# Question
Title: Interclick interval resolution of the ear
Let's say I have an almost perfect metronome which ticks at 60 beats per minute, except for one beat that is slightly off from time to time. What's the maximum error this metronome can have without a human being able to notice the rhythmic default? Is there any study related to that? Also, would it depend on the metronome speed?

# Answer
> 3 votes
There have been studies on this, both with paired clicks and long streams of clicks. Normal listeners can detect changes of the sort you describe with essentially perfect reliability down to about 45 ms and with better chance performance below 30 ms. I haven't been able to find a study measuring the minimal threshold for this change, but from the studies I have found it should probably be in the 10-20 ms range.

As for how the interval affects it, the answer depends on the direction of change and the direction of interval change, so it is hard to give a single answer. The affect seems to be larger at larger interval changes.

Note that this is a very low-level task, with slightly higher modulation rates processed at the very lowest levels of the auditory pathway. It is also a task that is highly "conserved" evolutionarily, that is it is very consistent across species. Fish have similar performance to humans at this task. And not that in the stream study, it used mismatch negativity, which is a change in electrical activity in your brain that occurs even if you are not paying attention to the stimulus and don't consciously notice the change.

# Answer
> 2 votes
From mental chronometry studies, I would venture that 160 - 190 ms would be a reasonable lower limit for the deviation of a beat for a trained subject( i.e the time it takes to process the stimulus), the upper limit is somehow harder to estimate...

> What's the maximum error this metronome can have without a human being able to notice the rhythmic default?

Depends in general, the ability to discriminate a deviant beat in a set I believe is a learned behavior, so it could vary from individual to individual and training. Beat matching comes to mind, it takes a DJ anywhere from months to years to accurately tell by how much 2 songs beats are out of sync and to match them.

> would it depend on the metronome speed?

By speeding the metronome you are reducing the time in between ticks, so you are effectively making it harder to detect the deviation, (this also implies you are increasing the bpms).

---
Tags: hearing
---


# Question
Title: Does computer usage (YouTube, Facebook, etc. ) influence social abilities?
With computers, tablets and smartphones, people spend more and more time in front of a screen, and perhaps, less time with actual people.

In my experience, after spending a lot of time on my computer, I notice I am less able to hold a good conversation, sometimes lose a little bit of self confidence and care more about what others think.

Is there any scientific research that shows a relationship between social skills and computer usage (especially watching YouTube-Videos)?

# Answer
> 5 votes
Social media usage is still quite new and there have been no major longitudinal study that I know of, that has looked into how usage influences social abilities in the long run. If you limit it to youtube only, then I don't know of any study at all that looked at youtube usage only and social skills.

One of the reasons it's difficult to study this, is that people who are drawn to these online activities are not the same as others, and not everyone who uses them becomes "addicted" to them. In other words, we don't start with people having the exact same social or cognitive skills. In addition, people don't actually use them the exact same way (length of time, content, etc). Not to mention that people often don't just use one particular thing like youtube but many different sites and so that's another reason it's difficult to make comparisons.

Of course, there are ways to use them that can be of benefit. For instance, concerning younger people who use social media including youtube, The American Academic of Pediatrics mentions potential benefits, such as communicating and socializing, better learning opportunities, and access to health info, while warning of dangers such as cyberbullying, sexting, violation of privacy, powerful influence of advertisement, and last but not least, "facebook depression."

An interesting area of study is "internet addiction". The final decision was made not to include it in the latest psychiatric diagnostic manual (DSM-V), partly because as one article asks "Problematic Internet use: a distinct disorder, a manifestation of an underlying psychopathology, or a troublesome behaviour? Other authors however have a specific definition in mind, such as this editorial that states the four defining criteria of internet addiction:

> 1) excessive use, often associated with a loss of sense of time or a neglect of basic drives, 2) withdrawal, including feelings of anger, tension, and/or depression when the computer is inaccessible, 3) tolerance, including the need for better computer equipment, more software, or more hours of use, and 4) negative repercussions, including arguments, lying, poor achievement, social isolation, and fatigue.

**In summary**: There is a lack of good longitudinal research in this very important area. There is also problem with defining what is appropriate usage and what is not. But it is speculated that proper usage (e.g. access to useful info, or socializing) can be beneficial while inappropriate usage (e.g. online bullying) can be detrimental to mental health. Regardless of purpose of usage, excessive usage to the point of ignoring more important daily functions may also be a sign of mental illness, be it caused by the computer usage itself or as manifestation of another already present illness.

Hope this has been useful to you.

*References:*

*Block J. J. (2008). Issues for DSM-V: Internet Addiction. American Journal of Psychiatry; 165, 306–307.*

*O’Keeffe, G., & Clarke-Pearson, K. (2011). Clinical report the impact of social media on children, adolescents, and families. Pediatrics, 127, 800–804.*

*Starcevic, V. (2010). Problematic internet use: A distinct disorder, a manifestation of an underlying psychopathology, or a troublesome behaviour? World Psychiatry, 9, 92.*

---
Tags: social-psychology, internet, social-networks
---


# Question
Title: LAURA/LORETA source localization in Matlab
Is there a Matlab toolbox for doing source localization using LAURA or sLORETA within Matlab (not requiring additional software like LORETA-KEY, etc.)?

# Answer
The open-source Matlab package called Fieldtrip has a source analysis function in which you can specify the method you want. These include both sLORETA and eLORETA.

In case you did acquire LOERTA-KEY, you also import sLORETA files into Fieldtrip and continue further analyses.
> 1 votes

---
Tags: cognitive-neuroscience, eeg, neuroimaging
---


title: What self-image do most people have?

text:
# Question
Title: What self-image do most people have?
There seem to be a lot of studies about the influence of self-image on our psychology, but I've been wondering: Is there research on what type of self-image (positive, negative) most people have? Do people in Western countries tend to have a positive or a negative self-image?

# Answer
> 3 votes
Short answer:

> ... on the balance, most people tend to view themselves positively.

Longer answer:

Not much is clear about self-image. One thing that is clear is that self-image is not one thing. In the research literature, it can refer to a conglomerate of fairly independent / mildly correlated constructs, such as body image, self-schema, self-valuation, self-esteem, self-perceived physical attractiveness, self-worth, etc... That is to say, one can score positively on some of these measures and negatively on others, with little relationship between the scores.

Culture may indeed play a role as well:

> More recent research investigating self-esteem in other countries suggests that illusory superiority depends on culture. Some studies indicate that East Asians tend to underestimate their own abilities in order to improve themselves and get along with others.

The uncertainty between positive and negative self-image is underscored by the existence of both an above-average-effect, and a worse-than-average effect. Each may refer to different aspects of self-image, but may even refer to the same aspects!

> For example, while college students rate themselves as more likely than average to live to 70, they believe they are less likely than average to live to 100. People regard themselves as above average on easy tasks such as riding a bicycle but below average on difficult tasks like riding a unicycle.

---
Tags: cognitive-psychology, self
---


# Question
Title: Does homosexuality correlate with narcissism or finding yourself attractive?
I'm a heterosexual male. Male bodies do not appeal to me much. I find my own (average) body mediocre. At the same time I find average female bodies rather interesting and attractive. The same goes for faces and "male" and "female" character traits. So I wonder how homosexuals judge themselves.

Since gay men and lesbian women are attracted to bodies, faces and possibly personalities of the same sex, maybe they find their own bodies, faces and personality more aggreeable on average than the heterosexual, for whom persons of their own kind must by definition lack at least some aspects of attractiveness (i.e. the sexual and erotic appeal).

If this is so, then maybe traits like narcissism are more frequent and disorders like body dysmophic disorder are less frequent among homosexuals. In general terms:

**Do homosexuals like themselves more than heterosexuals?**

where "liking" includes anything from feeling attractive to disorders such as narcissism.

Or doesn't sexual orientation moderate "self-love" at all?

# Answer
What you have here is a hypothesis and it's almost impossible to answer this conclusively because you can't design a randomized study but only look at correlations. In addition, "narcissism" itself is far from a simple concept and used differently by different researchers. For instance some see is as synonymous with self-esteem and self-confidence, some don't.

In fact, your view is closer to some of the psychoanalytical views of homosexuality. For instance, a hundred years ago, in talking about narcissism and abnormal development, Freud suggested that people who had experienced problems during libidnal development (libido is a kind of instinctual sexual energy behind our psychological development), including gays and "perverts", instead of choosing their mother as their "love-object", they'd use themselves as the love object. He labeled this abnormal sexual development a kind of narcissism. The theory is more complex than that but I just wanted to give you an idea of the kind of views I was referring to.

Contemporary research does not follow this line of thinking nor talks about development, gays or not, in those terms. In fact many (not all) psychoanalytical concepts are no longer seen as scientific (=falsifiable) so they're not seriously studied these days in universities. You would instead find researchers look, for instance, at homosexuality and mental health (with a lot of attention paid to social factors; see Herek & Garnets, 2007), but not studies of narcissistic development in homosexuals, except a couple here and there in psychoanalytical journals.

I took a look and most recent study I found in a non-psychoanalytical journal was by an Israeli researcher, Rubinstein, published in 2010. In her study she found exactly what she believed based on Freudian conception, that gays were more narcissistic but had less self confidence than heterosexuals.

As the invited commentary on that study (Hartmann, same issue, can't find citing info) mentions, given that there is still stigma against homosexuals, one need a higher standard for offering the conclusion that she had (the study used only 200 Jewish students in their 20s living in Israel and within what Hartmann calls "forceful social and religious traditions", and had relied on self-report, which is far from objective). In her defense, Rubinstein did talk about three potential interpretations and also the limitations of her study.

**Summary:**

Some psychoanalysts believe that homosexuals are more narcissistic than heterosexuals but no good data is available to confirm that, partly because researchers try to be careful when they study sexual orientation because of potential misuse of findings, but more importantly because those conceptions of homosexuality are no longer seen as scientific or more useful/productive than current biological or psychological theories of homosexual development.

I hope you found this answer helpful.

**Works Cited**

*Freud, S. (1957). On narcissism: An introduction. In J. Strachey (Ed. and Trans.),The standard edition of the complete psychological works of Sigmund Freud (Vol. 14, pp. 67–104). London: Hogarth Press (Original work published 1914).*

*Herek, G. M., & Garnets, L. D. (2007). Sexual orientation and mental health. Annual Review of Clinical Psychology, 3, 353–375.*

*Rubinstein, G. (2010). Narcissism and Self-Esteem Among Homosexual and Heterosexual Male Students. Journal of Sex & Marital Therapy, 36:24–34.*
> 4 votes

---
Tags: physical-attraction, self, attraction
---


# Question
Title: IQ scores - fixed raw scores vs infinite tails of the underlying normal distribution of standard scores
When taking an IQ test, if a subject responds to all questions correctly, they will achieve the maximum (raw) score, a finite number. Yet, due to the test's normalisation that takes the median raw score across the population and defines it into a standardised score of 100, IQ scores are expressed not as raw scores but as standardised scores, or equivalently, a number of standard deviations (SDs) away from 100.

My question is: what sense does it make to speak of very high IQ scores, such as for instance 170, that correspond to an extreme in the distribution's tail, when, if one were to convert back to raw scores, this would seem to result in a raw score higher than the one corresponding to an "all answers correct" result.

Put more simply, my question is: since there is a hard-limit on raw scores, why is it that the normal distribution used to describe an IQ score can (theoretically) lead, along its tails, to infinitely-large numbers - as well as, conversely, to negative numbers - as raw scores, both extremes being out of the raw-scores range?

# Answer
The answer is provided by the Test theory, which distinguishes between the true value of a latent (=unobservable) psychological construct, in this case the IQ of a person, and the IQ score measured with an IQ test. A good test is objective, reliable and valid which ultimately means that each measured score reflects the underlying construct (measured IQ= true IQ). High validity means that the test measures what it claims to measure. If a person has an IQ 170 but the IQ test assigns that person IQ 160, because this is the highest possible score in that test, then this result is invalid and the test is not a good tool for measuring high IQ.

In practice, the test manual should clarify what is the IQ range, in which the test provides reliable and valid estimates of person's IQ. Furthermore, the authors may provide multiple test versions which differ in difficulty. For instance, Raven's Progressive Matrices come in three test versions: test for normal adults, test for children and mentally impaired individuals, and a test for people with above-average IQ. As you can imagine, the last-mentioned test features higher number of tasks than the normal version.
> 2 votes

---
Tags: statistics, iq
---


title: How many memory systems do we have?

text:
# Question
Title: How many memory systems do we have?
I read that humans have 2 memory systems.

One is fight or flight memory located in amygdala. Another is episodic memory located in hippocamus.

Then I've heard that there is another memory system. Semantic memory located on the temporal lobe.

So, how many memory systems do we have?

If I can derive most math formula on top of my head but keep forgetting where I put my glasses, is something wrong in my hippocampus?

# Answer
> 3 votes
> Okay, how many memory do we have?

Like many things in neuroscience & cognitive science, it depends on how you categorize it, it is also an evolving field and you might be surprised to know that the number of memory systems is closer to 10-12, although the number might go up or down in the future.

In general there are 2 ways of dividing memory: by time range ( Long term and short term) and by intentional recollection, each one further subdivides and overlaps at some points.

> One is fight or flight memory located in amygdala.

The Amygdala is a complex mass of gray matter that plays an important role in emotions, it both integrates and has a role in associative learning in between stimuli and experiences/feelings among other functions, so in a way it is involved in memory, ( emotional memory).

The fight or flight response on the other hand is a whole other complex subsystem of our bodies mainly involving the visceral motor system (the sympathetic division)

> Another is episodic memory located in hippocamus

Episodic memory is one of the subdivisions of memory, mainly dealing with events as opposed to facts ( that would be semantic)

The hippocampus is a crucial component to memory, but is part of a bigger system mainly involved with transfering and facilitiating the creation of short term memories to long term memories.

> If I can derive most math formula on top of my head but keep forgetting where I put my glasses, is something wrong in my hippocampus?

Most likely not, as this very brief and incomplete review hopefully shows you, there are a number of different systems at play for what we normally bunch up into the word memory, there are also different types of memories.

Deriving a math formula on the top of you head involves another type of memory, working memory, along with the phonological loop if you think in words about your equations ( these 2 are sort of buffers) , and long term memories across your neocortex with a number of connections and interconnections, in other words your whole brain lights up.

Forgetting your glasses on the other hand is usually a problem of not encoding the initial percept in the first place ( i.e. to increase the odds of you finding your glasses again, you need to consciously aknowledge where you are leaving them in the first place rather than just dropping them).

Additionally, what you do in between leaving your glasses and trying to recover them also influences how much you remember them.

As mentioned memory is a complex and deep subject, as way of sources here are a few books I consulted:

*\- Cognitive Neuroscience (Third edition) \- Neuroscience (Third edition)<br>\- In search of memory \- The seven sins of memory*

---
Tags: brain
---


# Question
Title: Why is amygdala located on paleo mamalian part of the brain?
We got 3 brains right. Reptilian. Mamalian. And the neo cortex thingy that makes us primate. And humans supposedly have tons of neo cortex and that what makes us human allowing us to code and code.

That means, things that reptilian have should be in reptilian brain.

Yet amygdala is located not on brain stem or reptilian brain, but in middle brain.

How come?

# Answer
The reason why the amygdalae are in the middle of the brain is because they are not part of the reptilian brain. The amygdalae interact with many areas of the brain and are in the limbic system. They are often referred to being the "fear centre", but they have roles beyond just being a simple threat detector.

Studies have found the amygdalae to be active not just during fear conditioning, but also when learning to link a previously neutral stimulus with a positive experience by

* interacting with reward areas of the brain like the ventral striatum, which **is** in the reptilian brain
* playing an important role in forming memories associated with drug use.
* being an important region for the consolidation of memories that have any strong emotional component - whether positive or negative.

the amygdalae (Source: Wikipedia)

There are functional differences between the right and left amygdala. In one study, electrical stimulations of the right amygdala induced negative emotions, especially fear and sadness. In contrast, stimulation of the left amygdala was able to induce either pleasant (happiness) or unpleasant (fear, anxiety, sadness) emotions.

For the idea of 3 parts to the brain, this idea was started by American physician and neuroscientist Paul D. MacLean. He originally formulated the triune brain model in the 1960s and propounded it at length in his 1990 book *The Triune Brain in Evolution*.

The triune brain consists of the reptilian complex (also known as the "reptilian brain"), the paleomammalian complex (limbic system), and the neomammalian complex (neocortex).

The reptilian complex, was the name MacLean gave to the basal ganglia which consists of the dorsal striatum (caudate nucleus and putamen), ventral striatum (nucleus accumbens and olfactory tubercle), globus pallidus, ventral pallidum, substantia nigra, and subthalamic nucleus.

basal ganglia (source: Wikipedia)

The neomammalian complex (neocortex) is a part of the mammalian brain. The neocortex consists of the grey matter, or neuronal cell bodies and unmyelinated fibers, surrounding the deeper white matter (myelinated axons) in the cerebrum.

neocortex - Human brain right dissected lateral view, showing grey matter (the darker outer parts), and white matter (the inner and prominently whiter parts) - source: Wikipedia

The paleomammalian complex (limbic system) consists of olfactory bulbs, hippocampus, hypothalamus, amygdala, anterior thalamic nuclei, fornix, columns of fornix, mammillary body, septum pellucidum, habenular commissure, cingulategyrus, parahippocampal gyrus, limbic cortex, and limbic midbrain areas
the limbic system (source: Wikipedia)
> 5 votes

---
Tags: brain
---


# Question
Title: Which research article showed that East Asian parents used verbs more to their infants and toddlers?
Which research article showed that East Asian parents used verbs more while White parents used adjectives more and had implications for causal and math learning?

Please give the citation of the relevant article.

# Answer
**Dimensions of Human Behavior: The Changing Life Course By Elizabeth D. Hutchison** Chapter Language skills

Hoff, E. (2006). How social contexts support and shape language development. Developmental Review, 26(1), 55-88.
> 4 votes

---
Tags: cognitive-psychology, developmental-psychology, language, mathematical-ability, cognitive-development
---


# Question
Title: Term for an inability to accept ideas that are outside the norm
This one might need a bit of an explanation. I read a statement someone made a few months ago about the normalization of concepts in society. That is if you have ideas that don't exist within the range of socially acceptable opinion, people won't tend to understand or accept them, and so discourse is usually confined to that range.

So I'm wondering if there is a term for either:

An inability to accept ideas that are outside the norm of socially acceptable opinion.

OR

The phenomenon in general, where public discourse is usually limited by a range of what's acceptable.

# Answer
What prompted the original question was someone I follow on Twitter mentioning the term I was referring to, which I had forgotten and wanted to remember.

Luckily, he recently re-posted the concept. It's called the **Overton Window**.

> The Overton window, also known as the window of discourse, is the range of ideas the public will accept. It is used by media pundits.\[1\]\[2\] The term is derived from its originator, Joseph P. Overton (1960–2003),\[3\] a former vice president of the Mackinac Center for Public Policy,\[4\] who in his description of his window claimed that an idea's political viability depends mainly on whether it falls within the window, rather than on politicians' individual preferences.\[5\] According to Overton's description, his window includes a range of policies considered politically acceptable in the current climate of public opinion, which a politician can recommend without being considered too extreme to gain or keep public office.

I'd think you could also apply this concept to the psychology of individuals. If you push their line of thinking too far, too fast, it will often be rejected.
> 1 votes

# Answer
At an individual level, a person that refuses to even consider an idea that goes against his or her existing beliefs would be called close-minded or narrow-minded.

Intolerant and prejudiced can also be used, but intolerant tends to be applied when discussing religious or political ideas, and prejudiced when talking about racial relations.

Conformist can also be used, and is a more neutral term. It's also a bit vague, so you'd have to specify which idea or range is being conformed to.

A public discourse limited to an acceptable range of subjects would limited to "safe topics".

A person who can accept or generate ideas outside of socially acceptable opinions can be labelled a free-thinker. Depending on how far outside the norms the ideas are, the person and may be branded a "radical" or even "pervert" in order to indicate society or government's disapproval of the individual.
> 2 votes

---
Tags: social-psychology
---


title: Emotions and reflexes - difference

text:
# Question
Title: Emotions and reflexes - difference
It seems to be the obvious for many psychologists, but on what grounds emotions are considered to be different than reflexes?

# Answer
In a simplified example, a tennis player's eyes see the tennis ball's movements, and is working with the brain to track the speed and trajectory. The brain is then reacting to these cues along with all other available cues, to send signals to the nerves responsible for moving the body in the required way to respond to these cues.

If however, something happens externally to the tennis game, which is then interpreted by the amygdalae and hypothalamus as a threat to the host's wellbeing, the brain's attention is immediately moved from the tennis game to the threat in order for it to react in the best way possible to protect the body from the perceived impending danger.

Now, the brain may not be immediately conscious of the threat in a psychological sense as it may not have time to think about the threat in a psychological way, but nevertheless, the brain will be conscious of the impending danger and will respond accordingly in the most efficient way possible.

This is reflex reaction.

Emotional reactions are psychological reactions to stimulae which the brain receives, whereas reflex reactions are reactions which result from stimulae which the brain currently doesn't have time to process psychologically.
> 2 votes

---
Tags: emotion
---


# Question
Title: Does the strength of the simultaneous contrast illusion vary with the length of time it is viewed?
I have done several searches without finding any papers addressing this question..

I'd like to know if there is any evidence to suggest that the strength of the simultaneous contrast illusion (or any similar effect) is affected by the length of time that a person looks at the display.

For example, are people more likely to report a contrast effect / perceive the effect more strongly (as in perceive a bigger difference between targets) if they stare at the display for a few seconds as opposed to seeing a much more brief presentation of the display? Or vice versa?

If you're aware of any literature or a good starting point for this, I'd be grateful if you can point me in the right direction.

Equally, is there any literature addressing a similar question for different types of illusory effects?

# Answer
> 2 votes
I'm still not 100% with this answer but this is what I've got: Research into time effect on illusion is sparce, but from what i have found I think it depends on the type of illusion. I found a paper by McCauley and Henrich which discusses the way in which illusions are processed - diachronic being over time and synchronic being instantly. They have used Müller-Lyer illusion as an example.

> Diachronic penetration contrasts with the synchronic penetration of those input systems. Because subjects either (a) acquire some explicit theory (that has implications for their demonstratively illusory experience with some stimulus),6 or (b) gain wider perceptual experience including, possibly, wider experience with the illusion-inducing stimulus and, presumably, thereby obtain a new implicit conception of it,7 or (c) both, they would, in the case of synchronic penetration, instantly or at least very quickly cease to experience the illusion or, at any rate, experience a mitigated version of the illusion—e.g., the perceived disparity between the lines in the Müller-Lyer illusion (below) would measurably decrease.

the Müller-Lyer illusion is a persistent illusion, Fodor (1983) also cites the Ames room and the phi phenomenom (perceiving a series of still images, when viewed in rapid succession, as continuous motion) as persistent illusions. It appears that the simultaneous contrast illusion is a persistent illusions.

The simultaneous contrast illusion is induced by the distribution of the peripheral gray values which indeed show a continuous shift of gray levels, although in a reverse direction. The phenomenon of simultaneous contrast helps us to make the contrast clearer; helping us to identify figure-ground relations more easily, more quickly and more securely (Carbon, 2014). Visual processing is very fast, it generally starts at about 75-80 ms (Vanrullen & Thorpe, 2001).

There are some illusions that once they are 'figured out' wont work again (such as change blindness).

Some illuisons require sematic knowledge to fill in the gaps for example the illusion below.

> What we will perceive at first glance is mainly guided through the specific activation of our semantic network. If we have been exposed to a picture of a man before, or if we think of a man or have heard the word “man”, the chance is strongly increased that our perceptual system interprets the ambiguous pattern towards a depiction of a man—if the prior experiences were more associated with a rat, a mouse or another animal of such a kind, we will, in contrast, tend to interpret the ambiguous pattern more as a rat (Carbon, 2014).

At first glance you perceive the illusion as one thing but you may go onto to perceive both things. This would require more time - and this would be the illusion changing over time.

What I've concluded about the simultaneous contrast illusion and others like it is that perception of them is two things - fast and persistant. What I've drawn from this is that they don't change over time, and that not many researchers are interested in whether or not they change over time, possibly due to coming to the same conclusion?

References:

McCauley, R. N., & Henrich, J. (2006). Susceptibility to the Müller-Lyer illusion, theory-neutral observation, and the diachronic penetrability of the visual input system. Philosophical Psychology, 19(1), 79-101.

Carbon, C. C. (2014). Understanding human perception by human-made illusions. Frontiers in human neuroscience, 8, 566.

Vanrullen, R., & Thorpe, S. J. (2001). The time course of visual processing: from early perception to decision-making. Journal of cognitive neuroscience, 13(4), 454-461.

# Answer
> 1 votes
I don't have an answer, but I do have a potential starting point to offer.

I think the answer will depend on how/whether adaptation changes per luminance level. It might be the case that brighter surfaces lead to more visual adaptation. Or it might be that adaptation depends on perceived and not only presented luminance. Or it might be that the contrast itself is the thing the visual system adapts to (again, physical or perceived).

Here is a classical Science paper that combines luminance, contrast, visual adaptation and time into a single paradigm:

> Anstis SM (1967) Visual adaptation to gradual change of intensity. Science 155:710-712

It describes the recovery from adaptation through a change in afterimage luminance over time. If I remember correctly, the stimulus was a gradually dimming light that was repeatedly displayed - the afterimage was a gradually brightening spot. (Or maybe it was the other way around)

Hopefully you can find more from this point on. Stuart Anstis has done more work on the topic since that paper.

# Answer
> 1 votes
If I understand the question correctly, you are asking about the perceived intensity of a stimulus, depending on time of its display. I would suggest you look for literature which discusses temporal summation. In non-psychological tongue it's called Bloch's Law (Response=Intensity\*time of display).

Maybe this would serve you: Barlow, H. B. (1958). Temporal and spatial summation in human vision at different background intensities. The Journal of physiology, 141(2), 337.

---
Tags: cognitive-psychology, perception, vision
---


# Question
Title: How does the brain project pain on to a particular part of the body?
How does our brain translate periheral sensations due to injuries into pain perceptions? As an *in silico* analogy - if a stimulus is applied to a sensor it can be transmitted to a microprocessor. The micro processor then processes the information. However, a microprocessor will not cause the sensor to "feel" that stimulus. In other words, the processed information of the sensor is not projected back to that sensor as a perceived stimulus. Hence, in electronic circuits the information is processed unidirectionally. In contrast, in the peripheral nervous system sensory inputs are processed in the central nervous system, ultimately resulting in perceived sensations on the location of the sensor. Thus, apparently, the peripheral and central nervous systems operate in a feedback loop.

**How does our nervous system do this? In other words, how does it localize the source of the stimulus (*e.g.*, pain) and turn that sensation into a perception on that location, rather than just unidirectionally process the information?**

# Answer
**Short answer**
Peripheral sensory information is projected unidirectionally to the brain. A sensory strip of the brain contains a topographical representation of the surface of the body that facilitates the localization of peripheral stimuli. Hence, there is no feedback from the brain to the periphery necessary to locate the source of a peripheral stimulus.

**Background**
The sensory systems in the skin project unidirectionally to the somatosensory cortex. In the somatosensory cortex there are so-called topographical maps. These maps contain the neurons that connect to different parts of the body. Typically, neurons receiving information from one part of the body are clustered together in the brain. For example, the sensory outputs of the peripheral touch receptors in the finger digits ultimately synapse onto cortical sensory neurons that are close together. Touch receptors in the toes for example are processed farther away (Purves *et al*, 2001). A famous graphical presentation is the somatosensory homunculus (Fig. 1), showing the areas of the sensory cortex devoted to processing sensory inputs in different bodily parts, including touch;

Fig. 1. Sensory homunculus. source: Russel & Dewy (2007)

The sensory cortex, hence, is a highly structured cortical area, in which sensory information (including outputs from touch, pain, heat and cold receptors for example) is funelled to a topographical representation in the brain. See for a nice introductory this video from Khan Academy.

To answer your question - there is **no feedback** from the brain back to the periphery necessary to process peripheral sensations into localized perceptions. The bodily map is maintained in the brain and contains all the information necessary to pinpoint the stimulus locus on the skin. This localization is more accurate when more peripheral fibers are present, *i.e.* when receptor density is higher. This is centrally reflected in the sensory strip in a larger area of the cortex being devoted to bodily parts with denser receptor innervation. This is the reason why the homunculus is so distorted (Fig. 2). For example, the lips, tongue and finger tips are highly sensitive and contain high densities of peripheral receptors. In effect, relatively large areas of the somatosensory cortex are dedicated to processing their inputs.

Fig. 2. 3D representation of the sensory homunculus. source: University of Calgary

**Reference**
**-** Purves *et al*., *Neuroscience*. 2nd ed. Sunderland (MA): Sinauer Associates (2001)
**-** Russel & Dewey, *Psychology: An Introduction* (2007-2014)
> 5 votes

---
Tags: neuroscience, perception, neurophysiology, sensation, pain
---


# Question
Title: Why can I see the number only when I don't look directly at it?
I've recently found the following image:

I can easily see the "17" in the image if I'm scrolling and (much less easy) when I move my eyes and don't look directly on it. Why is that the case?

In case you don't see it:

# Answer
> 1 votes
You can see the number better when you move the image or your eyes, because with this action you reduce the overall contrast of the image. The "image" in brain is a composition of many images which are acquired in small time periods, and the result can be approximately described as an average of many still images. So they are kind of blurred together. When scrolling it can also help to reduce contrast, because in short time periods the LCD pixels cannot reach the full contrast, so it appears in lowered contrast.

The contrast of stripes in your initial image is very high. Actually *contrast* is the synonym for *information*. So the underlying number 17 is simply lost in dominant information.

To demonstrate it better, one can play with different image filters which can reproduce the movement effect. A good one is Photoshop's "Motion blur" filter, here is the result for Motion blur at 45 degrees:

---
Tags: optical-illusion
---


# Question
Title: A measure of how personally people take critisism
This is my first post to Cognitive Sciences, i'm a Biologist by trade.

In Biological sciences, I have noticed more and more that people take criticism very personally. If I were to criticize a plumber's use of an 1/2" pipe when they should have used a 3/4" pipe, or a computer technician's use of a 600W power supply rather than a 1000W power supply, they might take it personally, but I feel they are far more likely to respond from a facts-based point of view. In biological sciences however, I more and more get the impression that people think attacking their work is a personal attack on their character.

Perhaps it's the high-stakes nature of a job. To have a paper retracted in the early stages of your career as a researcher is to essentially stop being a researcher. Which since most people get their PhD around 30 is a pretty big blow to anyone's life plans. Not so with a plumber who does a bad job one day.

So i'm wondering if this can be quantified. Some metric of how personally people take criticism, or how objective they can be. Does such a phycological test exist?

Thank you so much!

# Answer
> 1 votes
I do not know whether such a test exist, and I also would be wondering how you could convince someone to take a "how offended do you get" - Test :P.

Anyway, this is a weird topic to quantify, because of your special "needs". You have on the one hand the "Offendedness", the measurement of how a person is likely to respond negatively and get in a personal defense position when you give them criticism. This really depends a person's development, If someone as you said puts in 15 years of hard work to get a PhD they may be really defensive of criticism against their work. If you would criticise the same people maybe of their ability to play guitar which they have maximum 100 hours on, they may not react defensively. So you would need to determine special offendedness of criticism in some subject like Biology. Also the measurement is really hard. You may be able to diagnose people with emotional dysfunction by letting them look at eyes and guess the emotion (and even here, the error rate is probably high), but how are you assuring that people would honestly and self reflecting in a test of how offended they may get. People are biased against themselves and others, the human is not a objective living thing, if you would generalize it, in my experience even the most intelligent and even the most objective people I met are nearly the ones who are the most subjective / biased in the "right" direction. You often see such scientist debating against religious people and not finding arguments.

Then the second thing you touched on is the objectivity. Objectivity in itself is subjective, sounds weird but let me explain. People who think they are objective most of the time are subjective thinking. And objective people are the ones who know that they are subjectively thinking because they know it is really hard to not be subject to the mind-boggling biases of the human mind and perception. That being said, it is non-sense to ask the people about their own objectivity, and the only opportunity is to do it through an indirect test.

But there lies another Problem. People are going to act differently if they are in front of a test. You can not expect to get the same answers like to kill their family for the life of humanity in a real situation and on a computer test. On the online test they are way more likely to say yes, but in reality they are surely not objective enough to overcome their subjectivity, who can you expect to kill their family for the greater good?

The Complexness of the tests makes it really hard to do them without the people acting differently like in the second example or being biased against themselves in the first example. You always are able on your own empirical data to determine the tendency of people being offended or not but I believe because of the complications it is near impossible to find a objective scale to determine it.

---
Tags: social-neuroscience
---


# Question
Title: Upwards of what d' values constitute "good" sensitivity?
In signal detection theory, d' (sensitivity) is computed in terms of z-scores, to allow comparison (subtraction) of hit rates from false alarm rates. Even so, the interpretation of the d' is not straightforward: I was not able to find any absolute guidelines in terms of how much d' needs to be for it to mean "good" sensitivity.

From eye-balling a bunch of papers, it seems that d' should be above 2 or at least 1.5, but it's not at all clear. The only absolute reference is of course d'=0, which corresponds to chance.

Also, at the group level, is a good enough (i.e. above chance) performance necessarily indicated by a significant 1-sample t-test against zero?

# Answer
> 1 votes
There is no standard definition for a "good" value of d'. The index of sensitivity d' can be related to percent correct under certain conditions (unbiased observer, equal probability of signal and no signal trials, and a single observation). Under these conditions values of d' of 1, 1.5, 2, and 2.5 equate to a probability of correct of 0.69, 0.77, 0.84, and 0.89, respectively.

Historically, "threshold" was often defined as a probability of correct of 0.75. This is the midpoint of the psychometric function and in a yes/no task and the point with the steepest slope. With the transformed up-down method (Levitt, 1971) it is much easier to track a a probability of correct of 0.707 or 0.794, than a probability of correct of 0.75. These equate roughly to a d' of 1 and 1.5. Things got messier as people switched to 2-interval 2-AFC paradigms.

Another way to think about this is that the index of sensitivity d' is essentially the same thing as Cohen's d. Cohen (1988) proposed that values of Cohen's d of 0.2, 0.5, and 0.8 were small, medium, and large effects, respectively. Again, there is no obvious mapping of "good" onto small, medium, and large.

---
Tags: signal-detection
---


# Question
Title: How do you raise the stakes in an experiment without actually paying people money?
I am trying to run a psychology experiment for one of my courses and it involves people trying to guard some "treasure" of theirs and trying not to lose it.

My problem is that I can't ethically (or legally) force them to offer up their own money and then actually penalize them for not doing well. At the same time, many of the participants that I've run so far have figured out that it's all a ruse and it's fake and they're not going to actually lose any money so the data may not accurately show how people react in those situations when there is something on the line. Or I could give them a hypothetical scenario in which their job is tied to how well they do but again, it's not real so people often just don't try.

Ideally, I would have some sort of funding for this where I can offer them $10 if they do well and slowly start taking away money as they fail to give them some incentive. However, I don't have any of that (it's a course project) and I'm trying to figure out how to incentivize them.

Any help or ideas would be greatly appreciated. Thank you!

# Answer
Make them create something with their own hands, something hard to make and use that as currency.

I first became aware of this type of experiments from a ted talk by Dan Ariely which I recommend you watch, specially the last part:

What Pushes Us To Work Hard — Even When We Don't Have To?

The gist from these behavioral economics experiments, is that we value things we make substantially higher than an impartial evaluator,even more if making them was difficult,challenging or rewarding; so if you don't have money but have willing experimenters, you could possibly make them create something, let them assign a value and then use it as currency.

You experiment would be as follow:

* Create something - Origami,painting, sculpture of themselves
* Assign Value - Ask them how much would they sell it for
* Substitute for currency - Take their thing away from them, now you have something you can reward them with or even fraction.
> 1 votes

# Answer
I have run a number of studies with incentive paradigms. There are several ways to do this without spending any/very much money.

One of my favorite methods that works quite well is called a "hall of fame" manipulation. The paradigm is set up such that participants earn arbitrary points during the task. After I explain the rules of the game, I explain that they will have a chance to make our hall of fame, which is simply a high scores list. It's made up, but it comes up on the screen for them to view, and they are asked to enter in a user name in case they have a high enough score to make the list. Of course, for anonymity I don't actually record their user name or update the list based on participants' performance. At my school, undergraduates seem highly motivated by this because they are competitive.

Another thing we do in my lab is associate arbitrary points with earning candy at the end of the experiment. I like this manipulation less because many undergraduates are trying to watch what they eat, and are not very motivated by this. However, in combination with the hall of fame list, it seems to work quite well.

If you are able to get a little bit of money, what you can do is buy one Amazon gift card for say, 50 or 100$ and tell participants they'll win raffle tickets which you will draw from to select one winner after you've run your experiment. This has obvious pros and cons, namely, it's good that you don't have to pay each participant, and it's bad because some participants will decide that they have no chance of winning the raffle and they won't be motivated by it at all.

Finally, another option that is good for if you want to have several levels of incentives is to use symbols during the experiment such as: \\$ for low incentive, \\$\\$ for medium, and \\$$$ for high. In reality these amounts can correspond to pennies, allowing a participant to earn, say, $10 max over the study, but they don't have to see on each trial how minuscule the money is. The symbols will motivate them more so than the amount of money would.

Given that you are doing this for a course, I recommend using points and a high scores list.

One thing that is annoying about doing an incentive manipulation is that if you fail to find an effect, it may be that there is no effect of incentive, or it may be that your incentive wasn't strong enough; you'll have no way of knowing. As with any study, a good idea is to have some other aspect of the data that you're interested in studying so even if your incentive manipulation isn't successful, you can still address some other question.

Hope this helps! Good luck.
> 1 votes

---
Tags: experiment-design
---


# Question
Title: Why do suicide has been kept in natural selection?
Since I've heard about evolution theory, I tend to think about new things with the help of this theory. While not being always accurate, I find the reasoning that makes this theory possible very interesting.

We can ask a question like `Why do humans have 2 eyes?` and answer hypothetically that it was more advantageous for creatures to have 2 eyes than having 1 or 3. We can imagine that having 1 eye wouldn't allow to see the depth and make the creature able to live even when losing 1 eye. This answer isn't correct but makes sense.

We can do the same with behavior. `Why do we tend to be jealous?` We can imagine that forcing your sexual partner to stay with you gives your more chances to spread your genes. I'm not saying that this is the only answer but that's one hypothetical answer that makes sense.

However, what about suicide? From what I have read, people tend to suicide when their amount of pain is higher than what they can support. I don't see any reason why creatures(or anything from bacteria to human) would be advantaged from committing suicide. Why didn't the natural selection keep the individuals that can endure anything since they have more chances to stay alive and spread their genes?

# Answer
This assumes that tendency to suicide is hereditary. It seems that currently, the consensus is that suicide risk can be increased by environmental factors as well as by family history, so it may only be partially encoded in our genes.

For that part of the 'suicide genes' that does survive the natural selection, some of the possible explanations could be that people who commit suicide may have already had children, so their genes have been passed on to the next generation.

Another explanation could be, linked to what Yuval Noah Harari mentioned in "Sapiens". Hunter-gatherers were constantly on the move and it was not uncommon for them to kill or leave behind the elderly or individuals who would otherwise be a burden or slow down the tribe. It became a social norm, potentially to the point where the sick individuals would be ready to commit suicide themselves. The tribes which practised this were able to hunt and gather more, increasing their chances of survival.

All this is, however, a speculation, it is very hard to prove the evolutionary causes of suicides under scientific rigour, especially when running a controlled study is almost impossible. Even if we were able to run a controlled study, we'd most likely find that there is a large number of factors that allowed suicide genes to prevail.
> 0 votes

---
Tags: evolution
---


# Question
Title: What causes people to feel depressed without there being a problem?
I have noticed that some people have lives that appear perfectly fine, yet they feel depressed. In my specific case the feeling typically lasts for a few days and then magically disappears, only to reappear a couple of weeks later.

* In the absence of a real problem (e.g., loss of a close friend, physical sickness, etc), what causes these periods of negative affect?

# Answer
"Their lives are perfectly fine" is a hard to test thing. Hard to compare. How people feel and respond is deeply contextual.

However there are several potential reasons:

* They may be 'wired' to feel stress or respond emotionally (i.e. Due to the way their brain has developed).
* A feeling of not being in control (This is often hard to perceive from outside and removed from concrete factors). The causes and triggers of this are varied and complex.
* A physical response. e.g. Things like a sensitivity to Gluten can cause incredible changes to our emotions and physiology. Often this manifests in good and bad periods.
* Negativity can be a reflection of the context or surroundings. Those same people may appear positive in a different context.
* Mental illness can manifest in uneven patterns. This spans from mild (common) to severe symptoms.
> 6 votes

# Answer
I would also like to point out that there is a clear difference between a psychological depression and an existential one. I would like to point out the definitions of James Park of the University of Minnesota; please have a look at the table at the bottom of this page.

So then, people with perfectly fine lives might well end up with a "clinical existential" depression.
> 3 votes

# Answer
Some people with "without a problem" have fallen under **Gut Health/Gut Microbiota**.

See study:

***"A randomized controlled trial to test the effect of multispecies probiotics on cognitive reactivity to sad mood."***

> **"Conclusion: These results provide the first evidence that the intake of probiotics may help reduce negative thoughts associated with sad mood. Probiotics supplementation warrants further research as a potential preventive strategy for depression."**

Also see: ***Depression, The Microbiome & Leaky Gut***

**References:**
> 2 votes

---
Tags: emotion, abnormal-psychology, depression
---


# Question
Title: Searching for real biological neuron firing data [numeric]
I am searching for real neuron firing data, so I can look at each neuron for fire timing (frequency) and incoming/outgoing signal-strength. I already found short youtube videos of real neuron firing footage (measured via calcium), but I am searching for numeric data.

**Data-Requirements**

* Region is not important
* the longer time range, the better

# Answer
> 1 votes
The website crcns.org hosts open source data recorded from neurons in various brain areas.

---
Tags: neuroscience, cognitive-neuroscience, neural-network, data
---


# Question
Title: Does logical thinking or counting develop first in children?
During the course of normal brain development, what comes first:

* logical thinking or
* counting?

# Answer
Counting, easily. It's a matter of rote and repetition, dominated by procedural learning. Critical thinking requires more advanced circuitry and learning. There is a lot of really rapid neural development still occurring in the first couple years and children are learning from society and parents and experience in the meantime. During this time, they can easily count and say the alphabet.

Logical thinking isn't apparent until around 3 or 4, though I suppose a robust discussion would require a formal definition of what constitutes logic.
> 4 votes

# Answer
For a real answer on this topic, you need two things: one is to understand your question, and the other is an understanding of Jean Piaget's masses of research into the development of intelligence (from birth to adulthood). Regarding understanding your own question, you must appreciate that decades of philosophy and psychology reveal that you cannot separate logic from mathematics. Even at the simplest of levels , young children around 4 years old will demonstrate semi-logical skills together with primitive counting skills. The reason for all this is that the level of abstraction above perception (i.e. in thinking) required for both logic and number is the same, and there is a hierarchy of such abstractions that can be traced throughout the development of intelligence common to every individual. Jean Piaget is the one you want to read, and epistemology (study of knowledge) is the domain you are asking about.
> 2 votes

# Answer
Logical Thinking is a very broad class of phenomena whereas counting is a very specific one. Logical Thinking dependes on the invidual having logical operations, which follow a course of development from early childhood, as proposed by Piaget. Counting itself has been a subject of research that shows that indeed young children can learn to count without understanding what number is. For example, a child may count two rows of items and count both as having "six", yet when one of such rows's elements are spaced, thereby removing the optical correspondence between the items, that same child will deny that both rows still have the same amount. A review of this research and other topics related to early mathematics learning can be found in http://www.nuffieldfoundation.org/sites/default/files/P2.pdf
> 1 votes

---
Tags: developmental-psychology, brain-development
---


# Question
Title: Where could I collect UK participants for my survey?
I am looking for survey participants from the UK. Is there a place I can publish my survey in order to get UK participants?

# Answer
> 4 votes
You could obtain paid participants from https://www.prolific.ac/

That site allows you filter by country.

The prices are reasonable, especially if your survey is short and you don't need too many participants.

---
Tags: survey, social-networks
---


# Question
Title: Has a hypersensitivity to depictions of embarrassing situations in media been described in the psychology literature?
Has a hypersensitivity to depictions of embarrassing situations in media been described in the psychology literature?

How would I go about researching this?

# Answer
> 3 votes
If you have access to online databases via a university or public library, I would recommend searching for scholarly articles using keywords such as “embarrassment” and “media.” Using my university’s library website I was able to search two major psychology databases, Psychology and Behavioral Sciences Collection and PsycARTICLES. First I searched using the term “embarrassment” by itself, which produced the largest and broadest set of hits. Then I tried combinations of “embarrasement” plus other keywords, including “media,” “art,” “film,” “television,” and “sensitivity.”

While I did not find any articles specifically pertaining to hypersensitive reactions to embarrassing situations in media, I did find some that seem tangentially related, and which may be of interest. The lack of results also points to a need for scholarship in this area, if you are looking for something to research!

My search yielded multiple articles about the feeling of embarrassment itself. One that seemed promising is "The Unwanted Exposure of the Self: A Phenomenological Study of Embarrassment” by Robbins and Parlavecchio. From the abstract:

> Through a synthesis of prior theory and empirical research, these authors propose a model of embarrassment in which embarrassment is understood to signify the core, essential theme of a self that has been exposed to unwanted attention. Through an empirical, phenomenological method of analysis of data from 6 undergraduate college students, the authors identify 8 themes of embarrassment and relate them through a structural description of the phenomenon. The findings support the unwanted exposure model of embarrassment. (Robbins and Parlavecchio 2006)

This article may offer a useful framework for understanding of how embarrassment is viewed in psychology.

Only one article I found made mention of embarrassment in media, and it was Tom Ballingall’s book review of Documentary's Awkward Turn: Cringe Comedy and Media Spectatorship by Jason Middleton. In this review, Ballingall writes that the book examines the evolution of “cringe comedy” and mockumentary, and the various dimensions of spectatorship the genre engenders. He states:

> “When individuals sense and feel the rules of social life and/or documentary filmmaking breaking down (i.e., when awkwardness emerges), they are confronted with nothing less than the constructedness of documentary's criteria for truth and authenticity.” (2015)

Middleton's book may be a good place to start.

Sources: Ballingall, Tim. "Documentary's Awkward Turn: Cringe Comedy and Media Spectatorship." Journal of Popular Culture 48, no. 1 (February 2015): 209-211. Psychology and Behavioral Sciences Collection, EBSCOhost (accessed December 5, 2016)

Robbins, Brent Dean, and Holly Parlavecchio. 2006. "The Unwanted Exposure of the Self: A Phenomenological Study of Embarrassment." Humanistic Psychologist 34, no. 4: 321-345. Psychology and Behavioral Sciences Collection, EBSCOhost (accessed December 5, 2016)

---
Tags: abnormal-psychology
---


# Question
Title: Could any kind of learning be framed as learning a language?
People learn (or actually acquire) languages naturally. As we grow up, we learn also multiple other skills which we then use in everyday life.

A lot of these skills are often compared to a language, for example:

* Mathematics
* Reading
* Playing musical instrument
* Programming languages
* Law
* Playing chess (proven to rely on patterns)
* Dancing
* Painting or, more generally, producing works of art.

All of the above have been compared at one point to a language. They are used to communicate ideas, emotions and information.

The language is used for communication. In the same way, one person knowing the law/programming language/accounting wouldn't actually possess any useful skill without the presence of other lawyers/computers/tax system. So one can argue that all these skills are relevant and can be evaluated only in the presence of other people who receive the message expressed using them.

In the same way, if one person invents their own language but nobody else understands it, we wouldn't classify it as a language.

So, could it be that most of the skills we learn could be described as a language? What would be arguments against it? Is there any evidence I can look into with regards to similarities between learning different skills and learning languages?

# Answer
> 1 votes
It appears that the language and learning new skills would often (depending on the skill) be managed by different parts of the brain. It is, therefore, unlikely to be similar.

A good description of how the learning process works from neuroscience's point of view can be found here: http://neuroscience.uth.tmc.edu/s4/chapter07.html.

This same course also describes how the language is managed in the brain in this chapter: http://neuroscience.uth.tmc.edu/s4/chapter08.html.

Based on the above, it doesn't seem to be the case that the mentioned skills are similar to language, at least not in terms of how the brain processes them.

# Answer
> 1 votes
I would argue that as soon as you start to consider model-free learning, such as reinforecement learning (e.g. Pavlovian Conditioning) that the language idea breaks down. For example, I don't think that learning that a bell is often paired with food can be usefully thought of as learning a language without some serious contortion of the meaning of what a language is.

With this is mind, if you consider that language is a very high-order cognitive ability that relatively few animals poses, yet even sea snails can learn (just ask Eric Kandel), I would say that the majority of learning cannot usefully be considered learning a language.

However, from your question you seem to only be concerned with complex skill learning. At this point it's probably more useful to consider what criteria are required to define something as language (e.g. a grammar, syntax, symbolic conveying of information), and then see if the skills that you are interested fulfill those criteria.

---
Tags: learning, language
---


# Question
Title: Do non-human primates exhibit the Kiki/Bouba effect?
After understanding that cats cannot experience the Kiki/Bouba effect, I wonder if smart non-human primates can experience it. There is evidence suggesting that Chimpanzees associate high pitch with high luminance, and low pitch with low luminance.. However, the kiki/bouba effect is a more complicated phenomenon.

So do chimps experience it, even at a lower level, or is the Kiki/Bouba effect limited to human beings only?

# Answer
**Short answer**
As far as I can see, testing the existence of the kiki/bouba effect in primates is technically impossible, because of their lack of speech and/or potential bias due to training effects inherently necessary for animal behavioral experiments.

**Background**
The reasoning in that other question was basically as follows:

> Cats \[*read: non-human animals*\] don't have that kind of repertoire of phonemes. So regardless the \> similarity in some brain areas \[*of animals other than modern day humans*\], I dare to say a bouba/kiki or baluba/takete effect can never be found in cats \[or any other non-human animals\].

Hence - along those lines the answer to your question is 'no', as the bouba/kiki effect can simply not be tested in its current form in non-human animals, because the latter are not capable of uttering the words bouba or kiki. An interesting note on this are parrots and related species that are capable of reproducing human speech. However, they simply imitate the sounds, just like other species of birds imitate the sounds of ringtones and the likes. That, however, does not mean they associate those words or sounds with the meaning they have to us.

Further, as suggested in that previous answer; synesthesia and cross-modal associations can certainly not be ruled out by any means.

An interesting side track on your question would be the question wether there are cross-cultural differences *within* the human species. For example, folks speaking languages unrelated to Western languages, like the tonal language Chinese Mandarin, *may* produce a different outcome in the same bouba/kiki test.

The comment from ArnonWeinberg is an interesting one - why not train an animal to point at one of the two graphs when hearing bouba or kiki? Well, the issue here is that the animal needs training; the trick with the bouba/kiki effect is that naive people assign the same pointy structure to the work kiki and the blobby image to bouba. If one would train an animal the trainer needs to reward (or punish) the animal when it responds in a satisfactory way. That means the experimenter's influence on the animal's response will be paramount for the outcome of the experiment. In turn, a trained animal will respond the way it was taught, which is not the intention of this experiment.
> 2 votes

---
Tags: perception, cognitive-neuroscience, vision, hearing, cross-modal
---


# Question
Title: Is ''The principles of psychology'' by ''William James'' outdated?
I was reading about eminent psychologists and I came across William James and a book that he has written: *The Principles of Psychology*. However, Wikipedia states this book is outdated:

> Philosopher Helmut R. Wagner writes that most of the book's contents are now outdated, but that it still contains insights of interest.

The article referenced is the following:

Wagner, Helmut R. (1983). Phenomenology of Consciousness and Sociology of the Life-world: An Introductory Study. Edmonton: The University of Alberta Press. p. 218. ISBN 0-88864-032-3.

Is this true or is it still worth reading?

# Answer
> 0 votes
See this review Reference "Joseph C. Hager, Ph.D." Amazon Review -

> Why would anyone want to read a book about psychology that was first published 113 years ago? One answer is the rationale for reading any psychology book: that it provides insights into psychological issues not available elsewhere. Although many psychologists of the late 19th and early 20th century probably started their career by reading this book, it is not appropriate today as an introduction to psychology. Too many of James's viewpoints are antiquated, and his facts, outdated or incorrect. Neither is it the book to read if you are looking for contemporary psychological views or a compilation of psychological knowledge. Recent textbooks are better for these purposes. Yet, the word most frequently used to describe James's Principles of Psychology is probably 'monumental' and rightly so because not only is this a lengthy work (~1400pgs), but it also is the culmination of a long line of philosophical thinking about the Soul, Self, Mind, Matter, and related topics that began with the pre-Socratic Greeks and continued through the 19th century, when positivist philosophers and experimentalists began to explore psychologically relevant philosophical questions in more concrete terms, invoking a scientific method and rejecting metaphysics. At the end of the 19th century, a seeming riot of discussion about the meaning of life, the nature of consciousness, mind, ego, evolution, and related subjects dominated the scientific and popular culture. At this point in history, William James, an American trained as a physician and employed as a Harvard professor, examines the various philosophies of the previous two millenia, picking out those aspects relevant to psychology, comparing and sorting them to reveal their value as unambiguous theories that might be tested by research, and reflecting on how the evidence stacks up in their favor. He also advances his own, original conceptions on various issues. His work is not the first to collect speculation and evidence into a coherent psychology, and there are many previous works with "Psychology" in their titles, but James's efforts would galvanize an American discipline of psychological science that would eventually become a dominant intellectual force. James defines psychology as the "Science of Mental Life" and describes the stream of consciousness as "the ultimate fact for psychology." Out of his viewpoint, the school of functionalism in psychology developed, where the mind is conceived as a useful organ that evolves according to natural selection and grows according to discoverable rules. His orientation towards physiological and behavioral data eventually diminished the then dominant psychological method of introspection that James himself uses so frequently with great effect. Subsequent viewpoints in psychology, such as behaviorism, though taking part of their inspiration from functionalism, reject James's definition of psychology, so that by the end of the 20th century, most psychologists with an empirical orientation may call themselves "behavioral scientists," but certainly not "mental scientists." Reading this book can be disconcerting, perhaps because of his period style or Victorian sensibilities, or the frequent, unglossed short quotes and phrases in German, French, and Latin because he assumes the reader has at least these minimal language skills. Perhaps also, it is because James is not only conversant with the giants of philosophy and experimental technique who preceeded him, but seemingly, with virtually every published sentence to date bearing on the subjects of concern, and in veritable fractal detail, producing a tour de force in erudition. His is not the style of current psychology journals and textbooks, but fortunately he does translate into English many long passages he quotes from their original sources. Yet possibly the most disconcerting aspects are the subjects that James raises in this book. The new mainstream psychology after James rejects many topics as unsuitable - even for discussion - that figure prominently in the intellectual history of philosophy and psychology. James's view that the concept of Soul should be eliminated in scientific works is one point on which later psychologists heartily agree, but they also, to a large extent, throw out other concepts of central concern to James, such as mind, emotion, will, and feeling. Rare pleas by scholars with varying backgrounds (e.g., Ornstein, Tomkins) urge students of psychology to revisit issues discussed by James and address the larger questions contained therein, but such exhorations echo mostly in halls of learning emptied by Vita enhancement pressures. Renewal of interest reappears lately for some of the suppressed topics, cast into such areas as cognitive psychology or emotion theory, but James's idea that the mind is a core concept remains foreign to virtually all contemporary psychologists, and much of his emphasis seems uncomfortable from today's viewpoint. The reluctance among psychologists to embrace such philosophical and scientific issues concerning the mind is remarkably not shared by some physicists, mathematicians, biologists, computer scientists, and other scientists who in recent works have implied that psychologists may be irrelevant to elucidating such issues, if not muddle-headed, scientific dwarfs. This twist is ironic because psychologists restrict their vocabulary and investigations partly to ape their conception of these "hard-core" sciences. It is not clear whether psychology will survive the choices that psychologists have made about their subject matter, or whether psychology departments will inevitably be diced and parsed into their appropriate slots in departments of computer science, biology, medicine, statistics, and physics, but certainly, the end of psychology is nearer if tomorrow's students of psychology fail to study James's Principles of Psychology. James's work is the jumping off point for much of what forms 20th century psychology: habit, association, attention, memory, imagination, object and space perception, etc. His thoughts about emotion, feelings, the self, consciousness, and other topics remain important for today's theoretical views. On the other hand, this work predates psychoanalysis and does not include an organized account of abnormal psychology, human communication, and other topics raised in most elementary surveys of psychology. The context in which James puts scientific psychology is probably the most important lesson of this book. The Dover edition is unabridged, the only form of this work that should be considered by the serious reader.

---
Tags: psychology, history-of-psychology
---


# Question
Title: What do you call sensations without stimuli?
Sometimes, when you close your eyes in the dark, you see what looks like sparks or flashes. Sometimes when you are tired, your vision seems to shift sideways and realign, like someone bumped into a camera, although you didn't move your eyes. It seems to me that some of these apparent sensations are not caused by (external) stimuli to the sensory apparatus but rather by an "overexcited" nervous system.

Is there a term for such "mistakes" of the visual system? I don't know what terms to use to describe these phenomena in scientific reports.

# Answer
> 5 votes
**Short answer**
*Visual hallucinations* and, more specifically, *phosphenes* are the terms you are probably after.

**Background**
I'll basically provide a list of terminologies below, as your question seems to indicate you're walking on unfamiliar grounds with your research.

1. For a starters, **sensations** refer to the peripheral detection of stimuli. **Perceptions** are the higher cognitive, central correlate of those sensations involving the conscious awareness of them.
2. The sparks or flashes you're talking about may be caused **peripherally** (sensation level), but likely find their origins **centrally** (perceptual). This, because people with low-vision, or blind people lacking functional photoreceptors in their retinae can experience them too, and sometimes in exaggerated and pathological forms.
3. The visual field shifts are most likely caused by eye movements, unless you can provide solid sources to back up your thoughts that it can happen without eye movements. Likely, nystagmus or related involuntary eye movements are involved, which can be exaggerated by some physical conditions, again including blindness.
4. Now, as my knowledge is restricted to visual impairments, I can say that spontaneous spots of light are not sensations, but ***hallucinations***. A hallucination being "...*a sensory experience, possessing the compelling sense of reality of a true perception, but occurring without external stimulation of the relevant sensory organ*. Specifically, they are ***elementary* visual hallucinations**, as opposed to ***complex* visual hallucinations**. An example of the latter is the *Charles Bonnet Syndrome*, where blind folks experience complex visual scenes, including faces.
5. Back to your question on elementary visual hallucinations, they are referred to as ***phosphenes***, ***photopsiae***, or ***unformed visual hallucinations***, Typically they consist of colored or colorless bright lights, such as points, flashes, stars, and sparks. To provide some context to these terms: Phosphenes are generally used to describe benign phenomena, as well as for stimuli evoked by electrical stimulation of the retina or other visual centers (forget about the latter for the sake of simplicity, as these are not hallucinations anymore). Photospsias are generally used in the literature associated with retinal disease. Unformed hallucinations, personally, I've never encountered in my field of research, but the linked article below gives it as a last option, so I simply included it here too.

<sub>**Reference**
**-** Menen *et al* (2003), *Survey of Ophthalmology*; **48**(1): 58–72</sub>

---
Tags: neuroscience, perception, terminology, vision
---


# Question
Title: What is the optimal contrast ratio for best readability?
I have asked the same question half a year ago on Graphic Design but received no useful answer.

---

According to the W3C (and another question on this site), the contrast ratio between body text and text background should be at least 7:1 for good legibility. Google takes this up in their typography guidelines, but they also maintain that

> Text with too much contrast can also be hard to read.

Unfortunately, they don't state what "too much contrast" exactly is, and I was unable to find anything definite on the web.

**What is the *optimal* contrast ratio for best readability** – that is, neither too little nor too much contrast – for subjects with normal vision **?**

# Answer
> 5 votes
**Short answer**
Higher contrast increases readability.

**Background**
In a series of papers under the umbrella "**Psychophysics of Reading**" (link is to first paper in the series of five) the authors investigate parameters that affect readability in normally sighted folks, as well as people with impaired vision. These studies seem particularly relevant to your question.

The authors investigated reading rates as an outcome measure for readability. In paper V of the series (Legge *et al*., 2007) they tested the dependence of letter size and contrast (black-and-white) on reading rate. Rates were highest (about 350 words/min) for letters ranging in size from 0.25° to 2° visual angle. Within this range, **reading rates** proved to be **tolerant to contrast reduction**. For 1° letters, reading rate decreased by less than a factor of two for a tenfold reduction in contrast. The results were very similar for white-on-black and black-on-white text. Reading rate declined more rapidly for very small (\<0.25°) and very large (\>2°) letters with lower contrast.

Based on these findings, the intuitive answer to your question is, the larger the contrast, the better. I've never heard of decreasing contrast enhancing reading abilities, barred under some very specific conditions of ultra-low vision, regardless of Google's statements on this. Your first reference clearly supports 'higher contrast is better', without the presence of a sort of optimum.

<sub>**Reference**
**-** Legge *et al*, *Vis Res* (1985); **25**(2): 239–52</sub>

---
Tags: vision, reading, hci
---


# Question
Title: What is meant by "degrees of freedom" in fMRI?
I am reading the paper "Classical and Bayesian Inference in Neuroimaging" by Friston. In the introduction he says:

"\[...\] a trivially small activation can be declared significant if there are sufficient degrees of freedom to render the variability of the action's estimate small enough."

I have heard the terms "degrees of freedom" in the context of neuroimaging numerous times but I never understood what it actually means. I sometimes also encounter the same term in a statistical context but I assume it's not the same as what Friston is referring to here. Or am I utterly mistaken?

# Answer
> 1 votes
In a statistical context, any *independent* datum adds a degree of freedom. So when Friston talks about "sufficient degrees of freedom to render the variability of the action's estimate small enough" he simply means "sufficient sample size to cancel out noise". At least that's my take on it, based only on the single quoted phrase(!).

---
Tags: fmri
---


title: Marr's analysis for ball pursuit

text:
# Question
Title: Marr's analysis for ball pursuit
Marr (1982) identified three levels at which we can describe information processing systems, including the human mind: the computational level, the algorithmic/representation level, and the implementation level.

Now I'm wondering which level is depicted by this situation: A theory that baseball players estimate how quickly to run to catch a ball by fixating on the ball, beginning to run, and adjusting their running speed so that the angle of their gaze remains constant.

# Answer
> 3 votes
The computational level is about available information and in-principle what can be derived from that information. For catching a ball, this would be, for example, an analysis of what information is available to a fielder using a particular perceptual device, and what possible inferences could be drawn from that information. From the flux of light projected on a stationary 2D retina, is it *possible* to derive where the ball will be when? What if the 2D retina can move in response to the light, then is it possible? What if there are two eyes (i.e., stereo vision)? Your description of the procedure for catching a ball *assumes* that the information used by procedure is sufficient, but does not explicitly analyze and prove it, so your description is probably not best thought of as the computational level.

The algorithmic level is about the particular representation and process for computing an inference and making a response. There are usually many different ways to compute an answer. For example, adding two numbers can be done with Roman numerals and a difficult process, or with binary numerals using a power-of-2 place system and a simple process. Your description of a procedure for catching the ball seems closest to the algorithmic level, but the description would have to specify more details to be a fully fleshed-out algorithm.

The implementational level is about "hardware". How do the optical tracts of the brain encode and process the signal, and how does the body implement the motions requested by the brain? Your description of a process for catching the ball does not rely upon or mention these details, so is probably not best thought of as the implementational level.

(At least, that's my take on it. I think that the levels were intended as a useful framework for organizing and thinking about theories and how they interconnect. Marr suggested --if I recall correctly-- that it was valuable to do a computational analysis before diving into algorithmic particulars. But discussants sometimes devolve into heated philosophical debates about the "correct" interpretation of this or that. I hope this answer does not generate too much heat.)

---
Tags: cognitive-psychology, cognitive-neuroscience
---


# Question
Title: Is there evidence to suggest that receiving angry emails increases stress levels?
There are plenty of helpful descriptions of how to avoid angry emails. The reasoning is largely that it doesn't solve the problem. That is, sending an email whilst angry causes more problems for you than it solves.

But what about the recipient? Logically and analytically we know that people don't respond well to an emotive email. But is there statistical or experimental evidence of the changes in brain/body state (or behaviour) that occur when people receive emotive emails?

My question is: **Is there evidence to suggest that receiving angry emails increases stress levels?**

# Answer
The reaction to an angry email is just the same as reacting to any angry comment (verbal or written). It is usually seen as a provocation and triggers the urge to retaliate or invoke self-defense. The mental stress is a consequence of this situation. Often this stress is transient.

I have no nowledge of any documented evidence of stress or the level and duration of the same.
> 1 votes

---
Tags: emotion, communication, stress
---


# Question
Title: Any study related to intimacy with nature and link with how it affects hormones or other chemical equations of brain?
I was looking for some research study that links activity/response of brain stimulated due to natural scenery (or walk but i guess that is more implausible situation just to track what is going on in brain while being out of an scanner)

I googled but it results are useless. Is there any study done related to this? Please post link to resource related to the issue.

PS: I am not a person with great grasp at cognitive science but just curious to know things more scientifically.

# Answer
> 1 votes
The positive impact of natural scenery on individuals well being has been well studied. I found a few studies looking at the physiological effects of viewing natural scenes.

Electroencephalography (EEG) has been used to access the electrical activity of the localized brain cortex associated with natural and urban environments (Ulrich, 1981; Nakamura, 1992). Ulrich reported that subjects shown urban and scenes produced more alpha (relaxation) activity when viewing nature scenes. High alpha amplitudes are associated with lower levels of physiological arousal as well as feelings of wakeful relaxation.

More recently Kim at al (2010) conducted a functional magnetic imaging (fMRI) study exposing participants to either rural (natural) or urban scenery, they found that different areas of the brain were active when viewing the different scenes:

> Activation of the anterior cingulate gyrus, globus pallidus, putamen and head of the caudate nucleus was dominant during rural scenery viewing, whereas activation of the hippocampus, parahippocamus and amygdala was dominant during urban scenery viewing (p \< 0.01). These findings allow better characterization of neural activation, suggesting an inherent preference towards nature-friendly living.

In terms of hormones, cortisol, amylase and adrenaline would be the ones changed by exposure to natural scenes as these are the hormones most associated with stress (Rashkova et al, 2012; Takahashi, 2005; Takai, 2004).

Park et al (2007) got two groups of participants to spend time in either a forest or a city for a day and then swap and spend a day in the opposite environment they found that:

The concentration of salivary cortisol in the forest area first group was significantly lower than that of the group that went to the city area first even after being in both landscapes.

It's worth noting however that a meta-analysis by Bowler et al (2010) found that research looking at hormones and natural environments was not consistent:

> Meta-analysis of data on blood pressure and cortisol concentrations found less evidence of a consistent difference between environments across studies.
>
> Other hormones, or measures of hormone activation, apart from cortisol, have also been investigated such as adrenaline and noradrenalin and salivary amylase. Across these different studies and outcomes, their results provide mixed findings, with no clear, consistent difference emerging in the effect of different environments.

References:

Bowler, D. E., Buyung-Ali, L. M., Knight, T. M., & Pullin, A. S. (2010). A systematic review of evidence for the added benefits to health of exposure to natural environments. BMC public health, 10(1), 456.

Park, B. J., Tsunetsugu, Y., Kasetani, T., Hirano, H., Kagawa, T., Sato, M., & Miyazaki, Y. (2007). Physiological effects of Shinrin-yoku (taking in the atmosphere of the forest)-using salivary cortisol and cerebral activity as indicators. Journal of Physiological Anthropology, 26(2), 123-128.

Takai, N., Yamaguchi, M., Aragaki, T., Eto, K., Uchihashi, K., & Nishikawa, Y. (2004). Effect of psychological stress on the salivary cortisol and amylase levels in healthy young adults. Archives of oral biology, 49(12), 963-968.

Takahashi, T., Ikeda, K., Ishikawa, M., Kitamura, N., Tsukasaki, T., Nakama, D., & Kameda, T. (2005). Anxiety, reactivity, and social stress-induced cortisol elevation in humans. Neuroendocrinology Letters, 26(4), 351-354.

Rashkova, M. R., Ribagin, L. S., & Toneva, N. G. (2012). Correlation between salivary α-amylase and stress-related anxiety. Folia medica, 54(2), 46-51.

Ulrich, R. S. (1981). Natural versus urban scenes some psychophysiological effects. Environment and behavior, 13(5), 523-556.

Nakamura, R., & Fujii, E. (1992). A comparative study of the characteristics of the electroencephalogram when observing a hedge and a concrete block fence. Journal of the Japanese Institute of Landscape Architects, 55(5), 139-144.

Kim, G. W., Jeong, G. W., Kim, T. H., Baek, H. S., Oh, S. K., Kang, H. K., ... & Song, J. K. (2010). Functional neuroanatomy associated with natural and urban scenic views in the human brain: 3.0 T functional MR imaging. Korean Journal of Radiology, 11(5), 507-513.

Kim, T. H., Jeong, G. W., Baek, H. S., Kim, G. W., Sundaram, T., Kang, H. K., ... & Song, J. K. (2010). Human brain activation in response to visual stimulation with rural and urban scenery pictures: A functional magnetic resonance imaging study. Science of the total environment, 408(12), 2600-2607.

---
Tags: cognitive-neuroscience, reference-request, nature-nurture
---


# Question
Title: To what extent does bilingualism help in education?
There has been a lot of debate over bilingualism in education. I have read a bit on the website of the National Association for Bilingual Education and some other links to read about bilingualism. However being an amateur in this field, I'd like to know what are the major works (if not conclusive) that support and dissuade against bilingualism in education especially in the context of cognitive science?

# Answer
> 7 votes
This is a phenomenom I was able to witness first hand when I used to work in an International School, where every student had to learn Japanese and English, as well as having their mother-tongue (some had several more languages as well).

In the paper "Bilingualism and cognitive development in relation to threshold theory" (Ricciardelli, 1992), it is stated that:

> This theory (threshold theory) maintains that there may be levels of linguistic proficiency which bilingual children must attain in order to avoid cognitive deficits and to allow the cognitive benefits.

Further, in "A Systematic Review and Meta-Analysis of the Cognitive Correlates of Bilingualism" (Adesope, 2010), some links between bilingualism and some increased cognitive abilities have been suggested from research. From their abstract:

> Results indicate that bilingualism is reliably associated with several cognitive outcomes, including increased attentional control, working memory, metalinguistic awareness, and abstract and symbolic representation skills.

A link between bilingualism and how the bilingual student would tackle worded maths problems, in Cognitive Benefits and Costs of Bilingualism in Elementary School Students: The Case of Mathematical Word Problems (Kempert et al. 2011).

An important point

> bilinguals gained scores comparable to those of their monolingual peers on word problems that required attentional control skills although performing significantly below their monolingual classmates on ordinary word problems, suggesting that bilinguals have an advantage when it comes to attentional control.

However, there are potential cognitive costs in transferring knowledge from one language to another.

I hope this helps

# Answer
> 2 votes
Some cognitive scientists I heard are clear about benefits of being bilingual as exposed by @Damien or here - http://www.nytimes.com/2011/05/31/science/31conversation.html?\_r=0. They also do not hide the associated cognitive costs especially at a young age. I found the following presentation very interesting http://bilingualism.bangor.ac.uk/seminars/documents/AlbertCosta\_000.pdf (!! one image af a brain may be disturbing !!).

Hellen Bialystock is a world class researcher in Toronto (more than 100 different languages here, a unique place to work on bilangualism she says). Alert Costa works in Barcelona on Catalan/Spanish - these two researchers are part of my trusted sources of information to understand my bilingual kids!

# Answer
> 0 votes
Npr.org, has a great multi part piece on the subject, and points to a cognitive benefit in the elderly in so far as dementia preventionenter link description here

---
Tags: educational-psychology, linguistics
---


# Question
Title: Is there an R implementation of the linear ballistic accumulator model or Ratcliff's diffusion model for measuring response time and accuracy?
I am looking for an implementation of the linear ballistic accumulator model or Ratcliff's diffusion model (e.g. in R, MATLAB, or Python).

# Answer
*Here are a few options. I have not tried them yet personally.*

As mentioned below, the rtdists package in R is able to fit both LBA and diffusion models.

# Other Options

### LBA

Scott Brown has a copy of Donkin et al (2009) on his web page with some code in R, Excel, and WinBUGS for fitting the LBA model:

There's also the `glba` package on CRAN by Ingmar Visser.

### Diffusion model

The Diffussion model is available as a matlab toolbox called (DMAT).

### References

* Donkin, C., Averell, L., Brown, S.D., & Heathcote, A. (2009) Getting more from accuracy and response time data: Methods for fitting the Linear Ballistic Accumulator model. Behavior Research Methods, 41, 1095-1110. PDF
* Vandekerckhove, J., & Tuerlinckx, F. (2008). Diffusion model analysis with MATLAB: A DMAT primer. Behavior Research Methods, 40, 61-72. doi:10.3758/BRM.40.1.61 PDF
> 17 votes

# Answer
For the diffusion model, there is also Eric-Jan Wagenmakers' "EZ-diffusion model", which you can find here.

This paper compares three different pieces of software for estimation of diffusion model parameters:

> von Ravenzwaaij D., & Oberauer, K. (2009). How to use the diffusion model: Parameter recovery of three methods: EZ, fast-dm, and DMAT. Journal of Mathematical Psychology, 53 (6), 463–473. \[PDF\]
> 9 votes

# Answer
The R package diffIRT (http://www.dylanmolenaar.nl/jss1265.pdf) estimates both the Q and the D diffusion models (see his website for the van der Maas et al. paper discussing the differences between these models). R code for the EZ2 approach, which is much faster if that is important for your applications, is http://raoul.socsci.uva.nl/EZ2/.
> 5 votes

# Answer
In the subheading you also mention that you're interested in matlab / python implementations:

I've personally used DMAT in matlab at that's a nice package. However, the python based HDDM package may be one of the best around at the moment (in my opinion) and it has a good user guide.

http://ski.clps.brown.edu/hddm\_docs/abstract.html

and the paper associated with the package:

Wieki et al (2013): http://journal.frontiersin.org/article/10.3389/fninf.2013.00014/full

### References
> 3 votes

# Answer
The R package `rtdists` is another great option:

> Provides response time distributions (density/PDF, distribution function/CDF, quantile function, and random generation): (a) Ratcliff diffusion model based on C code by Andreas and Jochen Voss and (b) linear ballistic accumulator (LBA) with different distributions underlying the drift rate.
> 2 votes

---
Tags: experimental-psychology, cognitive-modeling, mathematical-psychology, reaction-time
---


# Question
Title: Death from sleep deprivation, what physical mechanism is failing that makes one not to be alive anymore?
I have been reading on wiki about sleep deprivation it would appear that one can die without sleep... I have heard that it was used as torture method by quite a few agencies, but didn't know that one could die from it....

As far as I know REM is just brain running a simulation to improve long term memory by re-firing the neuron paths to make them 'stick' better...

When death from sleep derivation occurs, what mechanism is failing that makes one not to be alive anymore. I mean there has to be some physical thing that breaks down, otherwise one would just loose consciousness and wake up in 40 hours or so...

# Answer
> 6 votes
> As far as I know REM is just brain running a simulation

During sleep hormones and neurotransmitters shift in their quantities available along the phases of sleep: slow wave sleep, intermediate stages and REM ( this happens several times during a typical sleeping session) and each phase brings corresponding highs and lows of the aforementioned chemicals.

There is not a definitive and agreed function of sleep, but currently it is heavily tied to memory consolidation and metabolic regulation as well as a supporting role in the immune system.***1***

> When death from sleep derivation occurs, what mechanism is failing that makes one not to be alive anymore.

Well, we don't really know,at least in humans it is not something we can really experiment, so most of the accounts are just that, anecdotes.

In order to try to answer the question, we unfortunately have to turn to the animal world, studies of Total Sleep Deprivation (TSD) in rats are perhaps the best researched ones, and yet there is still coinsiderable doubt about what ends up being the cause of death. ***2*** and it's relationship to sleep.

> I mean there has to be some physical thing that breaks down

To summarize a review/update of the original sleep deprivation study***3*** :

The effects of total sleep deprivation seem to have interfered with thermoregulation,caused a deterioration in the appearance of the rats, skin lesions, and changes in brain activity; infection, hypothermia and malnutrition are the leading suspects then and the thing that broke down in a roundabout way is the supporting mix of chemicals ( neurotransmitters, hormones) & brain activity that normally keep these deadly effects at bay.

Reference/Sources:

1.
2.
3.

---
Tags: sleep, dreams, brain-injury
---