# Question
Title: How much of brain power consumption is for information
As previously answered on this site, the brain uses 20W of power. However, how much of this power consumption is for information processing and how much of it is for maintenance of biological conditions for information processing, such as temperature regulation?

# Answer
> 1 votes
According to "Tightly coupled brain activity and cerebral ATP metabolic rate" which is summarised in the Scientific American article "Why Does the Brain Need So Much Power?", conscious computation accounts for 50% of the brain's power consumption. From the Scientific American article:

> Chen and his colleagues used MRS specifically to track the rate of adenosine triphosphate (ATP) production, the primary source of cellular energy, in rat brains. MRS employs a magnetic resonance imaging (MRI) machine programmed to pick up particular elements in the body—in this case, the three phosphorus atoms in each ATP molecule...
>
> The team noted that when the lab rats were knocked out, they produced 50 percent fewer ATP molecules than when they were mildly anesthetized.The ATP produced when the brain is inactive, says Chen, seems to go mostly toward cell maintenance, whereas the additional ATP found in the more alert animals fueled other brain functions. He speculates that only a third of the ATP produced in fully awake brains is used for housekeeping functions, leaving the rest for other activities.

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Tags: neuroscience, theoretical-neuroscience
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# Question
Title: What's the feeling where you feel weird in places where people in movies get stabbed etc
For example in the matrix, when the little bug crawls through his belly button my belly button feels weird.

# Answer
What you are describing seems to be a form of mirror touch synesthesia

> Mirror-touch synesthesia is a condition which causes individuals to experience the same sensation (such as touch) that another person feels. For example, if someone with this condition were to observe someone touching their cheek, they would feel the same sensation on their own cheek. Synesthesia, in general, is described as a condition in which a stimulus causes an individual to experience an additional sensation. Synesthesia is usually a developmental condition, however recent research has shown that mirror touch synesthesia can be acquired after sensory loss following amputation.
> 1 votes

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Tags: cognitive-psychology
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# Question
Title: Do studies exist that can map specimens of neocortex to the functions they perform(ed) in vivo?
Much brain research has proposed that the brain (the neocortex, esp.) is set up in areas - an area for faces, an area for language, etc..

The experiments typically go 1) damage an area 2) observe what function is lost. And this has produced a good deal of evidence that behavior ends up being localized. But for me, this information is incomplete, especially in the light of studies that show that every part of the cortex does essentially the same thing!

Has anybody ever done a study where, looking at tiny areas of neocortex, scientists can identify a) what information it contains b) what it does, or c) from what part it came?

# Answer
> 2 votes
> ...studies that show that every part of the cortex does essentially the same thing!

I would be much interested in seeing these studies - Although the brain is plastic and inter-individual differences can be substantial, it is generally accepted that functional regions are well defined in terms of their anatomical locations and **brain mapping** was, and still is, a field of research in its own right.

Studies where

> tiny areas of neocortex \[were studied\]

have been done, and showing

> what it does

Notable examples include singe-unit recordings (cellular level - as tiny as you can get) that mapped the primary visual cortex (V1) and auditory cortex (AI). Such studies have shown that V1 contains retinotopic maps, and AI contains tonotopic maps, *i.e.,* these studies showed that each region in the retina projects to a well-defined and neatly organized region in V1 (*e.g*., Cowey, 1979), and well-defined anatomical locations in the cochlea project to well-defined and well organized regions in AI (*e.g.*, Ozaki & Hashimoto, 2007).

> what information it contains

is hard to answer, as the brain is not a hard disk that can be read back. However, studies on Alzheimer patients do reveal that old memories are often relatively spared, while new ones fail to be stored properly, indicating indirectly what information the affected cortex contains.

<sub>**References**
**-** Cowey, *Quarterly J Exp Psychol*; **31**(1): 1-17
**-** Ozaki & Hashimoto, *Can J Neurol Sci* (2007); **34**(2): 146-53</sub>

# Answer
> 2 votes
I wanted to make a few additions to Christiaan's answer. First of all, the functional location's as described by Brodmann (wiki) is a little outdated. Nowadays, it is believed that there are networks of regions that are responsible for a particular function. An example is the default mode network, a network of the ACC and prefrontal regions, that is associated with self-generated thought or mind-wandering (, ).

There is also another line of research that focuses on functional location: Trans-cranial Magnetic stimulation (TMS). With TMS you stimulate the brain with a strong magnetic field, therewith (de-)activating a particular area of the brain for a short period of time. If you would stimulate a part of the motor cortex, you could, for instance twitch someone's arm. Or, if you would stimulate parts of the visual cortex, you could temporarily cause (color-/movement-) blindness. If you search for TMS, there are plenty of other examples.

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Tags: neuroscience, reference-request, neurophysiology
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# Question
Title: Are there any cognitive tests, or test suites, available on the Android?
Are there any cognitive tests, or test suites, available on the Android? I'm thinking something like quantified-mind.com but for android. The closest I've been able to find is Brainturk Brain Training, but there doesn't appear to be a way to export results.

It's similar to this question, but for the android: Are there any cognitive test (or test suites) available on the iPad?

My 4 main criteria are (like here):

* app should simply measure cognitive or mental skills/abilities, as opposed to training or improving them measurement methods used in the
* app should be as close to scientific as possible (a lot of game apps failed this requirement)
* the tests should take as little time as possible (preferably under 5 min)
* have a way to export data (e.g. into csv)

# Answer
> 3 votes
The N-back task is a typical test for cognitive capabilities. There are many version of it in the Google play store. You could try a few of them and see which suits your needs best.

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Tags: cognitive-psychology, measurement, test
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# Question
Title: Implementation of Bayesian inference on cognitive science research question
To clarify, I am not talking about Bayesian model of cognition. That model refers to the theory that the human learning and inference approximately match Bayesian inference reasoning. (The two topics are not unrelated though).

What I am talking about is the choosing of one hypothesis over another in explaining sets of data obtained. I recently read this paper (Jefferys & Berger 1992) that applies Bayesian inference to quantitatively explain Ockham's razor (the rule of thumb that simpler hypotheses are better).

Here is the link to the article: http://www.jstor.org/stable/29774559

**Bayesian inference description**

In the paper, the author implemented Baye's theorem to calculate the probability of a hypothesis being correct when new data is presented. The equation is as follows:

Where $P(H\_i|D\\&I)$ is the probability of a certain hypothesis being true given prior information (I) and new data (D). $P(D|H\_i\\&I)$ is the probability of new data (D) occurring given prior information (I) and the hypothesis being true (Hi). $P(H\_i|I)$ is the prior probability ascribed to the hypothesis (Hi). $P(D|I)$ is the probability of new data (D) occurring given prior information (I) no matter whether the hypothesis is true.

In the paper, the author applied the Bayesian inference to show how data given for each trial can lead to weighing of one hypothesis vs another.

The example he gave compared two hypotheses: 1st hypothesis (H1) states that the coin has one head and one tail. 2nd hypothesis (H2) states that the coin has two heads. Initially, probability of each hypothesis being true is likely (there has not been a coin flip, and the experimenter does not know the coin at all). Thus, $P(H\_1|\emptyset) = P(H\_2|\emptyset) = 0.5$.

1st trial occurs, and the coin lands head. The probability of each hypothesis is modified.

For 1st hypothesis (1 head 1 tail), $P(Head|H\_1\\&\emptyset) = 0.5$, $P(H\_1|\emptyset)=0.5$, and $P(Head|\emptyset)=unknown$. Thus, $P(H\_1|Head)=\frac{0.25}{P(Head|\emptyset)}$.

For 2nd hypothesis (2 heads), $P(Head|H\_2\\&\emptyset) = 1$, $P(H\_2|\emptyset)=0.5$, and $P(Head|\emptyset)=unknown$. Thus, $P(H\_2|Head)=\frac{0.5}{P(Head|\emptyset)}$.

$P(Head|\emptyset)$ is normalization factor, and we are only comparing two hypotheses. Thus, $P(H\_1|Head) + P(H\_2|Head) = 1$. Thus, $P(H\_1|Head) = 1/3$ and $P(H\_2|Head) = 2/3$.

Flipping the coin multiple times and getting head each time decreases $P(H\_1|Head)$ while increasing $P(H\_2|Head)$ to near 1.

**Applications to cognitive science and specifically neuroimaging or EEG**

I found this method of hypotheses weighting to be very insightful and was wondering if there were applications of Bayesian inference to cognitive science in determining one hypothesis over another. Examples on neuroimaging or EEG data processing would be preferred since I am interested in that field, but any other example would be a good starting point.

# Answer
> 2 votes
A good starting point is probably Alex Etz's Understanding Bayes blog post series. He also co-authored a related paper that should be a great starting point: How to become a Bayesian in eight easy steps: An annotated reading list (link is to pre-print).

Richard Morey's BayesFactor blog is great resource for understanding the Bayesian model comparison approach. He has authored many papers that are relevant, but the blog is the best starting point for learning about the approach.

For a really accessible textbook, John Kruschke's Doing Bayesian Data Analysis is an excellent and thorough treatment of the use of Bayesian parameter estimation in data analysis. This approach is a bit different from the model comparison approach, but the conceptual ideas are the same. A related paper that motivates the approach in the book is available here.

# Answer
> 0 votes
Bayesian model comparison is widely performed. Here's a recent invasive electrophysiology example on decision-making:

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Tags: data
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# Question
Title: Applying signal detection theory to single-stimulus presentations
Normally, signal detection theory (SDT) is applied to data that involves giving two-alternative forced choice (2AFC) responses to pairs of stimuli, for instance saying whether stimulus B was the same or different from stimulus A.

I am wondering if SDT can also be applied to such judgements being made of single-stimulus presentations, particularly ones for which the "correct" answer is not necessarily objectively-determined, such as, for instance, seeing a visual stimulus and deciding whether it belongs to category A or category B.

# Answer
> 5 votes
There are a huge number of paradigms that SDT can be applied to. The simplest is probably the so-called yes/no paradigm. You present a single stimulus (typically noise alone or signal plus noise) and ask was the signal present. The subject if forced to respond with either yes or no. This type of paradigm typically leads to a response bias. In a 2-interval, 2-alterantive, Forced-Choice (2I-2AFC) paradigm both a noise alone stimulus and a signal plus noise stimulus are presented in random order. Subjects are then forced to to respond if the signal was in the first or second interval. The randomization tends to reduce (but not necessarily eliminate) the response bias linked to the stimulus (subjects may respond first more often than second, but they will be randomly allocated to noise and signal plus noise trials). One can both increase the number of intervals and/or the number of responses. For example a 1I-3AFC paradigm might involve responses of red, green, or blue. A typical 3I-AFC is the AXB paradigm. Confidence rating paradigms also fall within the scope of SDT.

Without objective definitions of the "noise" and "signal plus noise" categories, it is not possible to define a *hit* or a *correct rejection*. As hits and correct rejections are the basis of SDT, it is not clear if SDT will be useful.

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Tags: signal-detection, psychophysics
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# Question
Title: How to compare tasks completed by neural architectures objectively?
When I first saw this video of Spaun and the tasks it can complete (solving the Towers of Hanoi problem, completing the Raven matrices), I was really impressed, but then I realized I didn't really know what other tasks were being completed by other neural architectures. Consequently, I almost asked a question here that was basically "How does Spaun compare in terms of task complexity to other neural architectures?". However, I realized that it would be better to if I could learn how to do this evaluation myself.

So, what metrics or heuristics can be used to evaluate the complexity of a task completed by a neural architecture? How can one evaluate the complexity of a problem/puzzle such at the Tower of Hanoi, to another problem, such as modelling how people solve algebraic equations, like ACT-R has accomplished?

# Answer
More than two years later, I now have a heuristic (which is a close as I can get to an objective metric) that I rely on. As I write about in one of my blog posts, there are a couple of tasks that humans are capable of that are still really hard for machines. They require the following things for a machine (or a neural model):

* **Balancing Planning and Exploration:** Modelling the environment's future state and the possible future states via exploration efficiently.
* **Scaling Skills:** Transfering skills between tasks and building more complex skills atop of basic skills.
* **Knowledge Representation:** Keeping relations between skills, environmental variables, past knowledge and priorities all usefully organised.

Any neural model that begins to leverage these things is evaluated as impressive in my eyes.

However, these requirements are mostly for Artificial Intelligence. What about neural models specifically? All neural models that complete a task are, by definition, cognitive models, so in addition to the above criteria they must satisfy various Cognitive Criteria to prove the system is achieving it's goals in a human-like manner.
> 1 votes

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Tags: theoretical-neuroscience, computational-modeling
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title: Social loafing vs. Free riding

text:
# Question
Title: Social loafing vs. Free riding
In different papers I see these terms with very close definitions. Are they different things? If yes, how one can differentiate them?

# Answer
> 5 votes
You are correct in that these terms are very close in definition, but terminology is not just about identifying a concept. Terminology is also about identifying the perspective from which you will look at the concept and the community to which you, as the researcher, belong. Here, free-riding and social loafing have very different histories.

Social loafing comes from the social psychology literature and is most closely associated with the methods and typical explanations of that field. Thus, you will typically encounter social loafing around discussions of motivation, diffusion of responsibility, and feeling of effort as dispensable.

Free-riding comes from the economics and game theory literature and is most closely associated with the models and methods of those fields. Thus, you will typically encounter free-riding around discussions of cost-benefit analysis, rational choice, and (the paradox of) cooperation.

The only difference in concept (that I know of) comes from the economics focus on rationality. Social psychologists would classify as social loafing situations where the 'slacking' of an individual hurts not only the group, but their own performance as well (they would have individually -- not just as a group -- gotten a higher payoff if they didn't slack). On the other hand, economists, would not consider this as a case of (rational) free-riding, since they reserve that word for social dilemmas where cooperating costs you more than the marginal increase you get from the benefit to the group, but where everybody free-riding is even worse.

Of course, the terms cross-fertilize, especially in the direction of free-riding entering the discussions of social loafing. In the social psychology literature, you will see free-riding used as an *explanation* of social loafing in cases where the experimenters believe that the choice to loaf is based on a (rational) cost/benefit analysis instead of some of the other factors I discussed.

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Tags: social-psychology, terminology, experimental-psychology, motivation, game-theory
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# Question
Title: Could physically simulating neural structure on a fundamental level yield superior results to machine learning algorithms?
My curiosity is merely of whether (in a future where we have computers with the processing power of the human brain) it's possible that actually simulating a neural network's physical *behavior* on the most fundamental level might be more effective than using algorithms to reach the same result.

I'm hoping for an answer which argues this topic on a purely fundamental level.

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Is it likely (or not) that we might achieve a superior (more efficient, more intelligent, more dynamic) result by simulating the advanced behavior of neural interaction (the neuro-activity patterns the brain experiences to form emotions, develop conclusions, processes sensory data, establish and/or revisit memories, etc) than we can reach by using shortcuts (advanced machine learning algorithms, etc)?

# Answer
> 3 votes
Very interesting question. Although I have not a single little bit of expertise in this area, I do have some references you may want to read. First is a paper by Merz and Fromherz (2005) where they grew snail neurons on a silicon chip. Pfister et al (2007) also tried to grow neurons to allow interfacing between neurons and machine (for neural prosthesis e.g.). There is thus definitely a field of research that believe neural interfacing may be better than mechanical and algorithmic networks.

There has been 10 years worth of research since these papers so I bet there are some advancements that may give you a more definitive answer than mine.

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Tags: artificial-intelligence
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title: Why does clickbait use numbers?

text:
# Question
Title: Why does clickbait use numbers?
Around the Internet, especially in social media, we see examples of hyperlinks in a common format that has been cynically dubbed "**click bait**" or "**link bait**".

The idea is that authors publish these links with evocative titles, trying to entice a casual browser into clicking the link and viewing the content (where the resultant loading of the advertisements presumably earn some small amount of money for the content provider).

Some examples of click bait (with links removed, to protect everyone's sanity) are:

> * Watch out, these **15** baby penguins are waddling off to steal your heart.
> * **31** creative life hacks every girl should know
> * **20** Powerful D-Day Photos On The 70th Anniversary Of The Invasion
> * **11** Sexy Star Wars Tattoos

Many of these kind of links use provocative phrasing, like "you won't believe" and "will shock you". I can see intuitively why this works to entice people to click the link.

What is the reason for giving a number, like in the examples? Is there any psychology involved in this trend?

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This question comes from someone who doesn't really know anything about psychology or cognitive science; I'm just interested.

# Answer
> 4 votes
Digital Marketing often produces 'content' for users to consume. That content is ment to catch and keep the attention of the user, in an attempt to make the user trust and follow the sender (usually a website or blog). When the user shows engagement like clicking the right buttons, the user will somehow be tempted with some kind of offer (a newsletter, a free ebook, etc). If the user takes that bait, there will later be an offer to actually buy something.

The whole idea here is to catch and keep the users' attention. One of the most common ways to achieve this, is by making lists of something the user might want to read\see. In order to have users click(open) the content to begin with, the writer needs to make the content seem valuable in only 1 short line. By typing the number of entries on that list, the writer is trying to make a point: There's stuff to see her, come check it out!

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Tags: social-psychology, motivation, attention, internet, consumer-psychology
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# Question
Title: Provable ROI for call center rest periods?
Think you can help make life better for a nation of call center workers?

At a large insurance company, I used to work in the call center for both Auto Claims and then Homeowner Claims, before I was promoted on to other things. It's a complicated and stressful position, where customers are already upset because they have just gotten in a car accident or their house just burned down.

Call volume varies, but tends to be constant during many busy periods. As soon as you're done with one call, sometimes there's a lull, but usually another call is waiting.

**The problem is** that this leads to people taking a breather during "After Call Work," purposefully inflating their call time in order to catch a break from the stressful calls.

**A potential solution**, I've always wondered, is to pre-program an automatic break of no calls for X minutes after Y calls. (e.g. a 1 minute break after every 3 calls.)

**My question** is, would there be any scientific basis that could help justify a Return On Investment? Is a rest period worth the drain on phone coverage? Or is it more beneficial to leave it up to the workers, to sacrifice their Average Handling Time at will to decompress at their own pace?

# Answer
This is the paper you would want to read on this topic. The paper empirically compares four modes of managing interruptions. It is a great (and long) read so I'll try to summarize the bit for you:

There are thus four modes of managing interruptions:

* Immediate interruptions. There is no management whatsoever. As soon there is a distracting stimulus/task, it has to be attended to. In your case, you could think of being in a conversation with one costumer and immediately being switched to another. You can already imagine this is not a very good one.
* Negotiated interruptions. You can decide all by yourself whether and when to attend to the interruptions. You could choose to finish a difficult part of one task and only attend to the interrupting task when that is done.
* Mediated interruptions. Some other metric decides when an interruption is deemed appropriate. A well known metric is workload, as measured by pupil dilation. To bigger you pupil is, the higher workload is. Interrupting would be best in low workload situations (Salvucci and Bogunovic,2010)). What you suggested, the cooldown time, is also a mediated system.
* Planned interruptions. Interruptions only come at moments you have planned. Though this may seem nice, in many situations, such as yours, this is not possible. Even if you could plan the moments, in dynamic environments you cannot predict the best moments. You could have an incredible high workload on one day, and have nothing to do on another.

## So which is best?

The results show that the best interruption management systems are a combination of negotiated and mediated management (believe me on this one, I do not want to discuss 20 pages of results here haha). Mediated management systems will determine the best moments of interruptions which is incredibly useful. However, if workload is very high for a longer period of time, the callers may be on hold for too long.

The negotiated management of interruptions allows people to work as hard as they can/want. Some people perform better under pressure than others and may choose to wait for a shorter period of time. The downside, however, is the fact that people are bad at this. Some people stress themselves out and never wait (Asking for reference here) and some people wait to long and may get distracted by other things (Katidioti et al.,2014).

A combination would thus be best. Mediate the interruptions, but allow the employees to continue working when they want to. In you case, you could have a short mandatory pause duration and a suggested longer pause duration (or conversely, an maximum pause duration). You could then determine the duration of the pause based on the length of the last call(s) for instance.

I hope this answers your question and if you have any questions just let me know.

EDIT: The literature I described above mainly focuses on multitasking, while your question is about sequential tasking. Nevertheless I do believe the above can be generalized to your problem. The interruptions are now in fact the breaks.

A final note, if people purposefully inflate there call time, this may be an indicator that workload is indeed too high. Talk with the people and ask what they think of the situation and what they think may be a good solution. When changing an interface/task/process, people accept the changes much more quickly if they are involved in the process (Asking for reference).

*References:*

Daniel C. McFarlane (2002): Comparison of Four Primary Methods for Coordinating the Interruption of People in Human–Computer Interaction

Salvucci and Bogunovic (2012): Multitasking and Monotasking: The Effects of Mental Workload on Deferred Task Interruptions

Katidioti and Taatgen (2014): CHOICE IN MULTITASKING: How delays in the primary task turn a rational into an irrational multitasker
> 4 votes

# Answer
Taking a break at work wards emotional job-burnout and can also led to job satisfaction, and a greater effort at job tasks. Of one in five of the half of U.S. employees (10%) work a full-time 60+ hours a week (2014 Gallup poll, 2014), one in five of these employees (2%) taking lunch breaks (Right Management, 2012). Employees may take up to 2 breaks a day, feeling more energized and motivated from a morning break, and are more productive throughout the day.

Source: http://news.health.com/2015/09/18/workday-breaks-help-employees-reboot-researchers-say/
> -2 votes

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Tags: reference-request, motivation, performance, io-psychology, stress
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# Question
Title: How can Semantic Pointer Architecture be used to capture dynamical systems?
Most uses of SPA I've seen seem to be representing static systems, such as recognizing digits, categorizing images, rapid variable creation (also called "completing a pattern") and planning a path for writing those digits back out. Can it be used to represent dynamics as well, such as the general movement from a series of images?

# Answer
As explained in the NEF book, all non-linear dynamical systems can be represented in the NEF.

The SPA is simply applying semantic meaning and manipulations to the vectors represented by the NEF. The two most prominent examples of this are the motor system and the inference system in Spaun, which are shown in the aforementioned "rapid variable creation" task.

The vision system represents symbols (numbers) which get sent to the inference system. The inference system figures out the answer and sends it to the motor system. The motor system converts the symbol to a path and follows it.

Adding dynamics in a similar system with dynamics being visually identified, manipulated and then output, instead of static paths. One could imagine a system where the dynamics of the movement of an object are identified, manipulated neurally and then imitated. For example, having the running of a cheetah represented a series of limb movements, mapping them onto the human body and then having a human imitate that gait.

Of course this hasn't been implemented yet (and would look quite silly), but it shouldn't be super difficult. The main problem would be a good "demo" or psychological data to match, but I think this is still a good example.
> 1 votes

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Tags: theoretical-neuroscience, cognitive-modeling, spa
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# Question
Title: Is the split-brain, dual consciousness experiment from Rhawn Joseph valid?
I have been reading about the problem of possible dual consciousness in split brain patients and I came across this wikipedia page.

In the "other experiments" section, the two last paragraphs about Joseph's experiments seemed extremely simplistic, too obvious to be true. The way they are described and how groundbreaking it would be if true: two consciousness living in one brain and fighting with each other. So I decided to google the name of this Jospeh Rhawn. You should judge by yourself: http://rationalwiki.org/wiki/Rhawn\_Joseph is the first link showing up. It is clearly a crackpot. Although he managed to get published how can you trust this guy about the split brain experiments? After reading a lot about the subject I thought they were extremely weird. Any expert who could give an advice about the experiments and the guy?

# Answer
**Short answer**
On the basis of a cursory literature review, I conclude that Jospeh's observations were correct, but his conclusions that a callosotomy can result in a dual consciousness were far stretched.

**Background**
First off, I'm not an expert on this topic, but I will give my referenced opinion anyway, as there is no answer yet to this question; Below are quoted the two sections from the wiki **Dual consciousness (neuroscience)**, as linked in the question:

> Rhawn Joseph observed two patients who had both undergone a complete corpus callosotomy. Joseph observed that one of the patient’s right hemisphere is able to gather, comprehend, and express information. The right hemisphere was able to direct activity to the patient’s left arm and leg. The execution of the left arm and leg's action as was inhibited by the left hemisphere. Joseph found that the patient’s left leg would attempt to move forward as if to walk straight but the right leg would either refuse move or begin to walk in the opposite direction. After observing the struggles of the execution of activities involving the left and right arms and legs, led Joseph to believe that the two hemispheres possessed their own consciousness.\[16\]
>
> Joseph also noted that the patient had other specific instances of conflict between the right and left hemispheres including, the left hand (right hemisphere) carrying out actions contrary to the left hemisphere's motives such as the left hand turning off the television immediately after the right hand turned it on. Joseph found that the patient’s left leg would only allow the patient to return home when the patient was going for a walk and would reject continuing to go for that walk.

First thing to note - he describes two patients and only one of them is highlighted on the wiki; hence, this is a **case report** (Joseph, 1988). Case reports can't control for any other personal characteristics of that one patient. Such anecdotal reports are important, but they may not be a reflection of the population as a whole (i.e., people with a transected corpus callosum).

Secondly, the term 'consciousness' is a loosely defined and debated one. Similarly, the 'mind' is a broad and ill-defined term.

Then you proceed to scrutinize his work as based on his unconventional beliefs on the origin of life as based on a rational wiki page. Although his ideas on this may be unconventional, that doesn't mean he has reported flawed observations during his professional career as a neuropsychologist.

However, and I quote a part of the Discussion section of Joseph (1988) where he describes anecdotal behaviors of 2-C:

> \[He\] became angry with his left hand, swore and expressed "hate" for it, struck his left hand/arm with his right hand, and engaged in physical struggles with his left extremity, the right attempting to force the left to comply with some particular activity or to cease to act in a manner that the left hemisphere found objectionable or annoying. \[...\] In general, these findings indicate that the isolated right cerebral hemisphere of 2-C was able to understand and follow certain simple verbal commands, obtain and maintain knowledge \[...\], as well as respond, make decisions and act purposefully- even when his left hemisphere had no idea as to what information the right possessed and why it was behaving in a particular manner. **Given the differential behavioral observations with regard to the activity and responsiveness of the left half of their bodies, it appears that 2-C (unlike 1-C) is possessed of two minds, one of which resides within the right, the other within the left cerebral** hemisphere. Nevertheless, it appears that 2-C's left hemisphere remains predominant in regard to most expressive activities.

The bold text is probably what fueled the wiki article. To me, personally, the 'hatred' and frustration of C-2 is easily explained by the loss of body control. Who wouldn't feel frustration and resentment to that side of the body?

Indeed, a paper by Andrew & Akelaitis (1945) explains a similar behavior by their (partial-)split-brain patients with diagnostic dyspraxia. These authors explain the phenomenon not by a dualistic consciousness, but 'simply' by an **unbalanced inhibitory influence** of the dominant hemisphere over the non-dominant side. This decreased inhibitory control was hypothesized to lead to the uncoordinated behavior on the non-dominant side. These symptoms generally diminish over time, as the brain deploys alternative inter-hemispheric routing of communications. This sounds more plausible to me.

Lastly, there is a a publication that coins it "alien hand syndrome" (Feinberg *et al*., 1992). They too, ascribe the phenomenon by a disturbed inhibitory interhemispheric control, and I quote:

> Callosal AHS \[alien hand syndrome\] is best explained by hemispheric disconnection manifested during behaviors requiring dominant-hemisphere control.

So I conclude form this quick literature review that Joseph ascribes the presence of two minds based on something that can be explained at a more basic level, and hence by a more simple model, namely disinhibited motor control. Given the principle of parsimony, I conclude his observations were right, but that his conclusions were not.

<sub>**References**
**-** Andrew & Akelaitis (1945) *Am J Psychiatr*; **101**(5): 594-9
**-** Feinberg *et al*., *Neurology* (1992); **42**: 19-24
**-** Joseph, *J Clin Psychol* (1988); **44**(5): 770-9</sub>
> 4 votes

# Answer
Joseph's description of his patients fascinated me. The concept of two minds fighting for control isn't a new one to me, but was previously restricted to science fiction and/or horror genres. How strange to find a real-life example of it.

What I find unsatisfying about the explanation of "reduced inhibitory control of the dominant hemisphere over the non-dominant one" is this: Where did the alien hand's impulse to turn off the TV come from?

Consciousness and intent seem closely related. I suppose One consciousness can have multiple intents, but the act of picking up a remote and turning off a television is a fairly complex one; it implies a conception of the remote and the TV, and more importantly, a desire or will to turn it off.

It seems to be implied that the "dominant" hemisphere is in control of the mouth and perhaps by implication the verbal centers. Were that not the case, it might be difficult for the patient to communicate at all. Perhaps there are individual bodies for whom this is the case, but they're unable to tell us so!

Split personalities seem relevant--a brain that hasn't lost interconnectivity entirely, but which localized it's activity excessively--doesn't operate in parallel--"takes turns"--Isn't "integrated" or "cohesive." Just what came to mind.

Without being able to talk to the patient, or to Joseph, it's very hard to say whether Joseph's conclusions were correct. Is/was Joseph a smart guy? Is he prone to overly dramatic explanations, or would he only say something like this if he was quite sure it was true? I'll edit this when I get a chance to look at it in more detail.
> -1 votes

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Tags: neuroscience, consciousness
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title: Why do people want to have children?

text:
# Question
Title: Why do people want to have children?
Sooner or later most people will want to have children. What are some of the most common psychological reasons leading people to want to have children? What are their motivations and expectations?

# Answer
> 2 votes
There are many reasons why people want to have children :

* Some want to have children because they hope it can save their declining marriage / relationship
* Some want to have children because they feel instinctively driven towards it
* Some want to have children because they feel they're supposed to
* Some want to have children because they feel they're missing "something" in their lives
* Some want to have children because they want to learn more about themselves
* Some want to have children because they want to learn more about the man or woman they love
* ...

Still, I believe most reasons why people want to have children are perfectly captured by this single quote :

> Nevertheless, if you ask me, most people have children just as their own enthusiasm about life begins to wane. A child allows us to revisit the excitement we once felt about, well... everything. A generation later, our grandkids bump up our enthusiasm yet again. Reproducing is a kind of booster shot to keep us loving life.
>
> ― Chuck Palahniuk, *Damned*

---
Tags: social-psychology, developmental-psychology, cross-cultural-psychology
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# Question
Title: What if people understand or interpret words differently in their mind?
Let's think about it, we have all adopted to learn the meaning of words through experiences or emotions. We didn't learn each and every word from a dictionary. What if I understand a word slightly differently in my complex mind? Could it result in some sort of pessimistic or optimistic or abstract outcome? And how often is this case true in our society?

# Answer
> 4 votes
Quite certainly this is the case (even if you learn all words from a dictionary), but this is more of a philosophical debate. It is unclear what you are after when referring to 'pessimistic', 'optimistic', or 'abstract' outcomes, but I can point you in the right direction in case you want to read up more on this subject.

One concept that comes to mind from linguistics and philosophy of language is **indexicality**.

> ... an indexical behavior or utterance points to (or indicates) some state of affairs. For example, *I* refers to whoever is speaking; *now* refers to the time at which that word is uttered; and *here* refers to the place of utterance.

However, some argue the same holds true for almost any utterance. (Suchman, 1986)

> Among philosophers and linguists, the term *indexicality* typically is used to distinguish those classes of expressions whose meaning is conditional on the situation of their use in this way from those such as, for example, definite noun phrases whose meaning is claimed to be specifiable in objective, or context-independent terms. **But the *communicative* significance of a linguistic expression is always dependent on the circumstances of its use.** A formal statement not of what the language means in relation to any context, but of what the language-user means in relation to some particular context, requires a description of the context or situation of the utterance itself. And every utterance's situation comprises an indefinite range of possibly relevant features. Our practical solution to this theoretical problem is not to enumerate some subset of the relevant circumstances—we generally never mention our circumstances as such at all—but to "wave our hand" at the situation, as if we always included in our utterance an implicit ceteris paribus clause and closed with an implicit et cetera clause.

<sub> Suchman, L. (1986). Plans and situated actions. New York, Cambridge University. </sub>

# Answer
> 3 votes
Much of what we perceive cannot be expressed by language. It's unspeakable. As a consequence, differences in interpretation are very common, especially when it involves complex abstract concepts or highly subjective emotional experiences.

To quote **Kim Krizan**:

> Creation seems to come out of imperfection. It seems to come out of a striving and a frustration. And this is where I think language came from.
>
> I mean, it came from our desire to transcend our isolation and have some sort of connection with one another. And it had to be easy when it was just simple survival. Like, you know, "water." We came up with a sound for that. Or "Saber-toothed tiger right behind you." We came up with a sound for that.
>
> But when it gets really interesting, I think, is when we use that same system of symbols to communicate all the abstract and intangible things that we're experiencing. What is, like, frustration? Or what is anger or love?
>
> When I say "love," the sound comes out of my mouth and it hits the other person's ear, travels through this Byzantine conduit in their brain, you know, through their memories of love or lack of love, and they register what I'm saying and they say yes, they understand.
>
> But how do I know they understand? Because words are inert. They're just symbols. They're dead, you know? And so much of our experience is intangible. So much of what we perceive cannot be expressed. It's unspeakable.
>
> And yet, when we communicate with one another, and we feel that we've connected, and we think that we're understood, I think we have a feeling of almost spiritual communion. And that feeling might be transient, but I think it's what we live for.

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Tags: developmental-psychology, language
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# Question
Title: What is the information storage capacity of the human brain?
Related/bonus points: I seem to remember reading about some equation that states the amount of information that can be held by a neural network with n neurons in it arranged in l layers, or something vaguely like that (n and l probably weren't even the letters in it.) Can anyone help me remember what I'm thinking of?

(The brain is a very large neural network. So, if we have an equation for neural networks, we should be able to get an estimate of the information contained in the human brain's neural network.)

# Answer
**Disclaimer:** Quantifying the capacity of the human brain is quiet complex as you might imagine. And although in cognitive neuroscience we often compare the brain to computers this is not an exact comparison, in many ways the brain is far more complicated and encodes information in a very different way than the comparison of CPU processors and hard-drives. The short answer is that we have understandings about capacity under specific situations regarding STM, but LTM capacity is mostly based on estimates.

**TL;DR:**

**Estimates of the brain's information storage capacity vary from 10^13 to 10^18 bytes (10 terabytes - 1 exabyte), and even this range should probably be taken with a grain of salt.**

**Estimates of neural processing capacity range from 10^18 to to 10^25 FLOPS, and this range too might ought be taken with a grain of salt.**

The long version:

Memory in the brain is often split by cognitive psychologists into several different modules, such as the memory storage model suggested by atkinson and shiffrin; attention-\>short-term(STM)-\>long-term(LTM).

Fig 1.

**This model is largely inaccurate as the brain encodes information relative the type of information received**, for instance auditory inputs will be processed by neural areas associated with auditory processing first. In addition attentional processing, unlike in this model, relies heavy in precognitive processing e.g. if you are hungry you will attend more to food. That being said we still use STM and LTM to distinguish between memory that is in use and memory that is stored.

**Short-term memory capacity**

The rather brilliant researchers Baddley and Hitch developed what is perhaps the most compelling models for short-term memory processing. The working memory model (see Fig. 1) accounts for differences in information types and how it is held within the processing centres of the brain.

Fig 2.

A meta-analysis of 400 studies has displayed good support for the three main modules of cognitive memory. Generally speaking the central executive can be considered as the processor, while while the episodic buffer, phonological loop and visit-spatial sketchpad may be the modular RAM which holds information for processing.

According to Baddley the phonological loop can hold about 2 seconds of auditory information, this would be a list of unrelated words with a task designed to restrict rehearsal and encoding of information. However if the information was related, say "Our lecturer told us to read chapter 3 of working memory" we could hold more of the information as its related and may be chunked together. 'Chunking' is a feature of memory that complies similar information together. The capacity recorded generally depends on numerous factors, such as the task type, time between learning and recall, and the significance of the information. In addition we can also add age and context (internal and external) as factors influencing memory recall. Overall we can't identify the exact capacity of working memory due to the complexity of information processing, what we can say is that working memory deals with small amounts of information spit across different modules, and relates this to LTM. Although that small amount of information is probably a lot more than your average super computer can process as this post indicates.

**Long-term capacity**

As with STM, LTM is modular in anyways. However the total capacity is somewhat related too neurons, with 86-100 million neurons and 1000 glia cells thats means the human brain has a large capacity for storing information. However as previously mentioned these neurons relate to particular types of information. With regard to processing capacity the human brain is estimated to be \[10 to the power of 17\] 11 flops per sec, according to the blue brain project. Another recent estimate puts the processing capacity of the brain at 10^28 Flops.

Fig 3. A comparison of recent predictions of neural processing capacity and current fastest Super CPU

A different measure of calculating processing capacity has been devised by Grace and Christiano who stated the following...

> We can use Traversed Edges Per Second (TEPS) to measure a computer’s ability to communicate information internally. We can also estimate the human brain’s communication performance in terms of TEPS, and use this to meaningfully compare brains to computers. We estimate that the human brain performs around 0.18 – 6.4 * 1014 TEPS. This is within an order of magnitude more than existing supercomputers. TEPS = synapse-spikes/second in the brain

> = Number of synapses in the brain * Average spikes/second in synapses

> = Number of synapses in the brain * Average spikes/second in neurons

> = 1.8-3.2 x 10^14 * 0.1-2

> = 0.18 – 6.4 * 10^14

So the brain operates at around 18-640 trillion TEPS, while closest supercomputer is 2.3 * 10^13 TEPS (23 trillion TEPS).

Memory has been calculated to be around 2.5 petabytes (2.5 * 10^15 bytes), as reported here (seems to be based upon speculation by Prof P Reber). Another estimate has the neural memory capacity at 8∙10^19 bits--that's over 8 quintillion (10^18) bytes. Some researchers at Berkeley have suggested a relatively small 10-100 terabytes (10^13 to 10^14 bytes). All these estimates are based on variations in calculations relative to neuron density and and synapse connections across the whole brain. The larger estimates take addition account of other factors involved in neural communication. But the overall criticism I have is that we can't simply say that one synapse is 1 byte or 200 calculations per second.

The term estimate is generous here; guesstimate would be far more accurate. Individual neurons are complicated enough; moving to distributed and interconnected networks in the brain is just another level. Neurons do not conduct calculations independently; they rely heaving on context and information types. So we can say the processing of the brain is modular, in fact we already know this to be true to initial sensory processing. There is also no clearly obvious separation of memory from processing, although we know in motivation for instance certain areas will activate (the so called 'reward system') when assessing motivational objects. We won't say this is memory but it relies on it previous associations in memory. So some areas of the brain are used to assess rather than recall but they will activate together. The point being that we can't bundle all neurons together to calculate memory or processing. We just don't know what the vast amount of neurons are doing right now.

I highly recommend this report, for more information and references regarding computational and memory estimates.
> 14 votes

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Tags: cognitive-psychology, cognitive-neuroscience, memory, neural-network
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# Question
Title: What is the relation of visual quality and distance from the central field of view?
I have read somewhere that

> Our visual perception degrades non-linearly with distance from the fovea.

However, it was not referenced. I was wondering if there is a reference talking about this?

Also, is there a scientific reference stating the degradation of vision as a function of degrees in the field of view?

# Answer
Assuming you are talking about the ability of the visual system to resolve **spatial detail** (resolution, if you wish), then your question is on **visual acuity as a function of eccentricity on the retina** (Fig. 1).

Due to the densely packed cones at the fovea (corresponding to the central field of view (FOV), see Fig. 1), visual acuity (VA) is the greatest at the center of fixation. More eccentrically, VA declines markedly. *E.g.*, at 10 minutes of arc (1/6 of a degree) from fixation, there is a 25 % loss of visual acuity (Fig. 1.) This dependence of VA on eccentricity is indeed **nonlinear** (*cf*. Fig. 1) and correlates with the cone packing density and photopic resolution in the region up to a few degrees eccentricity.

However, at larger eccentricities, visual acuity is worse than that predicted by cone spacing alone, indicating that other post-receptoral retinal elements are the limiting factor. One of these factors is the **increased density of rods in eccentric regions**; rods are built for speed and **sensitivity**. The latter is accomplished in part by **funneling the inputs of multiple rods onto a single retinal ganglion cell (RGC)**. RGCs transmit the signals via the optic nerve to the visual centers in the brain stem, ultimately ending up in the brain. Foveal cones, on the other hand, are connected 1:1 and hence the spatial resolution and thus SA is much better in foveal regions. **The foveal region contains high densities of cones** (good VA), while more eccentrically more rods are present (worse VA); see Fig. 2. This is exactly the reason that we read by focusing our central foveal view on the characters.

Fig. 1. VA as a functin of eccentricity. Source: Kalloniatis & Luu (2016)

Fig. 2. Rod and cone densities as a function of eccentricity. Source: Kolb (2016)

**References**
**-** Kalloniatis & Luu. **Visual acuity**. In: *Webvision. The Organization of the Retina and Visual System*. Kolb *et al*. (eds). Utah University (2016)
**-** Kolb. **Photoreceptors**. In: *Webvision. The Organization of the Retina and Visual System*. Kolb *et al*. (eds). Utah University (2016)
> 2 votes

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Tags: neuroscience, vision, neurophysiology
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# Question
Title: Is there evidence of a mechanism for transmission of instinct?
DNA would seem to be the only candidate for propagating instinctual behavior, yet I find that not credible. DNA mainly codes for the production of protein structures (like enzymes) and is mainly about cellular mechanisms like respiration. It is said that we have 99% of our DNA in common with another primate (Chimpanzee? Do we behave much like them?) and that we have about 50% in common with plants (Carl Sagan said an Oak Tree) which would indicate that only cellular-level information is contained in DNA.

It is a mystery how tissues and systems arise, so it should be an even greater mystery how *behavior* could be somehow passed along in a mechanism for folding proteins. **Is there any model that definitely links instincts to DNA, such that if the DNA is altered, the instinctual behavior changes?** If not, are there any candidates for the actual mechanism of instinct transmission?

# Answer
http://www.theguardian.com/world/2007/dec/12/japan.justinmccurry Here they talk about scientist who shut down fear of cat in mice behavior. After genetic engineering the mouse isn't afraid of the cat smell. The conclusion of this study is that fear (at least in this case) is not learned through experience, but a consequence of genetic evolution. In the end, they even explain that mice are still afraid by the sound of the cat. So it's seems to be possible to modify a really precise reaction and not just a large class of behaviors.

Also, all the complex chemicals activities in our brain are coded by dna, so it's not surprising that our instincts are inherited. For the 99% of dna in common with Chimpanzee, I have to say that 1% is still a big number of genes, and can make a huge difference. Also they might be some part of the dna that are not used anymore in the 99% (they are just relics of evolution).

Actually I found information (one from Carl Sagan) saying that big parts (sometimes 80% or 97%) of our dna are unused. I'm not sure about those numbers thought, and one has to be careful because the sources don't seems to be always reliable to me. (The best might be non-coding dna on wikipedia)

**References**

Kobayakawa, K., Kobayakawa, R., Matsumoto, H., Oka, Y., Imai, T., Ikawa, M., ... & Mori, K. (2007). Innate versus learned odour processing in the mouse olfactory bulb. *Nature*, 450(7169), 503.
DOI: 10.1038/nature06281 PMID: 17989651 PDF: http://www.academia.edu/download/45075404/Innate\_versus\_learned\_odour\_processing\_i20160425-21574-dycs42.pdf
> 2 votes

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Tags: behavior, genetics, evolutionary-psychology
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# Question
Title: Why does autism sometimes impede the ability to produce speech?
My seventeen year old brother is severely autistic and unable to communicate. He can produce sounds, and imitate words, but he doesn't respond to words in a way that suggests he understands them. His imitations are always imperfect, and this is what interests me most. For example, he can sort of say the first twenty numbers ('ah', 'tih', 'ee', 'hoh', that sort of thing.) He sort of gets rhythm, but not intonation or pitch.

Of course, every child is different, but are there reasons why an autistic teen who can clearly hear words has never in 17 years learned to accurately reproduce them? Dad once speculated that it was auditory, that he can't hear the sounds properly, but I suspect that it's physiological. I'd like to hear thoughts from people who know what they're talking about.

# Answer
> 5 votes
Difficulties with language is not actually a symptom of autism. Autism Spectrum Disorder involves difficulties in social communication and interaction, as well as restricted and repetitive interests or behaviours (DSM-V, 2013). The term "social communication" is referring to difficulties in the social aspects of language and other communication, such as matching verbal and non-verbal behaviour, rather than difficulties in language.

The language difficulties as described in the question sound like they could be related to the age-equivalence of the individual, although of course physiological hearing difficulties can't be ruled out until it is assessed. All children progress through a sequence of language development (Tager-Flusberg et al., 2010):

1. Pre-Verbal

* Babbling, gestures
    * Typically developing children aged 6-12 months
2. First Words

* Non-imitated, spontaneous single words
    * Some of the speech is intelligible, and uses consonant sounds typical in babble
    * Typically developing children aged 12-18 months
3. Word Combinations

* 2 and 3 word combinations, including nouns, adjectives and verbs
    * Typically developing children aged 18-30 months
4. Sentences

* Children create sentences, now using plurals and prepositions
    * Typically developing children aged 30-28 months
5. Complex Language

* Language for a range of topics, using complex grammar, in different discourse contexts
    * Pre-school aged typially developing children

Tager-Flusberg et al. (2010) have a great table (Table 1) in their article outlining their proposed benchmarks for each of these phases. As the child progresses, their phonology (speech sounds) improves as well as their vocabulary, grammar, etc. Thus, your brother may be imitating the sounds he hears as best he can within his level of language development.

# Answer
> 2 votes
### What is Autism?

Psychologists, psychoanalysts and neuroscientists all commonly apply a triune model of the brain :

* The Reptilian complex (aka “instinct” aka “the Id”) : where primitive subconscious emotions (such as sadness, anger, fear and happiness) reside and which is correlated to primitive neurochemical algorithms that measure one’s capacity to take care of oneself.
* The Paleomammalian complex (aka “consciousness” aka “the Ego”) : where individual consciousness resides, and which is correlated to defensive, perceptual, intellectual-cognitive, and executive functions.
* The Neomammalian complex (aka “intuition” aka “the Super-ego”) : where collective consciousness resides, and which is highly correlated to the internalization of cultural rules, mainly taught by parents applying their guidance and influence.

In Autistic individuals, the Neomammalian complex does not behave as it normally should, which could have any of a multitude of causes. In essence, that means that Autistic people are lacking what is commonly refered to as a **“gut feeling”**. Autistic people can’t just follow “whatever their heart desires”. So they need to analyse whatever data they have all the time to compensate for that lack.

---

### Autism and emotions

The emotional life of Autistic people is no less intense than that of other people (if not more intense), but — due to the lack of a “gut feeling” — it is not as layered. Much of the wide range of subtle nuances in their emotional spectrum of “Neurotypicals” (aka “normal people”) is completely alien to Autistic people.

The Autistic emotional life is almost exclusively an expression of the level of (dis)comfort one experiences at any given time. While that may seem a very limited range of emotions, the emotional life of people with Autism can nevertheless be just as intense as (if nor more than) that of “Neurotypicals”.

Because Autistic people need to analyse everything all the time whenever “Neurotypicals” can just rely on their “gut feeling”, Autistic people are far more sensitive to a multitude of stress factors, but also far more capable of experiencing a state of Zen-like tranquility when stress factors are minimal.

This means that Autistic people and “Neurotypicals” experience a vastly different emotional spectrum, with different triggers, different sensitivities, different preferences, etc. The obvious consequence thereof is that Autistic people struggle to comprehend the emotional spectrum of “Neurotypicals”.

Perhaps less obvious is that it’s no different the other way around. It is not just difficult for Autistic people to understand and communicate with “Neurotypicals”, but also for “Neurotypicals” to understand and communicate with Autistic people, because their perception of themselves and the world around them is so vastly different.

---

### Implicit learning and language

Because the Neomammalian complex does not behave as it normally should, Autistic people don't just lack only “gut feeling”. They also lack a mechanism known as **“implicit learning”** (or their capacity for “implicit learning” is very limited). This is a mechanism that allows humans to learn through observation at a sub-conscious level.

Because Autistic people can't learn at the sub-conscious level, they need to learn pretty much everything at a conscious level. Learning something at a conscious level is a lot harder and requires a lot more intelligence than learning something at a sub-conscious level. Because one's native language is typically learnt implicitly, Autistic people therefore require more effort and intelligence to be able to learn their first (native) language than other people.

Communication difficulties between individuals with Autism and so-called "Neurotypicals" therefore exist at two levels. Not only do both have a different emotional spectrum, but they also learn to express their thoughts and emotions in different ways, further widening the gap between Autistic and "Neurotypical".

# Answer
> 1 votes
There are often motor control issues, the case study below exemplifies these and an approach to overcoming them with help from technology. As well as the below, there are many personal accounts such as those of Carly Fleischman and Tito Mukhopadhyay that describe the struggle to align output with inner thought.

Language is More than Speech: A Case Study Morton Ann Gernsbacher, Ph.D. Abstract: Some individuals face severe challenges with producing oral language (i.e., speech). In this article a case study of a child who experienced severe challenges with speech development is presented. Medical records, historical home videos, audio recordings, and photographs, in conjunction with an extensive journal maintained by the child’s mother provide the basis for this report, which profiles the child’s development from birth to age 8;0. This child’s development demonstrates the necessity of distinguishing between language—the mental representation of concepts and their relations—and speech—one means for communicating mental representations. Journal of Developmental and Learning Disorders, Vol.8, 81-98.

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Tags: language, linguistics, autism
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# Question
Title: Can LSD connect sensory regions in the brain?
**How is it possible that after using LSD you can hear sounds and see colors?**

I have my own experience with this phenomenon. When I´m lying totally relaxed in bed and suddenly a door is closed loudly, I see an explosion of colors. Are the two brain regions responsible for hearing and seeing, if you´re totally relaxed (for example just before falling asleep), somehow more connected with each other? Maybe the two regions are disconnected in a relaxed mode, but when a sudden sound (or maybe a flash of light in the other direction) occurs the neural network associated with hearing is suddenly "scared" and sends a "cry for help" to adjacent regions (resulting in a flash of light or in the other direction a sound, but I've never experienced this).

I edited because the new answer is always welcome, though the first answer is very clear about this " tpo-cic".

# Answer
The phenomenon you are referring to is called **synesthesia**, which can be defined as (Sinke *et al*., 2012):

> Synesthesia (Greek: *syn* = together; *aesthesis* = perception) is \[...\] a crossing of sensory perceptions, where stimulation within one sensory modality/stream leads to an internally generated perceptual experience of another sensory modality/stream.

Synesthesia does not have to be drug-induced; there are people that experience it always (synesthetes). Their perceptions are often quite subtle, for example, specific written characters assume specific colors (Sinke *et al*., 2012).

There are no explicit models for drug-induced synesthesia (Luke & Turhune, 2013). Nevertheless, the neurophysiological changes brought about by them can provide models for why hallucinogens can induce a synesthetic state.

The two major classes of **psychedelic hallucinogens**, the indoleamines (e.g., LSD) and the phenethylamines (e.g., mescaline), have a common site of action, namely **activation of serotine (5-HT) receptors**. Specifically, they are **partial agonists** of the **5-HT2A** and other 5-HT2 receptors in the central nervous system. The noradrenergic locus coeruleus and the cerebral cortex are among the regions where hallucinogens have prominent effects through their actions upon a 5-HT2A receptors.

In general, hallucinogens like LSD are thought to inhibit serotonergic neuron transduction, referred to as the **disinhibited feedback model**. Serotonin (5-HT) is mainly produced in the **raphne nuclei** (RN) of the midbrain. The RN extends its projections into the brainstem and up into the higher cortex. It has been suggested that neurons of the RN may inhibit sensation, thus protecting the brain from sensory overload. Thus, 5-HT may be labeled to be primarily an inhibitory neurotransmitter. A decrease in 5-HT activity hence leads to disinhibition of the next neuron in the chain (e.g., neurons in the cortex) and becomes more active (Sinke *et al*., 2012). This increased activity of the cortex may in turn explain the hallucinogenic activity of LSD and related drugs (Sinke *et al*., 2012).

However, a few 5-HT receptors are excitatory ion channels (5-HT3), and some 5-HT receptor subtypes may have excitatory effects (Sinke *et al*., 2012). Specifically, **5-HT2A receptor activation** has been shown to directly mediate an **enhancement** of nonsynchronous, late components of **glutamatergic excitatory postsynaptic potentials at apical dendrites of layer V cortical pyramidal cells**. Hallucinogens indeed increase cortical excitability and activate large areas of the cortex. It has been proposed that this effect of hallucinogens on cerebral glutamatergic transmission may in fact be responsible for the higher-level cognitive, perceptual, and affective distortions produced by these drugs (Aghajanian & Marek, 1999). Along the lines of these observations, the effect is quite similar to the disinhibited feedback model, in that the effects of drug intoxication are due to enhanced activation of brain regions. With regard to synesthetic effects, it is proposed that this abnormal activity **spreads to neighboring sensory areas that, in turn, lead to cross-modal sensory activations and hence synesthesia** (Sinke *et al*., 2012).

Since serotonergic systems appear to be intimately involved in the control of sensation, sleep, attention, and mood, it may be possible to explain the actions of LSD and other hallucinogens by their disinhibition of these critical systems (Sinke *et al*., 2012).

**References**
**-** Aghajanian & Marek, Neuropsychopharmacology (1999) **21**: 16S–23S
**-** Luke & Turhune. Frontiers in Psychology (2013); **4**: 753
**-** Sinke *et al*., Consciousness and Cognition (2012); **21**: 1419–34
> 7 votes

# Answer
**In a recent study**, brain scans revealed that people under the influence of LSD experience images through information drawn from many parts of their brains, and not just the visual cortex at the back of the head that normally processes visual information. While under influence, regions normally segregated spoke to one another. Further images showed that other brain regions that usually form a network became more separated.

Both alterations in your brain perfectly explain **the many differences in one's perception** while under the influence of LSD, which can include (but doesn't necessarilly include) **synesthesia**.
> 5 votes

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Tags: cognitive-psychology, neuroscience, cognitive-neuroscience, neurophysiology, psychopharmacology
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title: What is the ACT-R model of learning?

text:
# Question
Title: What is the ACT-R model of learning?
I am reading this paper titled: `Effect of Temporal Spacing between Advertising Exposures`

In this paper, the author mentions the ACT-R model and how it explains an optimal information- retrieval system in which items are stored in such a way that the cost of retrieval is minimal.

However, as I am not from a cognitive psychology background, I was unable to find the paper which proposed the model. (As the model is used and extended in many paper, I wasn't been able to find the original one).

**So, can anyone give a (dumbed down) explanation of how the ACT-R model works, and how it explains information storage?**

---

\[Update\] From the wikipedia link of ACT-R, I understand how the information is segregated. However, I still didn't understand how it is being stored and the learning process, and how it tries to minimize the cost of retrieval and (try to) maximize recall. (If it is already present in the wiki page, then the technical jargon might have confused me.)

# Answer
ACT-R can best be summarized with this (tiny but more recent) graph:

ACT-R is a cognitive architecture that tries to explain as much of human behavior as possible with as little rules as possible. It works at a high level of abstraction and came down to a list of so-called "modules", each having its own functions. The exact mechanisms of each of these modules are actually mathematical models which are based on many years of research. Each module has an accompanying buffer, which can be seen as an accompanying temporary storage unit which allows information to flow between modules.

One module is the visual module, in which vision and attention are modeled. When a stimulus is presented, the model will/may focus its attention on it. The time for it to do so is based on the location the model's attention was focused and the distance to the new location (Fitts's Law like).

Then, there is the manual module, which calculates how long a particular motor movement might take. Again, Fitts's law is a large part of this.

The more interesting modules are the Declarative Module and the Imaginal Module, and the Goal Buffer. In the declarative module factual information is stored. I also wrote something about it here. The paper I cited over there described how memories decay over time and how this decay may become slower (the effect of studying at intervals). This paper may especially be interesting also. Incorrect facts may also be stored but, since incorrect facts are encountered less often, they are are more easily forgotten.

The imaginal module is similar to working memory. Here you store information temporarily to allow short-term memorization. When a piece of information, also known as "chunk" is removed from this module, it automatically goes to the declarative module. There, depending on how often you use that "chunk", it will decay in a more or lesser degree. Placing something in the imaginal buffer is thus similar to mentally rehearsing.

The Goal buffer keeps track of what you are doing. For every little sub-task there is, you can set a goal. The goal-buffer is especially important for selecting the right production rule (see below).

## The core of ACT-R

All these modules come together in the Procedural module, in which production rules are stored. Production rules is analogous to procedural memory, which is the knowledge of how to execute a (part of) the task. It is here that all information comes together, and determines what the next step of action may be. In ACT-R, the procedural module is a BIG if-then-statement. If the goal is to do X (taking from the goal buffer), and we have knowledge y (from the retrieval buffer), and we see information z (from the visual buffer), then we can perform action A (via the manual buffer).

Sometimes, there are more production rules having the same conditionals. That means, if the goal is to do X (taking from the goal buffer), and we have knowledge Y (from the retrieval buffer), and we see information Z (from the visual buffer), then we can either perform action A or action B (via the manual buffer). This, the conditionals and corresponding action, are stored as two separate production rules. So we have Rule A and Rule B, which may be selected if we see X, Y and Z. Both production rule has a Utility value, i.e. a value of how successful the outcome was of that execution. The higher utility is, the bigger the probability of selecting it. This allows humans to make mistakes (selecting a wrong production rule) and to learn from these mistakes. Production rules that are successful will increase their Utility, whereas rules that are more often unsuccessful will have their utility decay over time.

## Example

One thing ACT-R has modeled is solving mathematical equations. For this, we need some assumptions. We are highly trained in additions from up to 50, so we can retrieve these facts without a problem. Then, we go into our production rule:

> IF
> Goal = addition
> Visual = 5+9
> THEN
> new Goal = retrieve
> Imaginal = 5+9 (to temporarily remember)

Now the next rule:

> IF Goal = retrieve
> Imaginal = 5+9 (here you use the temporarily remembered info)
> THEN
> Declarative = 14 (here, the result of the memory retrieval is saved)
> New Goal = Type answer

Then a final rule:

> IF
> Goal = Type answer
> Declarative = 14
> THEN
> Manual = Type 14. (here, a value is calculated of how long it would take to move your hand from Base position, to 1, to 4).

This is pretty much how ACT-R works. I bet that the IF-THEN syntax is not completely correct, but this is the essence. With basic IF-THEN rules, and knowledge and information from different modules, you can perform any task. Do note that ACT-R works at a very high level of abstraction (plus you can manually adapt the decay rate of memories to make the data fit better). Not every module is thus very well explained and there is quite some criticism on the model. However, the simplicity-explainability ratio (Occam's razor?) is very nice. For the best description of the model, I recommend the book "How does the human mind occur in the physical universe" by John Anderson.

## Examples of mistakes

For completeness I will also describe two mistakes that can occur. The first mistake is an incorrect memory retrieval. As a beginner in learning to count, you may have accidentally answered 13 once instead of 14 on the equation. This means it is saved in the declarative memory, but, most likely, activation has decayed a little. Because the retrieval process is stochastic and the activation value only serves as probabilities, it is possible that you accidentally select 13 instead of 14. Very simply, the second conditional will become the following.

> IF Goal = retrieve
> Imaginal = 5+9 (here you use the temporarily remembered info)
> THEN
> Declarative = 13
> New Goal = Type answer

The second way a mistake can be made is by selecting a wrong production rule with the same conditionals. For instance, during additions, you learn that 5+9 equals 14, and you see a pattern: you add a one and remove one from 5. because this is a successful strategy in some cases, it may actually gain some utility. So, as the innocent child that you are, when you see 15+9 you answer 114; you added a one and removed one from 5. This will be a production rule with the exact same conditionals, but where you perform a different action. The first production rule could then look like this:

> IF
> Goal = addition
> Visual = 5+9
> THEN
> new Goal = move One
> Imaginal = 5+9 (to temporarily remember)

After this, you would not follow the same steps anymore, because the goal buffer holds a different value ("move One" instead of "retrieve"). This means a different production rule will be selected.

## Tutorial

A tutorial of ACT-R exists which rather nicely takes you through the steps of basic model making, the exact syntax and the structure of the modules/buffers.
> 8 votes

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Tags: learning, cognitive-modeling, act-r
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# Question
Title: Why is it that in TV series the major part of the shots don´t last longer than 10 seconds?
While watching TV series (Game of thrones, Death in paradise, New tricks, etc.) I try to count how long one shot was shown before the next shot was shown. The duration of the shots almost never exceeded 10 seconds. Is there some psychological reason for that?

# Answer
> 2 votes
James E. Cutting has done a number of studies on this topic in the movie domain. Take a look at "Shot Durations, Shot Classes, and the Increased Pace of Popular Movies" (Cutting, 2015):

> "The pace of popular movies has increased and statements about this trend can be found in both the popular media and in scholarly works (see, for example, Bordwell and Thompson 2004; Bordwell, Staiger, and Thompson 1985; Cutting, Brunick, DeLong, Iricinschi, and Candan 2011b; Salt 2006, 2009)"
>
> "... shorter shot durations make for more cuts, which in turn make for
> more intensified demands on viewers’ attention."

More work can be found here: http://people.psych.cornell.edu/~jec7/pictures\_film.htm

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Tags: cognitive-psychology
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# Question
Title: Can normal brain activity arise from no (or random) brain activity?
I wonder how stable the brain is as a dynamical system. In other words, how important the state (current activation) of the brain is for its further functioning. Would the brain recover from a state of zero or random activity given sensible inputs from the environment, e.g. visual and auditory input?

By zero activity I mean equilibrium potential everywhere and no spikes. By random activity I mean independent random potentials and thus an initially random spike pattern.

Of course, normal brain activity is needed to keep people alive (e.g. control breathing) but maybe there were cases where machines ensured vital control for brain-dead subjects or computer simulations of neuronal brain models. An answer from either view would be interesting.

# Answer
> 6 votes
There is no such thing as "zero" activity in regards to brain circuits. Even when you record neurons from a brain slice in vitro, you have spontaneous network activity. There is a few studies that suggest that brain circuits are chaotic, where infinitesimal difference in the initial state will lead to exponentially diverging patterns of activity:

* Banerjee, A., Seriès, P., & Pouget, A. (2008). Dynamical constraints on using precise spike timing to compute in recurrent cortical networks. Neural Computation, 20(4), 974–993.
* London, M., Roth, A., Beeren, L., Häusser, M., & Latham, P. E. (2010). Sensitivity to perturbations in vivo implies high noise and suggests rate coding in cortex. Nature, 466(7302), 123–127.

To answer your question, the interaction between the internal state of a system and external stimuli is an important topic in neuroscience, and it is not clear how internally and externally generated dynamics interact. Here is a paper that discuss it under the term of "state-dependent computing":

* Buonomano, D. V., & Maass, W. (2009). State-dependent computations: spatiotemporal processing in cortical networks. Nature Reviews Neuroscience, 10(2), 113–125.

And there are multiple studies investigating spontaneous brain activity:

* Foster, B. L., He, B. J., Honey, C. J., Jerbi, K., Maier, A., & Saalmann, Y. B. (2016). Spontaneous Neural Dynamics and Multi-scale Network Organization. Frontiers in Systems Neuroscience, 10.

Hope it helps answer your question.

# Answer
> 4 votes
Based on computational models of resting brain activity, it can be assumed that the brain is a multistable dynamical systems that operates on the edge of a "critical" bifurcation point seperating a low firing spontaneous state (which can be seen as more or less random low firing activity) from a state of high frequency activity.

see for example the work from Deco et al. or Hansen et al.:

* Deco, G., & Jirsa, V. K. (2012). Ongoing cortical activity at rest: criticality, multistability, and ghost attractors. The Journal of Neuroscience : The Official Journal of the Society for Neuroscience, 32(10), 3366–75. doi:10.1523/JNEUROSCI.2523-11.2012
* Deco, G., Ponce-Alvarez, A., Mantini, D., Romani, G. L., Hagmann, P., & Corbetta, M. (2013). Resting-state functional connectivity emerges from structurally and dynamically shaped slow linear fluctuations. The Journal of Neuroscience : The Official Journal of the Society for Neuroscience, 33(27), 11239–52. doi:10.1523/JNEUROSCI.1091-13.2013
* Deco, G., Jirsa, V. K., & McIntosh, A. R. (2013). Resting brains never rest: computational insights into potential cognitive architectures. Trends in Neurosciences, 36(5), 268–74. doi:10.1016/j.tins.2013.03.001
* Hansen, E. C. a., Battaglia, D., Spiegler, A., Deco, G., & Jirsa, V. K. (2015). Functional connectivity dynamics: Modeling the switching
behavior of the resting state. NeuroImage, 105, 525–535.
doi:10.1016/j.neuroimage.2014.11.001

This state is the most economic state since it is on the edge of stability, which means that small inputs will lead to a bifurcation where the spontaneous state becomes unstable and the high firing "task-activated" state becomes stable. This provides high flexibility to brain operations. The control parameter in most of the models is the coupling strength between neurons. As Philippe mentioned, there is always some degree of spontaneous activity in normal functioning (healthy) brains, and I'm only aware of models which simulate neurons by means of chaotic systems or realistic neuronal spiking networks which have some low degree of connectivity/coupling to simulate a low firing "random" state, but there may be other models, which I do not know about.

But let's assume you simulate a model just with random spontaneous activity. Then there would be no information exchange between neurons when there is a low coupling, thus there would not emerge any form of resting state network, which can be seen as a form of "ghost attractors" where brain areas exchange information by spike synchronization.

So to answer your question, I'd say that the normal healthy brain is wired in a way that it can respond to environmental stimuli very flexibly and is able to switch from a resting state (for example when closing eyes and relax without any form of stimulation) to a task-activated or stimulus activated state very quickly.

But this can all be different when there is some form of physical damage to central hubs of brain function (think of the brain as small world network), which can't be compensated or substance induced changes like LSD or Psilocybin. Or think about mental disorder like schizophrenia or psychosis with visual and auditory hallucinations asf. There are probably many ways of altering the optimal operation point of the brain.

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Tags: neuroscience, cognitive-neuroscience, dynamic-systems
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# Question
Title: How long does it take to learn to cane travel?
How long does it take the average person (either sighted or blind) to learn to use the guide cane successfully for mobility purposes?

Source: Lions.

Because required training times will depend on many individual specific factors, such as willingness of the subject to undergo an arduous training program, age, possible additional disabilities, IQ/education etc., the best answer would be an **average training time** in a group of subjects that learned to use the cane **from scratch** (i.e., **naive** subjects at the start of the study). Ideally, it would be an answer expressed in **hours of training time**, because some measure expressed in weeks or months cannot easily be translated in how much time was actually spent on cane training. For example, the National Federation of the Blind (NFB) of extreme cases (very swift learners and non-learners), but anecdotal sample cases telling me that person *A* mastered it in a few weeks and person *B* not at all, isn't too helpful, unfortunately (I would like to refer to numbers in a manuscript I am preparing).

Ideally, the source should be a scientific publication, or obtained from a credible source, such as the NFB. I have been searching quite a bit, but without success.

# Answer
> 4 votes
**Short answer**
Generally, a few months of active, guided training.

**Background**
Based on an article from a guide cane instructor who is a cane traveler himself, I can answer the question as follows:

First off - it depends on at least three important variables;

1. The student's **background**;
2. The student's **aptitude**;
3. the amount of **time available** to the student.

Ad. 1 : If the student is planning only to use the cane in already familiar environments, the process will be easier. Fear of traffic, or unfamiliarity with it may complicate the learning process.

Ad. 2. The level of independence is important; an older persom who has been used to be guided by another, sighted person for years will have a hard time replacing those two eyes with a cane. A youngster, on the other hand, will likely be able to learn faster, be more motivated and more daring than an old person. The elderly may be less mobile and possibly afraid of falling, have balance disorders *etc*.

Ad. 3. Time should be measured in two ways: the number of hours per day and week, and the number of months to be filled with this schedule. The author of the cited article below started as a student spending **fifteen to twenty hours a week in guided practice** and that worked well for her. The author says to have known people who made good progress with **four to five hours of guided practice in a week**, **anything under three hours per week is probably getting rather thin**; and these hourse refer to **specific skill practice**, besides using the cane wherever and whenever possible.

The author spent **an intensive six weeks** on travel to reach a satisfactory level of skill. Most people he knows who worked steadily for **several hours a week**, plus **out-of-class everyday use** were able to gain sufficient skill to cane travel in **two to three months when starting as a beginner**.

**Reference**
**-** Bickford, *Future Reflections* (Winter 1996); **15**(1)

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Tags: learning, vision, sensation, perceptual-learning
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# Question
Title: Personality Models: The Big Five, the Seven Deadly Sins, and?
In Christian tradition, there are said to be "seven deadly sins": Lust, Gluttony, Greed, Sloth, Wrath, Envy, and Pride.

In Catholicism specifically, there are sometimes said to be seven virtues, each sin having an opposite: Chastity, Temperance, Charity, Diligence, Patience, Kindness, and Humility.

In a sense, this is a personality model. (Each sin/virtue duality can be thought of as a spectrum, with the sin lying at one end, and the virtue at the other. In the middle would be the "average" soul.)

In psychology, the "Big Five" traits come to mind, with the acronym "OCEAN": Openness to Experience, Conscientiousness, Extraversion, Agreeableness, and Neuroticism.

What other major personality models are out there that use 3-9 axes (plural of axis) to describe an individual's personality?

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Related questions that floated about:

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**Other clues (quotes and links:)**

Big Five Wiki on the context of the Big Five:

> The Big five personality traits was the model to comprehend the relationship between personality and academic behaviors.
> \[...\]

Tao Te Ching, Chapter 15:

> Hesitant, like crossing a wintry river
> Cautious, like fearing four neighbors
> Solemn, like a guest
> Loose, like ice about to melt
> Genuine, like plain wood
> Open, like a valley
> Opaque, like muddy water

Wikipedia Article: "Facet" (Psychology), a concept within the Big Five personality model

Wikipedia Article: Six Values in Positive Psychology:

1. Wisdom and Knowledge
2. Courage
3. Humanity
4. Justice
5. Temperance
6. Transcendence

Neurotransmitter/Receptor types/systems:

* Dopamine
* Serotonin
* Cannabinoid
* GABA
* Adrenergic (Epinephrine/Norepinephrine)
* Nicotinic
* ???

# Answer
Depending on your definition of 'personality model' there are plenty to choose from.

I don't have any good overview of similarities and differences, which are tests more than models, or which are really two names on the same model.

* Big 5/5 factor model. 5x6 axes. Tests include NEO-PI, MMPI-2, IPIP ++.
* Global 5. 5 axes
* BELBIN
* Emneagram/RHETI
* Hexaco
* Holland COdes/RIASEC
* Jung/MBTI/Kiersey/DISC, 16 PF, MENTI. 4 axes
* MOTIV
* R-Drive
* Temperaments. 4 axes
* Hartman. 4 axes
* Kolb/Mumford
* Learning styles, GrashaRiechmann styles, Dunn and Dunn styles, Canfield styles

Which ones you should focus on depends on what you are looking for.

Big 5\NEO-PI-R is the most scientifically supported model, so I mostly keep to that one. The hard part about Big 5 is the number of traits total (30), which takes a while to really learn, understand and remember. MBTI is useful in learning theory about personality types, differences and traits, but it lacks scientific support. The others I haven't studied much yet.

In general I think it's a good idea to use Big 5 as the base, and search for correlations with traits from Big 5.

Sources:

http://similarminds.com/personality\_types.html http://tcc.kcc.hawaii.edu/previous/TCC%202005/santo.pdf http://www.personalityresearch.org/bigfive.html http://hexaco.org/scaledescriptions
> 4 votes

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Tags: personality
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# Question
Title: How to help relieve test-anxiety in others
I teach, as a layman, young adult students who mostly try to get a degree part-time whilst juggling full-time jobs and small crumbs of left-overs of a private life.

As it is hard for them to do rock-solid preparation, there is often a serious amount of test-anxiety close to the exams and up to the point where they forget something they definitely had down before. I want to educate myself on techniques to relieve test-anxiety in others as a teacher. Google gives innumerable hits for relieving that form of stress yourself, but not from the educator's viewpoint. Any help would be appreciated.

# Answer
Being a layman, you can only give advice to the students. When their test anxiety is serious, the best advice you can give them is - ***seek professional help***.

There are, as you say, numerous ways to relieve 'normal' anxiety. A good web source is WebMD, that gives the following tips, which may aid your students too:

* Learn your students to study efficiently; your institution may offer dedicated **study-skill courses** to the students;
* You can learn them **test-taking strategies**;
* Students feel more relaxed if they study systematically and **practice the material** that will be on a test. Establish a consistent pretest routine. That way they'll learn what works best for them, which eases stress levels;
* Teach them **relaxation techniques**. There are a multitude of them, applicable to either right before the test, or during the test to help them stay calm, *e.g.*, breathing techniques, muscle relaxing strategies, closing the eyes and imagining a positive outcome, or meditation techniques;
* Remind them to **eat and drink**. Their brain needs fuel to function. They should eat a meal before the test and drink plenty of water. However, sugary drinks such as soda pops can cause the blood sugar to peak and then steeply drop. Also, caffeine may not be wise as it can increase anxiety;
* Let them **exercise**. Regular aerobic exercise, and exercising on exam day, can release tension;
* Urge them to get plenty of **sleep**. Sleep is directly related to academic performance. Preteens and teenagers especially need to get regular, solid sleep;
* Make sure your students can openly **discuss anxiety** issues with you;
* A student may have a **learning disability** that requires **professional help**. Test anxiety may improve by addressing the underlying condition that interferes with the ability to learn, focus or concentrate — for example, attention-deficit/hyperactivity disorder (ADHD) or dyslexia. If a student has been diagnosed with a learning disability you can provide them with assistance with test taking, such as extra time to complete a test or having questions read aloud;
* And again - urge them to seek **professional help**, if necessary. Talk therapy (psychotherapy) with a psychologist or other mental health provider can help them to work through their feelings, thoughts and behaviors that may cause or worsen anxiety. You can ask around at your institution if it has a counseling service in-house, otherwise you can advise your students to seek professional help outside the school's setting.
> 2 votes

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Tags: educational-psychology, anxiety
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# Question
Title: Categorization studies with a procedure similar to Shepard et al (1961) and Medin & Schaffer (1978)
I am looking for *performance* results from **categorization** studies with discrete stimulus features and reinforcement feedback. I need something like this:

```
stimulus  - correct response - performance after X trials
(1,1,1,0) -         0        -   20.1% correct
(1,1,0,1) -         1        -   23.3% correct
(1,0,0,0) -         1        -   82.0% correct
...

```

(e.g. Shepard, Hovland & Jenkins, 1961; Medin & Schaffer, 1978)

<sub> Medin, D. L., & Schaffer, M. M. (1978). Context theory of classification learning. Psychological Review; Psychological Review, 85(3), 207.
Shepard, R. N., Hovland, C. I., & Jenkins, H. M. (1961). Learning and memorization of classifications. Psychological Monographs: General and Applied, 75(13), 1-42. </sub>

# Answer
> 5 votes
You've described a very general type of study design which has probably been employed in hundreds of studies or more. Your question might profit from a more specific description of the type of study you're looking for.

A few examples that fit the bill just off the top of my head are:

Goldstone (1996) Isolated and interrelated concepts

Zaki and Homa (1999) Concepts and transformational knowledge

Kornell and Bjork (2008) Learning concepts and categories: is spacing the "enemy of induction"?

# Answer
> 3 votes
Of course, the type of data you use depends lot on what your model purports to explain. The way i take your question, you are looking for straight up artificial classification learning experiments. Is this correct?

If so, John Kruschke has published several of his most important datasets on his website. I have often used these in my model testing. His '93 and '96 papers in connection science are especially notable.

Unfortunately, Nosofsky has not done the same thing, but you can find PDFs on his website, many of which contain reports of data (i.e., tables) detailed enough to simulate. I'd especially look at his '86 paper in JEP General, but there is tons on his publications page and that's just the start...

Finally, one of my favorite, under-simulated, datasets was published in the '92 cogsci proceedings by Aha & Goldstone. PDF here

# Answer
> 2 votes
Bob Rehder's work may be of interest, for instance:

Rehder, B., & Hoffman, A. B. (2005). Thirty-something categorization results explained: Selective attention, eyetracking, and models of category learning. Journal of Experimental Psychology: Learning, Memory, and Cognition, 31, 811-829.

You will see some eye-tracking data on some classic results, but if you are after the so called *performance* aspects of the data, this will be reported also.

You might also find the following data interesting, they are working with discrete category dimensions and corrective feedback:

Blair, Mark R., et al. "Extremely selective attention: Eye-tracking studies of the dynamic allocation of attention to stimulus features in categorization." Journal of Experimental Psychology: Learning, Memory, and Cognition 35.5 (2009): 1196.

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Tags: cognitive-psychology, memory, learning, experimental-psychology, data
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# Question
Title: Is there a neural network model of Pavlovian Learning?
I am trying to find a computer simulation of Pavlovian learning. i.e. an action such as salivation in response to a stimulus such as a bell ringing.

Most neural network models I've seen seem to be more about trying to recognise things such as handwriting or speech rather than the stimulus-response model. And they don't usually incorporate the temporal nature of Pavlovian learning. e.g. Ring a bell, wait a bit, give dog food.

Are there any computer simulations of this? (Do they have a name?) Is there a connected neuron model of this?

# Answer
> 7 votes
In general, what you're looking for is a biologically plausible model of reinforcement learning and/or conditioning. I know of two publications in particular that address this.

The first is A Biologically Plausible Spiking Neuron Model of Fear Conditioning and the second is A Spiking Neural Integrator Model of the Adaptive Control of Action by the Medial Prefrontal Cortex. They both using the Neural Engineering Framework and a learning rule to modify the connection weights between ensembles of biologically plausible spiking neurons. These connections are modified to create and destroy associations between stimuli and an action. However, in the second paper, it's shown that the mechanism can also learn timing information.

# Answer
> 4 votes
I would classify pavlovian learning as a type of hebbian learning. Where events that occur together positively reinforce each other (different from reinforcement learning).

This idea has been modified into hopfield networks, and then their descendants boltzmann and restricted boltzmann machines. They use an algorithm called contrastive divergence which is effectively hebbian learning. It tries to make events that occur together produce more stable states, and events that do not occur together are made less stable, thus given a partial state, the network will be attracted to the stable state.

So if a bell rings, and food is received the net will learn that this is a (more) stable state and when/if only the bell rings then the net will naturally be attracted to the state, bell + food, as all other states are less stable.

(Unfortunately I do not understand contrastive divergence particularly well, it may be better to look it up yourself).

This work leads into unsupervised learning, deep learning and auto-encoders.

Although, on second thoughts, I should clarify that this doesn't currently work with temporal difference. So I don't know if I really answered the question.

# Answer
> 2 votes
A true classic -- the Configural-Cue model -- uses the Rescorla-Wagner rule to learn associations between cues and outcomes. Link1 Link2 Link3

In my view this is one of the most straightforward (i.e., simplest) models of conditioning, likely a good starting point for you.

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Tags: cognitive-neuroscience, theoretical-neuroscience, cognitive-modeling, neural-network
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