** habits than anything else. The use of **parentheses** is often discouraged because it **disrupts sentence structure** and therefore **interferes with the flow of information**. Secondly, the use of referring words (pronouns) to earlier parts of the sentence are generally encouraged, barred that the pronoun is unambiguous. In the example the pronoun is ambiguous, as both '*stimuli*' and '*studies*' can be '*task-related*'. The cited sentence is therefore a prime example of how *not* to write a decent English sentence and could be a textbook example for Scientific-English writing courses.

In terms of cognition, it is indeed related to working memory, as you need to remember the words in the earlier part of the sentence. Of course attention (vigilance) is needed to extract the information in the sentence. Executive function therefore is involved, as it includes all aforementioned processes.

# Answer
> 0 votes
To understand why long sentences are difficult to parse we need to understand how we generally parse sentences. In linguistics, often, parse tree are used to show how people structure sentences:

**Parse Trees**

A parse tree is a tree structure in which sentences (S) are deconstructed in different phrases. There are

* noun phrases (NP), in which a noun (N) accompanied by a determinant (D) are stored.
* verb phrases (VP), in which a verb (V) and an object are stored.

The object can be many many things. As you can see in the below picture, another NP is added, to finish this simple sentence.

In this incredibly simple example, it is clear that we do not need to break down the sentence that much, nor is there any ambiguity. However, sentences can become more complex, by adding a prepositional phrase (PP):

**Complexity and ambiguity**
The longer sentences are, the more complex these trees become. **The difficulty** in creating these trees **is finding the correct relations between phrases** and, therefore, the structure of the tree. In some cases, even multiple sentences must be combined in one tree:

The second sentence is what comes below SBAR, the auxiliary node for a new S. Moreover, as you can see, there is a line leaving the right side of the picture. The sentence could thus become even longer and more complex.

When sentences are ambiguous, it is even possible to construct multiple trees that are correct, but have a different meaning. There are ways to notate these ambiguous trees, but I won't/cannot go into that. At linguistics.se, there is a question covering that.

Also, here is a post about creating parse trees/syntax trees in general, including a reference.

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Tags: linguistics, reading
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# Question
Title: What projective tests are available for a child and family assessment?
I’m thinking about introducing to my practice some new tests for family relationship evaluation. There are not so many projective tests in this matter. I'm particularly interested in Family Relation Test: Children’s Version (FRTC), however, I couldn’t found any information about a real experience of this test usage by specialists, only its general description on the website of a publisher. What are the strengths and the weaknesses of FRTC?

In general, what projective tests for a child and family assessment are there on the market today, except of classic drawing tests or TAT?

# Answer
Many projective tests explore family relationships, however it is frankly difficult to find projective tests exclusively focused on family relationships, can be proved:

* The Family Drawing Test (the most utilized).
* CAT (version of TAT for children) very, but very used.
* Test by Patte Noire of Louis Corman.
* FTT Riding theory test of Carina Coulacoglou.
* Test of Luisa Düss.
* TRO of Phillipson (officially focused on a person's ability to establish satisfying relationships with others, emotions in relationships)
> 3 votes

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Tags: measurement, personality, test
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# Question
Title: Is cortical magnification in the visual system related to synaptic pruning, or is it a separate developmental or learning process?
I'm primarily interested in learning about current computational models that explain cortical magnification in the visual system.

With this in mind, my specific questions are: (1) Is this phenomenon a result of the synaptic pruning that takes place in the early years of development? (2) If not, is it a separate "learning" process along the lines of the hippocampus enlargement in London cab drivers?

I would personally like it if the answers were (1) NO (2) YES, but I'd like to know what the latest science says.

# Answer
> 2 votes
No, it's not due to synaptic pruning. If it were due to synaptic pruning babies would have better vision(esp. Peripheral) but that is not the case. Babies only have better hearing.

No, it is not exactly a learning process. Most of the foveal developmental starts during the prenatal period and complete by 18 months postnatal.Most of the inter-individual variance have been linked to genetic factors. There is no conclusive evidence for environmental factors affecting the foveal development. But there is speculation for possible environmental factors.

Reference : https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3658155/

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Tags: vision, theoretical-neuroscience, computational-modeling, brain-development, perceptual-learning
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title: Yerkes-Dodson Law and Drugs

text:
# Question
Title: Yerkes-Dodson Law and Drugs
According to the Yerkes-Dodson Law, there is optimal point of arousal and performance. Suppose a person takes a stimulant such as Adderall. This would increase his arousal. However, it may increase his anxiety (e.g. side effects). Would combining a "downer" (such as alcohol) with an "upper" (such as Adderall) maximize productivity? This is assuming that at a baseline level, a person cannot maximize his productivity.

# Answer
I think in this case, you should look at 2 graphs of optimal performance. So one inverted bell curve (Yerkes-Dodson Law)for the stimulant, and another for the 'downer'. So in this case, each has their own optimal productivity, and an interaction of the 2 isn't just a simple combination, because this would be a third graph altogether. So unless there is something you know of the exact interation effect of the particular stimulant, and particular depressant,I wouldn't risk mixing them for optimal productivity.
> 1 votes

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Tags: performance, drugs
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# Question
Title: Does risk of developing depression continue to increase after age 60?
Age is a risk factor for depression when we look at the entire lifespan. Does that hold true in a population of \>60 years old?

# Answer
> 2 votes
In addition to the articles that @Seanny provided in the comments, I think this study addresses your question pretty well. A couple of idiosyncrasies about the sample: from rural Germany, primary care attenders, 75 and over (Weyerer et al., 2008).

Results are somewhat mixed: univariate analysis shows a positive relationship between age and depression (accounting for sex), while adjusting for all possible confounding variables make the effect not statistically significant (though still positive).

What does this mean? Yes, there is a positive relationship between age and depression. However, the relationship may not be distinct from other aspects of old age (mobility impairment, visual impairment, etc.) that increase in prevalence as age increases.

**References**

Weyerer, S., Eifflaender-Gorfer, S., Köhler, L., Jessen, F., Maier, W., Fuchs, A., … Bickel, H. (2008). Prevalence and risk factors for depression in non-demented primary care attenders aged 75 years and older. Journal of Affective Disorders, 111(2–3), 153–163. http://doi.org/10.1016/j.jad.2008.02.008

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Tags: clinical-psychology, depression
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# Question
Title: Comparison of Aversion Therapy to other interventions for nail-biting
A product Pavlock, which is essentially a shock bracelet for Aversion Therapy, markets itself as an intervention for a range of habits, including procrastination and nail-biting. Wikipedia cites the paper "A Pocket-Portable Shock Device With Application To Nailbiting" from 1968. Are there more modern comparison of Aversion Therapy to other interventions? Particularly to nail-biting, since there are many applications of Aversion Therapy across addictions.

# Answer
One of the techniques used for nail-biting is the (training) **habit-reversal**: Developed by Nathan H. Azrin and R. Gregory Nunn (1987) focused on the treatment of nervous habits (although in general, other authors in the clinical field developed it under different variation). It is not usually as well known as it should be, since during that time many techniques conditions were experienced: reciprocal inhibition and counterconditioning (Joseph Wolpe), exposure, alternative response, incompatible response.

Key:

* Given a habit that we could qualify as negative linked to nerves or anxiety, select a response that ideally is incompatible with the negative habit (in any case compete strongly). **The incompatible response fulfills the objectives, goals, motivation or causes** that satisfied the negative habit, precisely about nervous habits is not convenient an increase of the anxiety, the person has developed the negative habit for reasonable reasons, whatever they are, and that habit is somehow adaptive and positive, surely to reduce anxiety). As in the case of self-instruction, it is not the point of whether the psychologist or therapist, or the client, select one or the other response, but must be meaningful and optimal for both of them.

Therefore it would be advisable to master previously:

* Background, causes and triggers of behavior (**motive or motivation of activity**).
* Knowledge about anxiety (**different anxiety profiles**) and exposure.
* Reciprocal inhibition and counterconditioning.
* Therapy based on the alternative response.
* Therapy based on incompatible response.

A very flexible and wide-ranging approach so that it can be integrated as a training and in conjunction with other techniques.
> 2 votes

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Tags: reference-request, behaviorism, addiction
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# Question
Title: Determining if participants learned the objects as a whole or feature by feature
I want to know if in an experiment participants will learn the object as a whole or feature by feature.

Let's say, my objects are geometric shapes, and its features are color and orientation.

Would it be a good idea if I do something like:

> 1. Assign each object a unique color and a unique shape
> 2. Randomly assign participants to either color or orientation group
> 3. Tell participants to pay attention to "the" feature of objects (color or orientation, according to the group they belong) (this "paying attention" can be done in several ways, for example by asking participants to do an $n-$back task only with "the" feature)
> 4. Show objects to the participants on a screen in random order, possibly many times.
> 5. Suprise recognition task. Sometimes they will see exactly the same object, sometimes the orientation will be the same, but color will be different. Sometimes both color and orientation will be different *etc.*

My questions are:

Does this experiment measure what I want to measure?

Can you suggest some keywords for the above situation? Binding problem is somehow related but it is not exactly what I am seeking for.

# Answer
Your experiment is most similar to those in categorization research. For example, Wills et al (2013)\* argued that **single-dimension** classification (one-feature analysis) is less effortful, than multidimensional with more than one dimension, and **omni-dimensional**, where you process and categorize the stimuli as a whole. They used the **match-to-standard** procedure, where each stimuli is classified by participants as members of categories. This task was first used by Regehr and Brooks (1995) and basically means that you map each the stimuli features and each stimuli feature that you categorize.

For example, you have Stimulus A (dark, square), Stimulus B (light, triangle) and Stimulus C (dark, triangle). The dimensions are shape and colour.

`Dimensions colour shape
Stimulus A 1 0
Stimulus B 0 1
Stimulus C 1 1`

Of course you have to have to set up rules for stimuli structures in category learning or learning in general and fit the stimuli into those structures.

If you instruct them to pay attention to the first dimension only, you would pay attention only to the first dimension in the data analysis. But that would be supervised learning, and that would defeat the purpose of your experiment. If you are curious to whether they learn by single-dimensions or through omni-dimension, you must not supervise the learningand should not provide feedback, because feedback will likely become superior to simple observational learning (see Wills, Milton & Edmunds, 2015).

A very good example is Nosofsky et al. (1994) replicating Shepard et al. (1961). That one is the closest to what you described you want to do. You can find the data and look at the categorisational structure in catlearn (Wills et al., 2016), so you can see how they handled their stimuli dimensions and data.

*Hope this helps. I might have not been too coherent, but I think the gist is there.*

Nosofsky, R. M., Gluck, M. A., Palmeri, T. J., McKinley, S. C., & Glauthier, P. (1994). Comparing modes of rule-based classification learning: A replication and extension of Shepard, Hovland, and Jenkins (1961). Memory & Cognition, 22(3), 352–369.

Regehr, G., & Brooks, L. R. (1995). Category organization in free classification: The organizing effect of an array of stimuli. Journal of Experimental Psychology: Learning, Memory, and Cognition, 21(2), 347–363.

Shepard, R. N., Hovland, C. I., & Jenkins, H. M. (1961). Learning and memorization of classifications. Psychological Monographs: General and Applied, 75(13), 1.

Wills, A. J., Connell, G. O., Edmunds, C. E. R., & Inkster, A. B. (2016). Progress in modeling through distributed collaboration: Concepts, tools, and category-learning examples. Psychology of Learning and Motivation, 1–23.

Wills, A. J., Milton, F., & Edmunds, C. E. R. (2015). Feedback can be superior to observational training for both rule-based and information-integration category structures. Retrieved from https://pearl.plymouth.ac.uk/handle/10026.1/3064

Wills, A.J., Milton, F., Longmore, C.A., Hester, S., & Robinson, J. (2013). Is overall similarity classification less effortful than single-dimension classification?. Quarterly Journal of Experimental Psychology, 66, 299-318.

* You can visit the authors' website to get the data and how the analysed that data.
> 4 votes

# Answer
In your experiment you are directing participants attention to a sepcific feature, in order to accomplish a difficult task. This experiemnt in my humble opinion does not test your hypothesis, probably it will replicate the findings of the invisible gorilla experiment. Particiapnts will not pay attention to any other irrelevant features.

An experiment that I find related to your hypothesis is the Schyns and Rodet's (1997) feature creation experiment. The extracts below are from this article

> Design of Schyns and Rodet’s (1997) feature creation experiment. From left to right, the top pictures are Martian cell exemplars from the XY, X, and Y categories. From left to right, the bottom pictures are the features xy, x, and y, defining the categories. Note that the feature xy is a combination of feature x and feature y. Subjects in the XY--\>X--\>Y (vs. X--\>Y--\>Y) group learned the category in this order.
>
> The reasoning was that subjects should categorize X-Y cells as XY members if they perceived and represented XY as a conjunction of two individuated features. Results revealed that only one group (X--\>Y--\>XY) performed this categorization; the perception of XY in the other group prompted X or Y classifications of X-Y. In sum, orthogonal classifications of X-Y, when its component features were both clearly perceived and used in the experimental groups, suggested that different features were acquired to analyze perceptually and to represent XY. Network simulations further suggested that the feature vocabularies were X--\>Y--\>XY = \[x,y\] and XY--\>X--\>Y = \[xy,x,y\], respectively.
> 2 votes

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Tags: cognitive-psychology, perception, recognition
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# Question
Title: How does the L-game by Edward de Bono demonstrate lateral thinking?
From the information I gathered about lateral thinking, it means to solve problems using unconventional means, sometimes even without using logic. Edward de Bono invented the L-game to illustrate lateral thinking. However, I fail to see how lateral thinking is used in solving the game. The L-game is essentially a very simplified version of Chess, both are strategy games and Chess is almost always the textbook example of logical games. In the analysis of the L-game, I found myself using purely logic (i.e. working backwards from the losing positions and identify which positions are "dangerous" etc). I do not see how "illogical means" could better help a player in winning the game. I might have misunderstood the meaning of lateral thinking, could anyone clarify?

# Answer
The idea is not to **use** lateral thinking to win the game, but to **teach** people to think laterally.

The **L** can be flipped and/or rotated as well as translated - why should you do a particular transform, and when. What move to make requires a certain amount of lateral thought.

Similarly in moving a neutral piece - not all the moves available are immediately obvious to a novice player - they must learn them.

By the time someone has mastered a few of the advanced moves, they are beginning to think laterally (at least that is the idea!).
> 2 votes

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Tags: cognitive-psychology, creativity
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# Question
Title: Are all dendrites targeted by an axon, or are there a lot of "empty" dendrites?
As far as I understand, one neuron can have up to 200 000 dendrites (e.g. purkinje cells). As for axons, there can be only one per neuron, which can divide into thousands (but not hundreds of thousands) of branches at the end.

I assume that each dendrite has one input terminal and each axon branch has one output terminal. I also assume that only dendrites can have input terminals and that only axons' branches can have output terminals. So we can have up to 200 000 input terminals and up to thousands of output terminals per one neuron. So it seems to me like in the whole brain we have **more input terminals than output terminals** available.

Are my assumptions correct?

If yes, does that mean that there are a lot of **redundant dendritic input terminals** available?

# Answer
**Short answer**
Axonal outputs are coupled to dendrites or other effector tissues, such as muscular fibers or glandular tissue. There are no redundant axonal outputs, or redundant dendritic inputs. There is a tight coupling between the two both during developmental formation of synapses and during the maintenance of the two.

**Background**
Neurons can have extensive dendritic trees (*e.g.*, Purkinje cells in the cerebellar cortex, Fig. 1) and also elaborate arborated axon terminals (\*e.g., in the neuromuscular junction, Fig. 2).

In the cases shown below, the functions can be defined as simple logical operators, namely integration (Purkinje cell) and amplification (neuromuscular junction). The Purkinje cells receive and integrate input from the brainstem. The motoneurons innervating muscle use multiple axon terminals to target a larger area of the muscle so that stronger, synchronous muscle contractions can be achieved.

The development and maintenance of dendrite-axon connections are tightly coupled (*e.g.*, Shen & Lowan, 2010). Generally, when either input to the dendrite is diminished (axonal regression), or output of the axon is cancelled (dendritic regression), the plasticity of the neural tissue will lead to degeneration or re-directing of the axon, or regression or re-innervation of the dendrite, respectively (*e.g.* Marc *et al*., 2003).

As regarding to your math; be aware axons *can* branch, axon arborations can target a single dendritic tree, axons can terminate on other tissues, such as glands and muscles (no dendrites there!). In other words, your mathematical example is an oversimplification. Further; cells with elaborate dendritic trees as shown in Fig. 1 are common in cortical layers, but are not the norm. The ratios of the cell types have to be taken into account as well.

Lastly, there can be the textbook connections between neurons, namely **axo-dendritic** connections, but also **axo-axonal** (Schmitz *et al*, 2001), **dendrodendritic** (Shepherd, 2009), and even **axosomatic** synapses between neurons (Fig. 3).

Fig. 1. Dendritic tree (Wundt, 1904)

Fig. 2. Axonal terminals in a neuromuscular junction. source: Farrel (2017)

Fig. 3. Different kinds of synapses. source: Modesto Junior College

**References**
**-** Marc *et al*., *Prog Retin Eye Res* (2003); **22**(5):607-55
**-** Shen & Kowan, *Cold Spring Harb Perspect Biol* (2010); **2**(4): a001842
**-** Shepherd, *Ann N Y Acad Sci* (2009); **1170**; 1-11
**-** Schmitz *et al*., Neuron (2001); **31**(5): 831-40
**-** Wundt, Principles of Physiological Psychology (1904)
> 3 votes

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Tags: neuroscience, neurophysiology, neuroanatomy
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# Question
Title: What effect do random visitors have on children in orphanages and people in old age homes?
Leading a volunteering team, I've been to an orphanage where the sister (who did a psychology course) running the orphanage was strict that volunteers should spend a minimum of 3 months teaching the kids on the weekends if they wanted to, because kids develop an attachment to the visitors. Another NGO insists that volunteers pledge a minimum of one year if they wish to mentor a child.

At another orphanage which is frequented by volunteers of many companies, a worker there said that the kids were accustomed to seeing strangers everyday. Girls at an orphanage in Delhi told my friend (head of an orphanage in Bangalore) that they don't like it when (well-meaning) visitors arrive and ask them to stand in front of them and narrate a poem or sing a song for them.

As a volunteering leader, I encourage people to contribute to society meaningfully. I want to know what the best psychological/emotional effect we can have on the children. Would it be bad for the children in the long-run, to see strangers come to conduct events for them where they sing and dance, distribute snacks and gifts and then the kids never get to see these people again. People from various companies visit these kids. Is it better to not conduct such events, and instead ensure that volunteers visit these kids weekly/monthly, find out what their needs are, become familiar with the kids and help them in whatever way possible?

The problem here, is that a lot of volunteers see what other companies are doing, and are more interested in conducting a grand event at orphanages/old-age-homes, donate money or gifts and then walk away. They say they don't have the time for multiple visits.

1. Should I discourage people to do this? (a friend described it as being similar to visiting a zoo)
2. Shouldn't they spend more time with the children/senior-citizens? Empathy and understanding.
3. Won't it just reinforce the kids/senior-citizen's belief that nobody really cares about them?
4. Is there any research done on the psychological/emotional effect this has?

# Answer
> 15 votes
There is indeed research done on the topic. Some links:
http://www.thinkchildsafe.org/thinkbeforevisiting/
http://www.hsrc.ac.za/HSRC\_Review\_Article-195.phtml
http://www.thinkchildsafe.org/thinkbeforevisiting/resources/Misguided\_Kindness.pdf
http://www.thinkchildsafe.org/thinkbeforevisiting/resources/UN%20Guidelines%20Alternative%20Care.pdf
http://en.wikipedia.org/wiki/Volunteer\_travel

**Extracts:**

> A child's right to privacy Under international law, children in orphanages have the same rights as children across the globe to have a safe and private home setting. Short-term orphanage visits from tourists and travelers lowers a child's privacy inside their own home. Additionally, reports show that short-term visits can cause harm to a child's development and emotional wellbeing. We think everyone agrees that children need safety, privacy and stability.

and

> **How do I harm children by visiting an orphanage?**
> Many orphanages rely almost entirely on donations from visitors to survive. Thus directors may purposefully maintain poor living conditions for children to secure funds from tourists. Children who appear underserved may come across as a cry for help more than children who appear well fed and cared for. This of course places guilt on tourists if they do not help immediately. By visiting orphanages and making a donation you may be fuelling a system that exploits children.

and

> Institutionalised children will thus tend to manifest the same indiscriminate affection towards volunteers. After a few days or weeks, this attachment is broken when the volunteer leaves and a new attachment forms when the next volunteer arrives. Although there is little empirical evidence on children's reactions to very short-term, repeat attachments over time, evidence from the study of children in temporary or unstable foster care indicates that repeated disruptions in attachment are extremely disturbing for children, especially very young children.

# Answer
> 3 votes
Nav has already provided a fantastic answer, but I wanted to add a short bit more (primarily to highlight this fantastic post on the subject, not by me) addressing some of the questions in your post (not the title question).

First off, I see this problem as one that is very similar to problems with generic short term missions trips. The above post describes some key facets of the problem. The main one is that when many people engage in a short term missions trip, *they* tend to walk away with the expectation of an experience (the experience of "helping"). This is highlighted through "the desire to do a grand event... and then walk away." Orphans and the elderly are complex populations and vulnerable in almost every sense of the word. They deserve a more careful consideration.

How is this then addressed? A major component to a holistic solution is the community engagement movement. Many aspects of this are listed in your question "...find out what their needs are, become familiar with the kids and help them in whatever way possible" *that they need*! The idea is to focus on real needs of the community, and not things that make the volunteers feel good. There is even a nice guide on community engagement found here and formally referenced below.

All of the above being said, I'll add a caveat: sometimes funders will be less inclined to donate if it doesn't *feel* like they "did something." So, while there may be better ways for orphans and elderly to be helped (than "narrate a poem"), there may be an offsetting cost of less funding and time donated to the cause. As you have noted, less people are interested in the longer haul.

**References**

Ahmed, S. M., & Palermo, A.-G. S. (2010). Community Engagement in Research: Frameworks for Education and Peer Review. American Journal of Public Health, 100(8), 1380–1387. http://doi.org/10.2105/AJPH.2009.178137

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Tags: emotion, developmental-psychology
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# Question
Title: What happens in my retina if I press on my eyeballs?
If I press my eyes I can "see" all kind of things: sparkling blue dots (which sometimes seem random and sometimes there seems to be a pattern in them), growing or diminishing rings of all kinds of color (I once read that these circles are also present in the retina of the non-yet-born, to provide some preparation), vague black-and-white faces, and many more, sometimes strange, sometimes for a short time recognizable forms.

So, what strange capers are the different light receptors, or neurons in or behind the retinas of my eyes performing?

# Answer
**Short answer**
Pressure phosphenes are believed to be induced by sensory neurons in the retina downstream from the photoreceptors due to stretch-mediated activation.

**Background**
You are referring to **pressure phosphenes**. They are visual perceptions induced by applying pressure to the eye ball. They are often described as a glow with arcuate or circular characteristics and are generally perceived in the visual field opposite to the area of pressure. If the object applying the pressure is small, the center of the perceived area appears light with a dark surround and a bright outer portion. However, there is substantial inter-individual variability in how pressure phosphenes are perceived (Chew *et al*., 2005).

Eyeball deformation leads to an activation of **ON-center ganglion cells** in the retina, while **OFF-center ganglion cells** are inhibited. It is thought that the activation of ON-center and inhibition of OFF-center ganglion cells by eyeball deformation are caused by retinal stretching, which may also lead to horizontal cell stretch. Stretching the horizontal cell membrane probably generates an increase in membrane sodium conductivity and a depolarization of the membrane potential. This depolarization of the horizontal cell membrane potential is transmitted either directly or indirectly (via receptor synapses) from the horizontal to the bipolar cells. The bipolar cells, in turn, can activate or inhibit the ganglion cells (Grüsser *et al*., 1989). Note that in this model, the photoreceptor cells in the retina are not involved - it occurs downstream in the secondary sensory neurons.

<sub>**References**
**-** Chew *et al*., *Eye* (2005) **19**: 683–5
**-** Grüsser *et al*., *Physiol Bohemoslov* (1989); **38**(4): 289-30</sub>
> 5 votes

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Tags: neuroscience, vision, neurophysiology
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# Question
Title: Have ideas of "gamification" been applied to education?
Wikipedia defines Gamification as "the use of game design techniques and mechanics to solve problems and engage audiences." Khan Academy has received attention (e.g., see this post) for incorporating some elements of gamification into its online learning system.

Are there any scientific papers that seek to:

* integrate the ideas of "gamification" into models of education and cognitive psychology?
* critically and empirically evaluate the ideas of gamification for educational purposes?

# Answer
> 12 votes
A popular lit review \[1\] discusses some game concepts that have been empirically tested to support the idea of gamification. In some cases, these may be very hard to quantify. For instance, the article cites *fantasy* as one gaming characteristic that engages gamers. Other characteristics, such as having *clear, well defined rules/goals* seem easier to objectify.

The authors also cite *mystery*, *challenge* (something hard but not too hard, with levels of increasing difficulty), *sensory stimuli*, and *user control* as important attributes as well.

\[1\] Garris et al. (2002). Games, Motivation, and Learning: A Research and Practice Model. Simulation and Gaming, 33, 441-467. Retrieved from http://scottsdale.brainadvantage.com/PDF/Games,%20Motivation,%20and%20Learning.pdf

# Answer
> 11 votes

# Answer
> 4 votes
Malone and Lepper (1987) is often cited as the seminal paper regarding gamification for education. They started off by identifying factors which affect computer game preferences and then identified motivational factors. Habgood et al (2005) built on this taxonomy and developed a high quality game for supporting the teaching of division. My understanding is that the key finding from that study is that the motivating factors should ideally be linked to the learning material.

Malone, T. & Lepper (1987). Making Learning Fun: A Taxonomy of Intrinsic Motivations for Learning. In Snow, R. & Farr, M. J. (Ed), Aptitude, Learning, and Instruction Volume 3: Conative and Affective Process Analyses. Hillsdale, NJ

# Answer
> 4 votes
I would also add this paper, which includes a critical discussion of the concept and proposes a working-definition for gamification in educational settings:

R. Rughinis, 2013, Gamification for productive interaction: Reading and working with the gamification debate in education

https://www.academia.edu/5758624/Gamification\_for\_Productive\_Interaction.\_Reading\_and\_Working\_with\_the\_Gamification\_Debate\_in\_Education

# Answer
> 2 votes
There are a lot of courses and literature about gamification in learning by Karl Kapp. http://karlkapp.com/articles/. Most of them are not scientific articles, but there are also books, courses and insturctions how to integrate these ideas. The topics you are asking for are partly discussed there.

# Answer
> 1 votes
*Punished By Rewards* by Alfie Kohn puts it in a behaviorist perspective, and extensively criticizes gamification inspired by operant conditioning. (here is a scientific article, a counter-argument to the book)

Daniel Pink's *Drive* puts gamification in a humanist perspective. See here.

T. Reiners, L.C. Wood (eds.), Gamification in Education and Business (2014), chapter 9, put gamification in the perspective of motivational and learning theories. This seems like the best (and most recent!) scientific answer to your question. The frameworks used are classic conditioning, expectancy-based theories and self-determination theory.

The authors of the specific chapter are Landers, Bauer, Callan and Armstrong.

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Tags: motivation, educational-psychology, gamification
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# Question
Title: What are ways to assess employability of workers?
Employability is typically defined as

> the continuous fulfilling, acquiring or creating of work through the optimal use of competences. (Van der Heijde & Van der Heijden, 2006)

One's employability does not only depend on one's ability to work (both physically and mentally), but also one's motivation to work and learn and the opportunity to work (Brouwers, 2012; dutch citation).

Especially for elders, who are getting older and older, and have to work longer (i.e. until a higher age), employability is becoming incredibly relevant. They need to be able (and willing) to keep on working until their retirement, either in their current position or another less demanding job. This is a difficult job without clear insights. However, with such an incredibly broad term, it will even be difficult to gain those insights.

Are there tools available to asses the personal factors of individuals' employability?

---

Heijde, C. M., & Van Der Heijden, B. I. (2006). A competence‐based and multidimensional operationalization and measurement of employability. Human resource management, 45(3), 449-476.

Brouwer, S., de Lange, A., van der Mei, S., Wessels, M., Koolhaas, W., Bültmann, U., ... & van der Klink, J. (2012). Duurzame inzetbaarheid van de oudere werknemer: stand van zaken. Universitair Medisch Centrum Groningen, Groningen: Rijksuniversiteit Groningen.

# Answer
Measures of *person-job fit* and/or *person-organization fit*. The following rather randomly assembled references are intended as links to some questionnaires.

## References

Chang, H.-T., Chi, N.-W., & Chuang, A. (2010). Exploring the moderating roles of perceived person-Job fit and person-organisation fit on the relationship between training investment and knowledge workers’ turnover intentions. Applied Psychology: An International Review, 59(4), 566–593.

Kooij, D. T. A. M., van Woerkom, M., Wilkenloh, J., Dorenbosch, L., & Denissen, J. J. A. (2017). Job crafting towards strengths and interests: The effects of a job crafting intervention on person–job fit and the role of age. Journal of Applied Psychology, 102(6), 971–981. https://doi.org/10.1037/apl0000194

Piasentin, K. A., & Chapman, D. S. (2007). Perceived similarity and complementarity as predictors of subjective person-organization fit. Journal of Occupational and Organizational Psychology, 80(2), 341–354. https://doi.org/10.1348/096317906X115453

Saks, A. M., & Ashforth, B. E. (1997). A longitudinal investigation of the relationships between job information sources, applicant perceptions of fit, and work outcomes. Personnel Psychology, 50(2), 395–426. https://doi.org/10.1111/j.1744-6570.1997.tb00913.x

Wheeler, A. R., Gallagher, V. C., Brouer, R. L., & Sablynski, C. J. (2007). When person-organization (mis)fit and (dis)satisfaction lead to turnover: The moderating role of perceived job mobility. Journal of Managerial Psychology, 22(2), 203–219. https://doi.org/10.1108/02683940710726447
> 2 votes

# Answer
One common tool to asses the personal factors of employability is the Work Ability Index (WAI; Tuomi, 1998). The WAI consists of 7 items, which contain one or multiple questions that have to be rated by the employee him-/herself. The items are:

1. Current work ability compared with lifetime best.
2. Work ability in relation to the demands of the job (both physically and mentally).
3. Number of current diseases diagnoses by a physician.
4. Estimated work impairment due to diseases.
5. Sick leave during the year.
6. Own prognosis of work ability two years from now.
7. Mental resources (consists of "enjoy daily tasks", "active and alert", and "full of hope for the future")

Especially item 7 concerns the psychological aspects of the employee, whereas items 1, 2 and 6 do rely on the employee's own judgement. The WAI thus focuses on personal aspects of employability, which, in part, are grounded in psychological sciences.

The WAI has shown to be sufficiently reliable (De Zwart, 2002; Radkiewicz, 2005) and, rather interestingly, is accepted in both the scientific community and is being used in the field (Brouwer, 2012)

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Tuomi, K., Ilmarinen, J., Jahkola, A., Katajarinne, L., & Tulkki, A. (1994). Work ability index. Helsinki: Institute of Occupational Health.

De Zwart, B. C. H., Frings‐Dresen, M. H. W., & Van Duivenbooden, J. C. (2002). Test–retest reliability of the Work Ability Index questionnaire. Occupational medicine, 52(4), 177-181.

Radkiewicz, P., Widerszal-Bazyl, M., & NEXT-Study Group. (2005, June). Psychometric properties of Work Ability Index in the light of comparative survey study. In International Congress Series (Vol. 1280, pp. 304-309). Elsevier.

Brouwer, S., de Lange, A., van der Mei, S., Wessels, M., Koolhaas, W., Bültmann, U., ... & van der Klink, J. (2012). Duurzame inzetbaarheid van de oudere werknemer: stand van zaken. Universitair Medisch Centrum Groningen, Groningen: Rijksuniversiteit Groningen.
> 1 votes

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Tags: measurement, io-psychology, human-factors
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# Question
Title: What to expect from a seriously mentally ill individual when a poor prognosis is revealed through improper channels?
I recently learned about a friend who is suffering from some serious mental illness from someone who has yet to reveal this illness to the individual. Apparently the individual in question suffers from Narcissistic Personality Disorder (NPD; and perhaps some other serious issues) and has very, very little chance for improvement through treatment as the prognosis is very poor according to the professionals. This is compounded by a likelihood that this individual is going to lose their children due to the circumstances of the situation.

My question is, statistically or experientially, what kind of a reaction can one normally expect from such an individual?

This person also, in the past, had an obsession with death and "murder scene" magazines. They also have lost someone very close through a family murder / suicide wherein a parent killed their entire family (spouse and children). This left an absolutely indelible impression upon this individual. This person also has a very reactionary and violent personality that tends to escalate issues that should be minimal. They frequently will become angered or even rage instead of having a normal weepy reaction to such stimuli that might cause a regular person sadness.

The reason I ask is that this person has children and I am extremely concerned about the manner that this news will be revealed to the individual. I would like to understand what kind of risk the children and their spouse (with whom they do not have a good relationship) are in.

Unfortunately I don't have any real power over the situation but to perhaps offer some suggestions and try to keep close (but safe) in order to keep the children out of harm's way. This has me very uncomfortable and worried as I don't have much power over the situation, but I would like to know potentially what to expect.

# Answer
> 2 votes
There is an answer to a similar question regarding narcistic behaviour and negative feedback reaction:

How can a narcissist be given negative feedback without triggering aggressive behavior?

It is a more general answer. The case you described has surely a lot more facets and details to consider. I would have just commented it, but I don't have enough reputation.

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Tags: abnormal-psychology, personality-disorder
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# Question
Title: What safeguards are in place to prevent abuse of power?
In the U.S., what safeguards are in place to prevent a mentally ill, or just spiteful or incompetent, psychiatrist / psychologist from abusing their position of power? Assuming the person is already practicing.

For example, are there any diagnoses that require an independent second opinion because of the serious consequences of acting on that diagnosis?

Obviously, this is especially important since- given the near complete power someone in this field could have over another person's life trajectory- the field will attract abusive people.

# Answer
As @ArnonWeinberg mentioned, clinical supervision, detailed in my answer to the previous question will prevent abuse of position.

Clinical supervisors have a duty of care, not only to the supervisee (the therapist), but also the supervisee's clients, and if the supervisor feels that abuse of power is occurring they must refer it to the governing bodies to remove their licence to practice.

If they feel there are any mental health issues preventing the supervisee from acting effectively, then the supervisor will refer the supervisee for therapy. If necessary, they may also take further action to prevent the therapist from causing harm to their clients whilst undergoing therapy. I have added this point to my previous answer mentioned here.
> 2 votes

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Tags: clinical-psychology
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# Question
Title: What is the capacity of the human brain?
What would a reasonable estimate be of the data capacity of the human brain expressed in bytes?

# Answer
Paul Reber, professor of psychology at Northwestern University, stated that

> The human brain consists of about one billion neurons. Each neuron forms about 1,000 connections to other neurons, amounting to more than a trillion connections. If each neuron could only help store a single memory, running out of space would be a problem. You might have only a few gigabytes of storage space, similar to the space in an iPod or a USB flash drive. Yet neurons combine so that each one helps with many memories at a time, exponentially increasing the brain’s memory storage capacity to something closer to **around 2.5 petabytes**.

1PB = 1,000,000,000,000,000 B = 1015 bytes = 1000 TB (terabytes).
1TB = 1,000,000,000,000 bytes = 1012 bytes = 1000 GB (gigabytes). So
2.5PB = 2.5 million gigabytes

> For comparison, if your brain worked like a digital video recorder in a television, 2.5 petabytes would be enough to hold three million hours of TV shows. You would have to leave the TV running continuously for more than 300 years to use up all that storage.

The same article states that although it is stated that the brain is capable of storing around 2.5PB of information,

> The brain’s exact storage capacity for memories is difficult to calculate. First, we do not know how to measure the size of a memory. Second, certain memories involve more details and thus take up more space; other memories are forgotten and thus free up space. Additionally, some information is just not worth remembering in the first place.
> 8 votes

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Tags: theoretical-neuroscience, brain
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# Question
Title: What is the leading alternative to the "stages" model of grieving?
In "Cautioning Health-Care Professionals: Bereaved Persons Are Misguided Through the Stages of Grief" by Stroebe et al. the popular "5 stage model" of Kübler-Ross is incorrect. Stroebe et al. argue:

> the regularities of stage theory are too simplistic and limited; they fail to represent the complex emotions and processes of grief and grieving. They also lack empirical foundation. Using stages in practice is potentially harmful, and yet an (perhaps the) ultimate goal of theory construction in our field is to enable health-care professionals to provide tangible help to those who need it.

What are the leading theories/models of bereavement and how are they superior?

# Answer
According to "Theories of Grief and Bereavement" by Boerner et al. (2015) the leading theories are:

* The Four Component Model from Bonanno and Kaltman

1. Context in which loss occurs
    2. Subject meanings associated with loss
    3. Changes in representation of the lost loved ones over time
    4. Presence of coping and emotion processes
* The Dual Process Model from Stroebe and Schut

1. Loss-oriented coping
    2. Restoration-oriented coping

The article also notes that further work needs to be done in terms of:

* Effects of inter-personal relations
* Influences of cultural background
* Biological aspects
> 2 votes

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Tags: social-psychology, reference-request
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# Question
Title: Validity of limerance as a romantic evolutionary stage
I was looking into the concept of limerence as a stage of evolution in a romantic relationship, however I can't find any sources for it other than its origin in the book "Love and Limerence: The Experience of Being in Love" by Dorothy Tennov. Has there been any criticism of this as a concept, not as diagnosis for abnormal psychology? I'm somewhat skeptical of any psychological concept put forth by a single part without external validation.

# Answer
The theme of love is and will be a very broad subject in psychology. As on other occasions I have always focused on variables to take into account in this theme: attachment, attraction, sexual behavior, esthetics (philosophical theme), likes, interests, etc (as always keep in mind also that there may always be more variables than those considered).

In broad themes:

* Certain facts can be studied as phenomena.
* A set of facts about a phenomenon can be established in a construct in a theory (here it is not so much about terms or concepts) these constructs have different realities (reality as individual mental state, reality through the influence that causes In the social or interpersonal domain), can not be directly observed, its characteristics must be studied through other objects.
* In many cases it is difficult to limit the construct due to its limits, for example other processes or even other social phenomena (for example, how to determine the limit of the stereotype construct in any investigation).

Addressing the issue of validity in a broad sense (beyond validity in psychometry) (epistemological validity) can refer to many things, to perform a certain analysis, to apply a methodology, a hypothesis, an experiment, at in the end can be understood as the correct scientific procedure.

The term limerance has validity in that it is a concept that refers to a construct whose effects are registered by an investigator and seem to be found other sources that handle it (it is not strictly necessary for the construct to be labeled in this way in other sources , It does not matter as much the sources as the methodological validity of the scientific process, in any case if that seems to be a construct that other investigators handle)

Further reading:
> 1 votes

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Tags: social-psychology
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# Question
Title: Apart from sleep, does the brain needs rest?
I am a graduate student in CS, and naturally, I take several breaks a day from studying, but I feel that most of those breaks are habit-influenced and that I do not absolutely need to get off my seat and meditate, exercise, etc. For instance, I love reading/learning philosophy, but because I am aware that such a practice requires non-trivial brain effort, I only do that on vacations and I find myself disinclined to attempt such a thing on those breaks. However, I think that this disinclination stems from *my awareness* of the non-triviality of the undertaking and essentially *my laziness or mental fatigue*, *not from natural brain-related issues*.

> Is there documented evidence that the brain needs regular periods of rest in certain individual-dependent amounts, apart and *in addition* to the normal ~8 hours of sleep?

# Answer
> 2 votes
Margarita Tartakovski on PsychCentral says,

> Information is merely a click — or, more accurately, a Google search — away. Depending on your query, there’s likely at least a dozen, if not hundreds, of blogs on the topic, a similar number of books and many more articles.
>
> This is a good thing, but it also can overburden our brains.
>
> According to Lucy Jo Palladino, Ph.D, a psychologist and author of Find Your Focus Zone: An Effective New Plan to Defeat Distraction and Overload, “Information overload occurs when a person is exposed to more information than the brain can process at one time.”
>
> Alvin Toffler actually coined the term in 1970 in his book Future Shock. As more and more people started using the Web, “information overload” became a popular phrase to describe how we felt about going online, Palladino said.
>
> According to neuroscientists, the more accurate term is “cognitive overload,” she said. That’s “because the brain can process vast amounts of information depending on the form in which it’s presented,”

According to Professor Torkel Klingberg, MD, PhD (2009), the brain can suffer from information overload, and he gives some examples of what he is talking about.

> Our brains have limited capacity for processing information. This book is an attempt to understand why this is so, what effect it has on our everyday lives, and how we can stretch these limits with mental exercise......In his article "Overloaded Circuits: Why Smart People Underperform," psychiatrist Edward Hallowell coins the term "attention deficit trait" to characterize the situation.

From these articles, and articles linked within these articles, I would say that there are times that **the brain needs rest at times in-between mental activities, in order to process things learnt, but the periods of rest needed can vary depending on how the activity taxes the brain, and how much it is used to dealing with the information**.

# Answer
> 1 votes
The brain needs rest as much as it needs stimulation and exercise. The line has to be drawn, however, where one feels as if *too* much rest is given. If the brain continuously is computing, organizing or analyzing complex problems 24/7, may start to degenerate. There is only *so much* our brain can do without rest. According to the book **Brain Facts: A Primer on the Brain and Nervous System**, lack of sleep stretches far beyond increased vulnerability to diseases and health complications. It encompasses, but isn't limited to:

* slowed neuroplasticity
* general cognitive impairment implicated in the frontal lobe
* decreased *long-term potentation* which is important for higher cognitive function.

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Tags: cognitive-neuroscience, training, mental-exhaustion
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# Question
Title: Pleasure can be implicated in a chemical reaction in the brain, but does this really affect the intensity of the feeling?
It is true that many, if not all feelings of our mind like euphoria, dysphoria, pleasure, sadness *et cetera* are linked to a chemical reaction in our brain. This reaction is essentially what *causes* us to feel these emotions.

However, is the factor that causes us to really ***feel*** what we feel inherently biochemical? If so, then what neurobiological property of these reactions causes the intensity of the feeling? For example, what separates plain happiness from blissful ecstasy?

# Answer
> 1 votes
**Short answer**
In case of dopamine, its amounts present in the reward pathway in the brain correlates positively with the intensity of pleasure experienced.

**Background**
To focus the answer I'll narrow the scope of this post to one of the most extensively investigated emotional centers in the brain, namely the reward center involving the **dopaminergic mesolimbic pathway**.

Dopamine (DA) release in this system rewards the brain's host for beneficial things essential to life, such as eating, drinking and having sex.

It is also one of the major neural centers in the brain involved in addiction, including nicotine, cocaine and methampetamine addiction, as well as gambling and pathological risk-taking behaviors.

The opiate class of narcotics, most notably cocaine, amphetamine, methamphetamine, morphine, heroine and their analogues invoke a massive increase in DA levels in the mesolimbic pathway. An increase in DA levels has been shown to be a final (secondary) common pathway that mediates the rewarding properties of these drugs of abuse, explaining their addictive properties (Chiara & Imperato, 1988).

In humans it has been established by behavioral experiments that the magnitude of ventral striatal DA release (the striatum is a part of the reward system in the brain) correlates positively with the hedonic (pleasure) response associated with amphetamine (Drevets *et al*., 2011). In other words, **more DA is correlated with more happiness** and thus the amount of DA indeed correlates with the intensity of the feeling associated with its release in the reward system.

As a side note on this; a notorious problem with many drugs of abuse are their purity. For example, Coca leaves cause a mild stimulant high when chewed. As far as I know, the American Indians have not suffered from overt physical or psychological dependence on these leaves in the thousands of years they probably have used them. However, shortly after the discovery of coca leaves (and opium poppies for that matter) by the Old World, the active ingredient was purified and eventually isolated. Cocaine (and morphine) cause a sudden and massive increase in dopamine levels (Romach *et al*., 1999), in turn not just leading to feelings of pleasure, but to near-instantaneous, full-blown ecstatic **euphoria**. It is this notorious '*first-time high*' that virtually every addict keeps on pursuing, and which they will unfortunately never experience again in their life due to tolerance that build up almost instantly after first use of highly purified preparations of coca (crack, cocaine) and poppies (morphine, heroine).

*Post scriptum*
In general, the '*biochemistry*' of the brain refers to neurotransmitters. Their actions are primarily due the binding of these compounds to their respective receptors. The process of neurotransmitter release and receptor binding are not *chemical reactions* in the strictest sense of their meaning, as stated in your question. The secondary responses of the postsynaptic neuron may, or may not involve chemical reactions. Some second messenger systems do rely on chemical reactions (the metabotropic receptors including the dopamine receptors) while others do not (ion channel-coupled receptor systems for example).

**References**
**-** Chiara & Imperato, *PNAS* (1998); **85**: 5274-8
**-** Drevets *et al*., *Psychiatry* (2001); **49**: 81–96
**-** Romach *et al*., *Arch Gen Psychiatry* (1999); **56**(12): 1101-6

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Tags: neuroscience, emotion, neurophysiology, neuropsychology
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