# Question
Title: Do personality survey responses correlate to the success or failure of minimum wage employees?
I recently watched a friend fill out a personality survey for a minimum wage job. These surveys generally have a few dozen to as many as a couple hundred statements with which the applicant must agree, disagree, or stay neutral. The survey is designed to filter candidates. What puzzles me is what basis they use for this filtering.

Some of the questions are obvious correlates with negative employee qualities:

> * Sometimes I shout at customers to get my point across.

Well, gee, I wonder if I should "strongly agree" with that one? Others, however, are not so clear:

> * I will work hard to get a job as an executive at a large company.
> * My former bosses all say I'm the best employee they've ever had.
> * I spend a lot of time thinking through about a problem before solving it.

For example, being a self-starter might help or hinder a job behind a cash register. Exercising leadership is great until you're one of 40 people restocking the shelves. Thinking through problems is a useful skill unless the problem facing you is trivial, in which case "consideration" might be construed as "procrastination". Based on examples like these, it's not inherently obvious if these questions measure positive or negative qualities, or what the model response might be.

Moreover, the size, type, and prevalence of these questionnaires suggests a level of sophistication in the selection process that I'm not convinced it is due. Supposing they test 5-10 core competencies, qualities like leadership, professionalism, and decorum, there are more than enough responses to establish inter-survey response validity. Of course, that assumes these employers spent millions of dollars developing valid, proprietary psychometrical measures, or co-opted something in the academic domain.

So what are these surveys really testing? Tongue-in-cheek, if faced with such a test, what would agreeing, disagreeing, or remaining neutral with the statement, "Employer personality tests correlate with success or failure in the workplace?" reflect about an individual?

# Answer
### Do personality tests predict job performance in general?

There is a large academic literature correlating personality test scores with job performance. You might want to check out the meta-analysis by Barrick et al (2001). It reports the meta-analytic correlations often based on hundreds of studies between Big 5 personality test scores and job performance.

In general the correlations reported in the meta analysis are relatively small (e.g., $r=.12$ for conscientiousness is the biggest). These correlations get a little bigger if you adjust for measurement error in job performance. So, in summary, in general Big 5 measures of personality tend to predict job performance; however, the predictive validity is not that high. To see this in the context of other selection tests check out the meta-analysis by Schmitt and Hunter (1998).

### Do personality tests predict job performance for minimum wage jobs?

I'm not sure if the category "minimum wage" necessarily captures the right distinction given such a category could refer to a diverse range of jobs.

That said, in terms of breaking analyses down by occupation, at least at this very broad meta-analytic level, the correlation between conscientiousness and job performance appeared to be fairly similar across sales performance ($r=.11$), managerial performance ($r=.12$), and skilled or semi-skilled ($r=.12$) (Barrick et al 2001).

Thus, at least from this meta-analysis, these measures of personality appear to predict job performance about as well for minimum wage jobs as they do for other jobs.

### So what are these surveys really testing?

Tests can be developed in a variety of ways. In general, there are theory driven processes and there are empirically driven processes of test development. From a theory driven perspective, constructs of interest can be defined, and items can be developed. From an empirically driven perspective, various statistical techniques can be applied to check for test properties such as the degree to which items intercorrelate in meaningful ways.

Particularly in the applied setting, items or scales can be selected based on the degree to which they provide predictive validity (e.g., correlations with job performance).

More generally, personality tests provide a sampling of behaviour in a standardised way. If items have been developed in a more empirical way, then an explicit theory may not necessarily exist for the meaning of every item. Rather, it is the scale as a whole that takes on meaning which can be informed by a wide range of information including correlations within the test and correlations between the scales of the test and other measures of interest.

### References

* Barrick, M.R., Mount, M.K. & Judge, T.A. (2001). Personality and performance at the beginning of the new millennium: What do we know and where do we go next?. International Journal of Selection and Assessment, 9, 9-30. PDF
* Schmidt, F.L. & Hunter, J.E. (1998). The validity and utility of selection methods in personnel psychology: Practical and theoretical implications of 85 years of research findings.. Psychological Bulletin; Psychological Bulletin, 124, 262. PDF
> 8 votes

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Tags: measurement, personality, io-psychology
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# Question
Title: Is there cognizance or meta-awareness of classical conditioning?
Behaviorism's initial popularity was largely due to it's ability to take cognition and consciousness out of the equation; bringing it close to something that could be tested completely objectively by judging behaviors. Two of the most significant remaining findings of behaviorism are classical and operant conditioning. Because these acts can be studied in terms only of stimulus and reaction, cognition is largely ignored in related studies, especially in the traditional radical behaviorists' work.

My question is, to what extent is cognition actually at work during classical conditioning? Has it been shown that participants in studies are actually aware that they are starting to associate the conditioned stimulus with either the unconditioned stimulus or the conditioned response?

I'm excluding operant conditioning as I assume that at least for humans it is much more likely that a conscious awareness of the associations between stimuli and punishment/reward will result; perhaps this assumption is incorrect, I just thought it would help narrow the scope of the question. Feel free to correct me if it's wrong, I thought it should probably be a separate question however.

I'll also exclude Conditioned Taste Aversion as it's a rather special case and often only takes a single exposure to stimulus.

Is there evidence of conscious awareness of classical conditioning, especially while the association process is still going on?

# Answer
> 7 votes
I'm not sure what you're asking. If it's found that there's awareness of the relationships in the experiment then typically it's argued that's not conditioning and the behaviour is modified through insight. It's been a bone of contention with respect to classical conditioning and humans in the past. You might want to look at Lovibond and Shanks (2002). I think some of the thinking there is wrongheaded (how you assess awareness). Nevertheless, it's a start for looking into the topic.

If you're asking if there's an awareness of the effects of being conditioned separate from those of stimulus and response correlations, I don't think anyone has ever tested that.

Lovibond, P. F. and Shanks, D. R. (2002). The role of awareness in Pavlovian conditioning: Empirical evidence and theoretical implications. *Journal of Experimental Psychology: Human Perception and Performance*, *28*(1):3–26.

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Tags: cognitive-psychology, consciousness, conditioning, metacognition
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# Question
Title: Is religiousness a genetically heritable feature?
I know that parent beliefs have very strong influence on child, but is it possible that genetic factor also play a role? I doubt that the content of any religion could be heritable through genes nor anyone could be genetically predestined to be Christian, Jew, Buddhist or votary of any particular religion. But is it possible that some kind of sensitivity to religious aspect of life could be heritable?

I know that it is hard to distinguish genetic and environmental factor in such case, but maybe someone have already made such research for example on monozygotic and dizygotic twins or adopted children?

I've thought that if it is indeed heritable, then celibacy in the Catholic Church might be suicidal for this faith, as it eliminates the (potential) "godliness genes".

# Answer
> 10 votes
Monozygotic twin studies are the general course of action for this kind of question. Genetic and environmental influences on multiple dimensions of religiosity: a twin study concludes there is a genetic component.

A complete approach for these kind of studies is to take twins that have been separated to different households from birth and compare them to twins in the same household. I'm not sure what this particularly study does (haven't read it) but its a typical approach in behavioral biology.

A summary of the above article, also references a book where they compared monozygotic twins to dizygotic twins.

The difference between monozygotic and dizygotic twins is that monozygotic twins share almost a complete set of genetics (mutations happen) while dizygotic twins share the same amount as a normal set of siblings. The idea being that if monozygotic twins share traits at a higher statistical rate than dizygotic twins, that there is a genetic component to that trait. This, of course, does not mean the trait "is genetic" in totality. Most behavioral traits have a combination of genetic and environmental (be it developmental, social, toxicological, or else wise environmental) factors. There's also a new factor discovered recently that lies somewhere in between: epigenetics. I can't be certain, but I'd think this would appear in monozygotic similarities, probably confounding results a bit.

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Tags: genetics, parenting, nature-nurture, religion
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# Question
Title: What is the average amount of new vocabulary adults retain when learning a second language?
What are the realistic/optimal (or maximal) number of words of vocabulary that can be learned (retained and later successfully accessed) by an **adult** learner of a foreign/second language? (Unit: per day, week, or year.)

**Initial research:**

1. Read the Wikipedia article \- result: Only focuses on children and their native language acquisition (as many articles do) vs. adults, who train conscientiously!
2. Google search: Which search terms would you recommend? Results from "vocabulary acquisition" and "amount of words/vocabulary" (+daily) are in review. I did not find much yet, see below..
3. Google Scholar: In progress... ("vocabulary acquisition" and "adult vocabulary acquisition speed")

**Unverified statements found from Google search:**

"I am a student at the Defense Language Institute. We are required to learn about 80 words a day." (Source) - *I tried to access the DLI / DLIFLC website to verify this, but the website was down yesterday* (31.08.2012, 1:30 am, GMT+9)

# Answer
Try keywords like: "second language learning number of words per"

Some suggest 3-6 words per hour of reading, which is afterwards used for calculation of average per week, month, year. References of studies to support this claim are missing though: http://ip-173-201-189-182.ip.secureserver.net/archives/sla/waring120304.pdf

Several times I found references on this study: Miltion and Meara (1995).

> A longitudinal study by Milton and Meara (1995) found that adult learners of English as a second language could learn 2650 base words per year. more at: http://iteslj.org/Articles/Cervatiuc-VocabularyAcquisition.html

I remember it should be 7 words a day. If it is not, it should be at least divided into blocks of this size. If you google this number, it is mentioned on several sites, I do not remember the book I got it from.

I would be careful using these numbers, it is likely that they depend on the techniques that students and teachers tend to use.
> 3 votes

# Answer
I am an instructor at DLI... if you just took our unit vocab lists for the 63-week Arabic basic course, there are over 11,000 words listed. The vast majority are discarded well before students ever take the DLAB (Defense Language Aptitude Battery) test. In order to achieve a 2/2 (Reading, Listening) on the test, a student could be expected to have passive contextual access to at least 3,000 vocab words.
> -1 votes

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Tags: memory, learning, language
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title: Sensory Immersion Research?

text:
# Question
Title: Sensory Immersion Research?
Sensory deprivation is a relatively common technique for medititation and general consciousness-exploration.

However, I'm more interested in sensory *immersion*. That is, deliberate overstimulation as a meditative exercise.

For example, listening to two different audio streams, one in each ear (this is the original motivator for this question, as I recently found that I concentrate better when two different audio streams are being played into my ears). I suspect a relation to attentional drift and a state of relaxed/detached attention, but I don't want to jump to conclusions either.

Has there been research (by whom? available online?) on this subject?

EDIT: example of commercial service offering Sensory Immersion (www.mind-spas.com)

# Answer
I will split this answer into two parts - first, about sensory immersion as it is defined and scientifically examined. Second, I will try to address specifically what you asked for regarding the effects of sensory overstimulation and overload.

**Sensory immersion**

I don't think your definition of sensory immersion is right when you said it's a "deliberate overstimulation". There is an excellent perspectives' paper in Science, where the author refers to common definition of immersion as **the subjective impression that one is participating in a comprehensive, realistic experience** (Dede, 2009). So you don't need to be overstimulated to experience immersion - you just need a specific context and environment for it. Quick literature search indicates that the study on sensory immersion has been mainly focused around computer games and virtual environments. Dede (2009) describes a number of examples, arguing that **immersion in a digital environment can enhance education by allowing multiple perspectives (Salzman et al., 1999), situated learning (Clarke et al., 2007), and transfer**. For example, students can model expert's actions to better learn how to perform surgery, using sophisticated virtual reality with tactile surgery robots. Or they test different epidemiological hypothesis in an online social games like River City.

Immersion has also been linked with flow-like experience in computer games. Nacke & Lindlay (2008) asked participants to play *Half Life 2* while they were measured with electroencephalography, electrocardiography, electromyography, galvanic skin response and eye tracking equipment. They demonstrated measurable high-arousal positive affect emotions during intensive combat level in the game. There is extensive literature on that topic that examines cognitive effects of computer games.

**Sensory overload**

The effects of **sensory overload** is quite a different story. Lipowski (1975) argues that overstimulation increases as a direct consequence of the accelerating pace of technological advance. Author points to the numerous sources of overstimulation including overcrowding, noise and work load (Lipowski, 1975). One the largest set of experiments on sensory overload has been conducted in Japan. **Behavioural effects of sensory overload included heightened and sustained arousal, mood changes in the direction of aggression, anxiety, and sadness** (Kitamura et al., 1970; Hatayama et al., 1970). Some participants reported visual hallucinations. Authors also found that participants strongly preferred sensory deprivation to sensory overload (Kikuchi et al., 1970). Other studies showed that **exposure to sensory overload produced an increase in the scores on the scale of social alienation/personal disorganisation as well as in the cognitive/intellectual-impairment scores** (Haer, 1971; Gottschalk, 1972).

Therefore, from the cognitive standpoint, it's difficult to see benefits of sensory overload. You mentioned the music as a potential factor, and indeed some empirical studies showed **music can improve reading comprehension (Kiger, 1989), and contribute to higher performance in repetitive tasks (Fox, 1971)**. But majority of the studies clearly showed that such positive effects are only possible with low-volume and low-level of 'information load' in music (like speed, lyrics, etc.). Also, while I don't doubt your positive personal experience **with dichotic listening, the studies clearly show that it has mostly negative and distractive effect on the attention** (Asbjornsen et al., 1995).

It is also difficult to find studies showing that dissociative state caused by sensory overload could benefit meditation. Studies shows that **meditation is specific in its ability to reduce distractive and ruminative thoughts and behaviours** (Jain et al., 2007; ). Meditation aims at giving you better control over your attention, and I don't see how that could be achieved with heavy level of sensory distractions around you.

I like your question and I understand your intuition behind it, but the research seem to indicate that sensory overload is mostly a negative experience and it is unlikely that it contributes to enhancement of cognitive functioning.

References

> Dede, C. (2009). Immersive interfaces for engagement and learning. Science, 323, 66–9.
>
> Salzman, M., Dede, C., Loftin, R. (1999) Proceedings of the SIGCHI Conference on Human Factors in Computing Systems: The CHI Is the Limit, 489–495.
>
> Clarke, J., Dede, C. (2007) The Computer-Supported Collaborative Learning (CSCL) Conference, C. A. Chinn, G. Erkens, S. Putambekar, Eds., New Brunswick, NJ, pp. 141–144.
>
> Nacke, L., & Lindley, C. (2008). Flow and immersion in first-person shooters: measuring the player’s gameplay experience. Proceedings of the 2008 Conference on Future …, 81–88.
>
> Lipowski, Z. J. (1975) Sensory and information inputs overload: Behavioral effects. Comprehensive Psychiatry, 16, 199-221.
>
> Kitamura, S., Tada, H. (1970) Toh Psycho Fol 28:69.
>
> Hatayama, T., Takayama, T., Komatsu, H. (1970) Toh Psycho Fol 28:73.
>
> Kikuchi, R., Kikuchi, T., Kawaguchi, M. (1970) Toh Psycho Fol 28:84.
>
> Haer, JL (1971) Percept Mot Skills 33:192.
>
> Gottschalk, LA., Haer, JL., Bates, DE. (1972) Arch Gen Psychiatry 27:451.
>
> Kiger, D. (1989). Effects of music information load on a reading-comprehension task. Perceptual and Motor Skills, 69, 531-534.
>
> Fox, J. G. (1971). Background music and industrial effciency: review. Applied Ergonomics, 2, 70-73.
>
> Asbjornsen, A.E., Hugdahl, K. (1995) Attentional Effects in Dichotic Listening Brain and Language 49, 189–201.
>
> Jain, S., Shapiro, S. L., Swanick, S., Roesch, S. C., Mills, P. J., Bell, I., & Schwartz, G. E. R. (2007). A randomized controlled trial of mindfulness meditation versus relaxation training: effects on distress, positive states of mind, rumination, and distraction. Annals of behavioral medicine, 33, 11–21.
> 6 votes

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Tags: perception, sensation, meditation, hallucinations
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# Question
Title: Does breastfeeding lead to increased intelligence?
Several studies suggest that breast-fed babies become more intelligent children than formula-fed babies (e.g., Lucas et al 1992).

### Questions

* To what extent overall does research support the association between breastfeeding and intelligence increases?
* Is it reasonable to conclude that the association is causal?
* Or alternatively, are there better alternative explanations for the association?

### References

* Lucas, A., Morley, R., Cole, TJ, Lister, G. & Leeson-Payne, C. (1992). Breast milk and subsequent intelligence quotient in children born preterm. The Lancet, 339, 261-264.

# Answer
> 10 votes
Kramer et al 2008 is an excellent study of this question because it utilizes intervention, thus lending strength to the claim of causation, concluding that IQ was "significantly higher in the experimental group for both reading and writing".

But is it the milk itself? Some argue that it's also the skin-to-skin contact, and the mother-child bonding. Academic success has been shown to be strongly correlated with emotional intelligence (e.g., Parker et al, 2004 found $r=.33$ between GPA and EI in a large sample of high school students) and some Attachment Theory proponents claim closer parental relationships lead to stronger emotional intelligence. However, some studies demonstrate that only adults happiness is positively effected by percieved parental attachment, not emotional intelligence (e.g., Sillick & Schutte, 2006) and that emotional intelligence is correlated with a dismissive attachment style (Kafetsios, 2004).

The *Arch Gen Psych* article comments on potential mechanisms:

> Even though the treatment difference appears causal, it remains unclear whether the observed cognitive benefits of breastfeeding are due to some constituent of breast milk or are related to the physical and social interactions inherent in breastfeeding. Concentrations of essential long-chain polyunsaturated fatty acids are higher in human milk than in infant formula. Randomized trials of supplementation of infant formula with long-chain polyunsaturated fatty acids, however, have yielded inconsistent results in both term \[21\] and preterm \[22\] infants. Another potentially important component of breast milk that could be responsible for the observed cognitive differences is insulinlike growth factor I, which is contained in higher concentration in breast milk than in formula \[23\] and has been shown to be absorbed intact across the newborn infant's gastrointestinal tract.\[24\]
>
> On the other hand, studies showing long-term epigenetic behavioral effects of licking and grooming by mother rats of their pups \[25\] suggest that the physical and/or emotional act of breastfeeding might also lead to permanent physiologic changes that accelerate neurocognitive development. Finally, it is possible that the increased frequency and duration of maternal-infant contact implicit in breastfeeding vs bottle-feeding could increase verbal interaction between mother and infant, which might also have a stimulatory effect on cognitive development.
>
> \[21\] Simmer K. Longchain polyunsaturated fatty acid supplementation in infants born at term \[update of: Cochrane Database Syst Rev. 2000;(2):CD000376\]. Cochrane Database Syst Rev 2001; (4) CD000376
>
> \[22\] Simmer K, Patole S. Longchain polyunsaturated fatty acid supplementation in preterm infants \[update of: Cochrane Database Syst Rev. 2000;(2):CD000375\]. Cochrane Database Syst Rev 2004; (1) CD000375.
>
> \[23\] Nagashima K, Itoh K, Kuroume T. Levels of insulin-like growth factor I in full- and preterm human milk in comparison to levels in cow's milk and in milk formulas. Biol Neonate 1990;58 (6) 343- 346
>
> \[24\] Philipps AF, Rao R, Anderson GG, McCracken DM, Lake M, Koldovsky O. Fate of insulin-like growth factors I and II administered orogastrically to suckling rats. Pediatr Res 1995;37 (5) 586- 592
>
> \[25\] Weaver IC, Cervoni N, Champagnhttp://ojs.lib.swin.edu.au/index.php/ejap/article/viewFile/71/100..e FA, D'Alessio AC, Sharma S, Seckl JR, Dymov S, Szyf M, Meaney MJ. Epigenetic programming by maternal behavior. Nat Neurosci 2004;7 (8) 847- 854

### References

* Kafetsios, K. (2004). Attachment and emotional intelligence abilities across the life course. Personality and Individual Differences, 37, 129-145.
* Kramer, M.S., Aboud, F., Mironova, E., Vanilovich, I., Platt, R.W., Matush, L., Igumnov, S., Fombonne, E., Bogdanovich, N., Ducruet, T. & others (2008). Breastfeeding and child cognitive development: new evidence from a large randomized trial. Archives of General Psychiatry, 65, 578.
* Parker, J.D.A., Creque, R.E., Barnhart, D.L., Harris, J.I., Majeski, S.A., Wood, L.M., Bond, B.J. & Hogan, M.J. (2004). Academic achievement in high school: does emotional intelligence matter?. Personality and Individual Differences, 37, 1321-1330. PDF
* Sillick, T.J. & Schutte, N.S. (2006). Emotional intelligence and self-esteem mediate between perceived early parental love and adult happiness. E-Journal of Applied Psychology, 2. PDF

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Tags: intelligence, developmental-psychology, parenting
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# Question
Title: Does typical duration of Short Term Memory differ between tasks?
The duration of Short Term Memory is a fuzzy thing; Wikipedia notes several disputes over it's length and I recently alluded to this fuzziness myself.

However, I wonder if part of the apparently unpredictable duration is to do with the different types of details we remember. For instance I find it very likely that context-rich information such as where I left my car keys (many related cues exist in the relevant location to make it recognizable) likely persists longer than fairly arbitrary data (no relevant cues typically exist, except perhaps area code).

Experiments typically only focus on a single task or related tasks to measure short term memory. Is there any evidence that indicates different short term memory tasks have different "forgetting functions" or time until a specific percentage of the information is lost?

Tasks I'm thinking of are basic memory tests like remembering lists of words/numbers/letters, remembering parts of a story, answers to a quiz; ideally things with different sorts of modality or potential for Chunking.

# Answer
> 3 votes
As you pointed out, the duration of short term memory(STM) varies and there are different theories. However, in mainstream opinion, ideas or thoughts classified as "short term" are said to decay after a short amount of time (minutes at most). If an idea is recallable after a few minutes (or even a minute) then it would be classified under "long term memory" (LTM). Your example of leaving your keys and then later remembering would be the following process: You leave your keys and the act is stored in your working memory and through special attention is encoded into LTM which you later recall while looking for your keys. Further, if you are using "retrieval cues" then you are attempting to "retrieve" it from your encoded LTM. So if a cue reminds you of something then that "thing" was already encoded in LTM. So this "keys" example and examples involving "remembering lists of words/numbers/letters, remembering parts of a story, answers to a quiz" are not short term memory issues at all but rather encoding and LTM issues.

So if your question is "Does the chance of encoding from STM to LTM differ between tasks?" the answer is yes.

You do have a greater likelihood of encoding certain short term memories over others. This is generally because you have a vested interest in an idea or it has an attribute that is distinct from the others. For example: if I listed "apple, banana, orange, house, kiwi, mango" then you may pay special attention to "house" because it is not a fruit and thus different. Because you pay more attention to this it has a greater chance of being remembered. Interest also plays a part. If you obsessed over something (let's say ponies) and that word or an associated word (e.g. pony) appeared in a random list then you are more likely to remember that word than the other, less significant, words. It has also been shown that on average people remember the first word in a list (primacy) and the last word in a list (proximity) than any given word in the middle. Lastly, of course, there is a greater liklihood of remembering something if you try through mnemonics such as you mentioned (rehearsal and chunking). I hope this answered your question. I also hope I didn't misunderstand your question.

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Tags: memory, short-term-memory
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# Question
Title: Why do some individuals enjoy watching horror movies?
What is a scientific explanation for why some people enjoy watching horror movies?

# Answer
Certain emotions/situations trigger parts of body's self defense mechanism which in turn make the brain release certain chemical compounds.

These chemical compounds in turn prepares your body to respond to the situation at hand. For example in case of life threatening situation one experiences an adrenaline rush which prepares the body by quickening the heart rate and adding strength (sometimes perceived as almost superhuman) and speed to our usual abilities. This lets an individual fight to the best of his ability or run away as quickly as possible.

As a side effect of adrenaline, the body releases dopamine which (among its many uses) stimulates the brain's pleasure system.

Thus when you experience a 'fear' moment in a horror movie, your brain perceives it as a threat and triggers and adrenaline rush which in turn releases dopamine.

Further reading: Adrenaline rush, Dopamine functions
> 6 votes

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Tags: emotion, physiology
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# Question
Title: What tasks does Bayesian decision-making model poorly?
Bayesianism has been a relatively successful paradigm for modeling decision-making. However, not every psychologist is a bayesian, and there are tasks such as the Tversky & Shafir (1992) experiments that are hard to reconcile with the bayesian approach.

**Is there a list (or suvery-paper) of decision-making experiments that are hard to account for with the probabilistic approach?** What are these experiments? What are some of their common features?

---

### References and related questions

# Answer
> 16 votes
There is currently a lot of debate surrounding what questions Bayesian modeling is appropriate for answering within cognitive science, as well what makes a "poor model." Unfortunately these become extremely thorny issues very quickly, partly because what is called "bayesian modeling" actually refers to a rather heterogeneous set of approaches and philosophies, and partly because different models serve very different purposes, making the definition of a "poor model" very difficult to agree on.

Nonetheless, I can strongly recommend two papers that deal with these issues in depth. The first is Jones & Love's 2011 Behavioral & Brain Sciences paper "Bayesian Fundamentalism or Enlightenment? On the explanatory status and theoretical contributions of Bayesian models of cognition." Fortunately, BBS articles include open peer commentary - so you can see the reaction of the larger field to their claims.

The second paper is Bowers & Davis's 2012 Psychonomic Bulletin & Review article titled "Bayesian just-so stories in psychology and neuroscience." These papers both make very credible arguments that Bayesian models are actually "poor models" even when they would claim to be good; both papers highlight a number of phenomena that are difficult to fit with Bayesian models without resorting to the same kinds of parameter twiddling that Bayesians tend to criticize other modelers for.

Finally, there is a paper that just came out today describing the failure of a Bayesian model to capture some phenomena in the domain of causal reasoning. This has been traditionally understood as a relative strong suit of Bayesian modeling, making the findings of this paper somewhat striking. I have not read it, but it's in press by Bes, Sloman, Lucas & Raufaste at Cognitive Science, titled "Non-Bayesian Inference: Causal Structure Trumps Correlation."

### References

* Bowers, J.S. & Davis, C.J. (2012). Bayesian just-so stories in psychology and neuroscience.. Psychological bulletin, 138, 389.PDF
* Jones, M. & Love, B.C. (2011). Bayesian Fundamentalism or Enlightenment? On the explanatory status and theoretical contributions of Bayesian models of cognition. Behavioral and Brain Sciences, 34, 169-188. PDF
* Bes, B., Sloman, S., Lucas, C.G. & Raufaste, E. (2012). Non-Bayesian inference: Causal structure trumps correlation. Cognitive Science. PDF

# Answer
> 10 votes
@CHCH has provided a good broad overview, but I thought I would also append some specific experiments that are considered to be a weakness of Bayesian models. The whole theme of this answer is an extension of Tversky and Kahneman's program of rationality-violation. All of these experiments *can* be fitted by *some* Bayesian-ish just-so model of the sort Bowers & Davis (2012) discuss. These **just-so models** usually requires an unreasonably large state space (lots of free parameters), or grafting on unnatural heuristic-and-biases mechanisms for each individual experiment without any guidance from Bayesianism. I will present my narrative as an annotated bibliography.

> Shafir, E. & Tversky, A. (1992) Thinking through uncertainty: nonconsequential reasoning and choice. *Cognitive Psychology* 24: 449-474.
>
> Townsend, J.T., Silva, K.M., Spencer-Smith, J., & Wenger, M. (2000) Exploring the relations between categorization and decision making with regard to realistic face stimuli. *Pragmatics and Cognition* 8: 83-105.
>
> Tversky, A., & Shafir, E. (1992) The disjunction effect in choice under uncertainty. *Psychological Science* 3: 305-309.

As mentioned in the question, and elsewhere on the site, **violation of the sure-thing principle** is one of the most popular examples of departures from Bayesianism. Given a random variable that can have only two possible outcomes A and B, probability requires $p(X)$ to be between $p(X|A)$ and $p(X|B)$. A violation is when $p(X) \> p(X|A)$ *and* $p(X) \> p(X|B)$ (or both $\<$ instead). ST showed the violation in a game-theoretic setting, TS in a two-stage gambling task, and TSS-SW in a face-categorization task.

> Tversky, A., & Kahneman, D. (1983). Extensional versus intuitive reasoning: the conjuctive fallacy in probability judgement. *Psychology Review* 101: 547-567.

In this study, TK described Linda and then asked the participant to make a probability judgement $p(\text{BT})$ of Linda being a bank-teller, or a probability judgement $p(\text{BT} \\;\\&\\; \text{F})$ of Linda being a bank-teller *and* a feminist. In any Bayesian model (without some grafted mechanisms or weird latent variables) you need to have $p(\text{BT}) \geq p(\text{BT} \\;\\&\\; \text{F})$, but the participants judged $p(\text{BT}) \< p(\text{BT} \\;\\&\\; \text{F})$ and committed a **conjunction fallacy**.

> Gavanski, I., & Roskos-Ewoldsen, D.R. (1991) Representativeness and conjoint probability. *Journal of Personality and Social Psychology* 61(2): 181-194.

TK's ad-hoc explanation for this is the *representative heuristic*. GR-E recreate the fallacy in a setting where they show that the **ad-hoc heuristic is not sufficient**. This points out the weakness of ad-hoc fixes to Bayesian-ish approaches.

> Sides, A., Osherson, D., Bonini, N., and Viale, R. (2002) On the reality of the conjunction fallacy. *Memory & Cognition* 30(2): 191-198.

It is natural to suspect that TK's result could be an artifact of participants not understanding the modern concept of probability. SOBV account for this by using a betting paradigm that uses probabilities implicitly instead of asking participants to report numeric values. SOBV show that the conjunction fallacy is **independent of numeric probability reporting** and thus an intrinsic 'error'.

> Feldman, J.M. & Lynch, J.G. (1988) Self-generated validity and other effects of measurement on belief, attitude, intention, and behavior. *Journal of Applied Psychology* 73: 421-435.
>
> Moore, D.W. (2002) Measuring new types of question-order effects. *Public Opinion Quarterly* 66: 80-91
>
> Schuman, H., & Presser, S. (1981) Questions and answers in attitude surveys: experiments on question form, wording, and content

When conducting a questionnaire, the order questions are asked in changes the resulting probability judgements. For a purely Bayesian approach, the mutual probability of asking A then B and getting a specific outcome is $p(A)p(B|A) = p(A \\& B) = p(B \\& A) = p(B)p(A|B)$. This would suggest that the order questions are asked shouldn't matter, so we have a **failure of commutativity**.

> Hogarth, R.M. & Einhorn, H.J. (1992) Order effects in belief updating: the belief-adjustment model. *Cognitive Psycholog* 24: 1-55.
>
> Shanteau, J.C. (1970) An additivity model for sequential decision making. *Journal of Experimental Psychology*. 85: 181-191.

The **order effect** is not confined to questions, but also to integrating evidence. The strongest point of Bayesianism is a clear theory of how to update hypotheses, given evidence. Unfortunately, for Bayes' rule $p(H|A \\& B) = p(H|B \\& A)$, but HE & S show that for humans this is not always the case and present heuristic-and-biases alternatives.

> Berges, G.R., Chapman, G.B., Levy, B.T., Ely, J.W., & Oppliger, R.A. (1998) Clinical diagnosis and order information. *Medical Decision Making* 18: 412-417.
>
> McKenzie, C.R.M., Lee, S.M., & Chen, K.K. (2002) When negative evidence increases confidence: change in belief after hearing two sides of a dispute. *Journal of Behavioral Decision Making* 15: 1-18.

It might be tempting to suspect that these order effects are confined to artificial laboratory settings. Unfortunately, they **appear in natural settings** associated with rational decision making such as BCLEO's study of medical diagnosis and MLC's of dispute mediation in a jury.

> Aerts, D. & Sozzo, S. (2011) Quantum Structure in Cognition: Why and How Concepts Are Entangled. *Quantum Interaction* 7052: 116-127.

AS studied membership judgements for pairs of **concept combinations**, and found among their participants found forms of dependence between concept pairs that violated Bell's theorem and thus could not be fit by any reasonable classical joint distribution over the concept combinations.

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Tags: reference-request, decision-making, experimental-psychology, rationality, bayesian
---


# Question
Title: What happens when a person "imagines" how food could taste like just from looking at it?
What processes are triggered by imagining the taste of food (let's assume it's sealed so that its smell doesn't reach the test subject's nose) only by looking at it, based on memories of food with similar color, shape, texture and size?

If the food seems to be good, usually saliva is generated, but what other things happen?

# Answer
> 8 votes
As Josh Gitlin said, imagining something activates more or less the same parts of the brain as actually experiencing it. Behrmann (2000) is a good introduction to this in the visual domain, though that article is a bit outdated now. There is also a lot of evidence that representations of meanings (semantic memory) involve a distributed network of perceptual regions (e.g., Binder & Desai, 2011; also Barsalou, 2008) and there are some computational models that try to capture this (e.g., Rogers et al., 2004). Putting this evidence together suggests that the sight of food (visual input) would spread activation through the semantic network and would activate the other perceptual, emotional, and linguistic associations (taste, smell, food-related memories, etc.). Salivation is one possible outcome of the activation of taste and smell representations; but I think it is also reasonable to expect activation of memories of eating related foods, etc.

Dana Small is one person who has done some very interesting studies on the neuroscience of taste and smell perception, including top-down effects like anticipation (e.g., Small et al., 2008).

References

Barsalou, L. W. (2008). Grounded cognition. *Annual Review of Psychology*, 59, 617–645.

Behrmann, M. (2000). The mind’s eye mapped onto the brain's matter. *Current Directions in Psychological Science*, 9(2), 50–54.

Binder, J. R., & Desai, R. H. (2011). The neurobiology of semantic memory. *Trends in Cognitive Sciences*, 15(11), 527–536. doi:10.1016/j.tics.2011.10.001

Rogers, T. T., Lambon Ralph, M. A., Garrard, P., Bozeat, S., McClelland, J. L., Hodges, J. R., & Patterson, K. E. (2004). Structure and Deterioration of Semantic Memory: A Neuropsychological and Computational Investigation. *Psychological Review*, 111(1), 205–235.

Small, D. M., Veldhuizen, M. G., Felsted, J., Mak, Y. E., & McGlone, F. (2008). Separable Substrates for Anticipatory and Consummatory Food Chemosensation. *Neuron*, 57(5), 786–797. http://dx.doi.org/10.1016/j.neuron.2008.01.021

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Tags: cognitive-psychology, perception, feeding
---


# Question
Title: Why do humans prefer symmetrical arrangement of objects?
Most of the times, we associate symmetry with beauty. The symmetry may be in architectural/interior design for instance. Why would this be so ?

# Answer
### Indicator of genetic fitness argument

*There is an evolutionary psychology argument. As with most evolutionary psychology arguments, the strength of the evidence is typically a bit fuzzy.*

Symmetry in many aspects of the human body is functional. Such symmetry might be seen as the natural state that arises from a healthy life and a youthful body. In contrast various genetic abnormalities, diseases, and the like can give rise to asymmetry (e.g., scars, moles, freckles, ageing processes, deformities, etc.).

The argument might continue that it is adaptive for us to seek out sexual partners who appear genetically and environmentally fit where symmetry may be one indication of this fitness. One could even extend the evolutionary argument to suggest that it would be adaptive to avoid certain types of diseased individuals in order to reduce the risk of catching some disease, where various forms of asymmetry may be indicative of this.

How does this explain our desire for symmetry in physical objects? The perception of beauty in the environment might be seen as an extension of perceptions of beauty in other people.

Little and Jones also summarise this perspective

> One explanation for the preference for symmetrical faces comes from a postulated link to an evolutionary adaptation to identify high-quality mates (see Thornhill & Gangestad (1999) for review). Symmetry in human faces has been linked to potential heritable fitness (‘goodgenes’) because symmetry is a useful measure of the ability of an organism to cope with developmental stress (both genetic and environmental). As the optimal developmental outcome of most characters is symmetry, deviation from perfect symmetry can be considered a reflection of challenges to development. Only high-quality individuals can maintain symmetrical development under environmental and genetic stress and therefore symmetry can serve as an indicator of phenotypic quality as well as genotypic quality (e.g. the ability to resist disease: see Møller (1997) and Møller & Thornhill (1998) for reviews). This logic would lead to a preference for high symmetry mates as evolution will have favoured individuals who had preferences for high-quality mates over low-quality mates. Indeed, morphological symmetry appears to be related to reproductive success in many species, including humans (Gangestad & Thornhill 1997a; Møller & Thornhill 1998). For example, more symmetrical human males have more sexual partners than less symmetrical men (Thornhill & Gangestad 1994) and symmetrical males are also more likely to be chosen as extra-pair partners (Gangestad & Thornhill 1997b). Thus the link between symmetry and attractiveness may reflect that preferences for symmetrical individuals may be potentially adaptive.

### Perceptual argument

Enquist and Arak (1994) articulate a perceptual clarity argument. They wrote (my bolding):

> Humans and certain other species find symmetrical patterns more attractive than asymmetrical ones. These preferences may appear in response to biological signals1–3, or in situations where there is no obvious signalling context, such as exploratory behaviour4,5 and human aesthetic response to pattern6–8. It has been proposed9,10 that **preferences for symmetry have evolved in animals because the degree of symmetry in signals indicates the signaller's quality**. By contrast, we show here that **symmetry preferences may arise as a by-product of the need to recognize objects irrespective of their position and orientation in the visual field**. The existence of sensory biases for symmetry may have been exploited independently by natural selection acting on biological signals and by human artistic innovation. This may account for the observed convergence on symmetrical forms in nature and decorative art.

### References

* Enquist, M., Arak, A. & others (1994). Symmetry, beauty and evolution. Nature, 372, 169-172.
* Little, A.C. & Jones, B.C. (2003). Evidence against perceptual bias views for symmetry preferences in human faces. Proceedings of the Royal Society of London. Series B: Biological Sciences, 270, 1759-1763. PDF
> 14 votes

# Answer
There is a processing fluency theory that explains it quite nicely. In short, according to this theory the symmetrical objects are pleasant as they are easier to process.

See Reber et al (2004) for a detailed description:

> We propose that aesthetic pleasure is a function of the perceiver's processing dynamics: The more fluently perceivers can process an object, the more positive their aesthetic response. We review variables known to influence aesthetic judgments, such as figural goodness, figure-ground contrast, stimulus repetition, symmetry, and prototypicality, and trace their effects to changes in processing fluency. Other variables that influence processing fluency, like visual or semantic priming, similarly increase judgments of aesthetic pleasure. Our proposal provides an integrative framework for the study of aesthetic pleasure and sheds light on the interplay between early preferences versus cultural infiuences on taste, preferences for both prototypical and abstracted forms, and the relation between beauty and truth. In contrast to theories that trace aesthetic pleasure to objective stimulus features per se, we propose that beauty is grounded in the processing experiences of the perceiver, which are in part a function of stimulus properties.

### References

* Reber, R., Schwarz, N., & Winkielman, P. (2004). Processing fluency and aesthetic pleasure: is beauty in the perceiver’s processing experience? Personality and Social Psychology Review, 8(4), 364–382. doi:10.1207/s15327957pspr0804\_3 PDF
> 7 votes

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Tags: perception, evolution, aesthetics
---


# Question
Title: Is there a correlation between EQ (EI) and IQ?
Is there a correlation, positive or negative, between *emotional intelligence* and *IQ*?

# Answer
> 14 votes
My understanding is that self-report measures of emotional intelligence tend to have very weak correlations with traditional measures of cognitive ability, and ability-based measures of emotional intelligence have low to moderate correlations with traditional measures of cognitive ability. The following provides relevant extracts from Conte (2005) that directly relates to these points. For a more complete picture you may wish to read the article.

### Self-report measures of emotional intelligence

> The EQ-i is a 133-item self-report measure that takes approximately 30 minutes to complete (Bar-On, 2000) ... With respect to discriminant validity, the EQ-i correlated 0.12 with the Wechsler Adult Intelligence Scale (Bar-On, 2000), and the average correlation between the EQ-i and the Big Five personality measures was approximately 0.50 (Dawda & Hart, 2000)

### Ability based measures of emotional intelligence

The MEIS and MSCEIT are both ability based measures of emotional intelligence.

> Data from several studies indicate that the MEIS correlates between 0.30 and 0.40 with traditional measures of cognitive ability (Roberts et al., 2001; Van Rooy & Viswesvaran, 2004)

### Relation between ability and personality based measures

It also appears that self-report and ability based measures of emotional intelligence are measuring relatively distinct variables.

> Mayer et al. (2000) found that the MSCEIT and Bar-On scales correlated 0.36, indicating that they share approximately 13 percent of their variance. In a more recent study, Brackett and Mayer (2003) found that the MSCEIT and Bar-On scales correlated 0.21, indicating that they share approximately 4 percent of their variance.

### References

* Bar-On, R. (2000). Emotional and Social Intelligence: Insights from the Emotional Quotient Inventory. In Bar-On, R.; Parker, J. (eds.). *The handbook of emotional intelligence: Theory, development, assessment, and application at home, school, and in the workplace* (pp. 363–388). Jossey-Bass. ISBN 978-0-470-90743-6
* Brackett, M. A., & Mayer, J. D. (2003). Convergent, discriminant, and incremental validity of competing measures of emotional intelligence. *Personality and Social Psychology Bulletin*, 29(9), 1147–1158. doi:10.1177/0146167203254596
* Conte, J.M. (2005). A review and critique of emotional intelligence measures. *Journal of Organizational Behavior*, 26(4), 433–440. doi:10.1002/job.319. \[PDF\]
* Dawda, D., & Hart, S. D. (2000). Assessing emotional intelligence: reliability and validity of the Bar-On Emotional Quotient Inventory (EQ-i) in university students. *Personality and Individual Differences*, 28(4), 797–812. doi:10.1016/S0191-8869(99)00139-7
* Mayer, J. D., Caruso, D., & Salovey, P. (2000). Selecting a measure of emotional intelligence: the case for ability scales. In Bar-On, R.; Parker, J. (eds.). *The handbook of emotional intelligence: Theory, development, assessment, and application at home, school, and in the workplace* (pp. 320–342). Jossey-Bass. ISBN 978-0-470-90743-6
* Roberts, R. D., Zeidner, M., & Matthews, G. (2001). Does emotional intelligence meet traditional standards for an intelligence? Some new data and conclusions. *Emotion*, 1(3), 196–231. doi:10.1037/1528-3542.1.3.196
* Van Rooy, D. L., & Viswesvaran, C. (2004). Emotional intelligence: a meta-analytic investigation of predictive validity and nomological net. *Journal of Vocational Behavior*, 65(1), 71–95. doi:10.1016/S0001-8791(03)00076-9

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Tags: intelligence, emotion
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title: How do we get used to smells?

text:
# Question
Title: How do we get used to smells?
How do we get used to smells?

For example, you walk into a room with a certain stench, but it seems no matter how strong it may be, spending enough time in the room will allow you to stop smelling it.

What's going on here?

# Answer
> 12 votes
As Ben Brocka mentioned, what you're describing is **Habituation**, which Wikipedia defines as:

> Habituation is a decrease in an elicited behavior resulting from the repeated presentation of an eliciting stimulus (a simple form of learning.

More specifically, it's technically called Neural adaptation. To quote Wikipedia again:

> Neural adaptation or sensory adaptation is a change over time in the responsiveness of the sensory system to a constant stimulus. It is usually experienced as a change in the stimulus. For example, if one rests one's hand on a table, one immediately feels the table's surface on one's skin. Within a few seconds, however, one ceases to feel the table's surface. The sensory neurons stimulated by the table's surface respond immediately, but then respond less and less until they may not respond at all; this is neural adaptation

As this was explained to me in Psychology 101, this is the same phenomenon which allows us to not feel our shoes shortly after putting them on. It's also what enables people to perform really dirty, smelly jobs like sewer maintenance and garbage collection.

The process works exactly as you described, and many people can instantly relate to it: The longer you are exposed to a given *stimulus* (like a smell) the less you continue to react to the stimulus. The stimulus becomes more "normal" to you, and you start to think of it less. As soon as the stimulus is removed, the effect begins to reverse. The Characteristics of Habituation section of the Wikipedia article covers this.

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Tags: neuroscience, perception, sensation
---


# Question
Title: Is there a reasonably valid and reliable self-measure of computer literacy?
Measuring computer literacy or skill is important when grouping respondents for usability studies and other Human Computer Interaction studies. But for the life of me I can't find a good, simple but reliable measure of it.

The most frequent suggestion I see is a terribly complicated and non-standard approach like comparing multiple Likert scales for things like "I feel comfortable with computers". I'm fine with multiple Likert scales if it's a *proven* measure, but hundreds of people making up their own multi-question Likert scales does *not* create reproducible research.

I'm a proponent of just asking the darn question as I find it less ridiculous than made up scales, but I'm sure HCI work has been done on this.

Is there an agreed upon or otherwise well tested, reliable and valid self-measure of computer literacy? Ideally one which could be used to easily group participants into relative groups of proficiency, such as a Likert scale. By "self-measure" I mean some test item that can be asked on a survey rather than any form of observation.

# Answer
> 8 votes
*I don't know of any well-validated general short scales. Here are a few thoughts:*

* A major distinction is between **self-report versus ability** based measures. Self-report measures will ask the participant to rate their knowledge, skills, and experience. Ability based measures will require demonstration of competence. If you are limited to "self-measures", ability based measures are still possible (e.g., set of multiple choice, or possibly short answer questions). An issue with self-report measures is that people may be inaccurate in their own self-evaluation. Ability-based measures do not have this issue.
* Having **more items generally increases the reliability** of the test. It also permits you to assess statistically the item properties of the scale.
* **Computer literacy is a broad construct**. The meaning and standards of computer literacy are probably also changing over time, as computing practices change and as the computers get further integrated into society. I assume this is part of the reason why a lot of people use customised instruments. For example, I once did a study of keyboard-based text-editing. To assess prior experience, I asked a number of general questions about computing experience, but I also assessed various specific measures related to knowledge of shortcut keys.

A quick search revealed a couple of scales (e.g., Wilkinson et al, 2010, Fogarty et al, 2001). None look like entirely what you are after, but I thought I'd mention them. Both followed a formal scale development process.

### Wilkinson et al

For example, here's a subset of the items from Wilkinson et al

```
ICT skills
I know how to create a folder
I feel confident closing down a software program
I do not feel confident attaching a file to an email
I can use a word processing application
I know how to save a document to a folder
I would not recognise a PDF (Portable Document File)
I would have difficulty finding a web site∗
I feel confident making selections from popup menus∗
I would find it difficult to search a database of references to journal papers
I need help with using computers for learninga
I feel confident using a computer to write a letter or essay
I do not know how to find an article in an e-journal

Experience with computers
I have used computers at work/school∗
I feel disadvantaged by my lack of experience with computers
I communicate with people using email
I have used computers to look for information for example: Library catalogue/books
I have used computers to support my learning
I have used computers to find out about careers
I have used computers for leisure

```

### Fogarty et al

Here's a subset of the items from Fogarty et al

```
The following statements refer to your confidence when using computers.
1. I have less trouble learning how to use a computer than I do learning other things.
2. When I have difficulties using a computer I know I can handle them.
3. I am not what I would call a computer person.
4. It takes me much longer to understand how to use computers than the average person.
5. I have never felt myself able to learn how to use computers.
6. I enjoy trying  new things on a computer.
7. I find having to use computers frightening.
8. I find many aspects of using computers interesting and challenging.
9. I don’t understand how some people can seem to enjoy spending so much time using
computers.
10. I have never been very excited about using computers.
11. I find using computers confusing.
12. I’m nervous that I’m not good enough with computers to be able to use them to learn
mathematics.

```

### References

* Wilkinson, A., Roberts, J. & While, A.E. (2010). Construction of an instrument to measure student information and communication technology skills, experience and attitudes to e-learning. Computers in Human Behavior, 26, 1369-1376.
* Fogarty, G., Cretchley, P., Harman, C., Ellerton, N. & Konki, N. (2001). Validation of a questionnaire to measure mathematics confidence, computer confidence, and attitudes towards the use of technology for learning mathematics. Mathematics Education Research Journal, 13, 154-160. PDF

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Tags: measurement, methodology, hci
---


# Question
Title: What term describes the discrepancy in reported intention to vote and actual voting behaviour?
I am interested in prediction markets, where traders have a monetary incentive to bet on who they think would win in an election. I think that the financial incentive in prediction markets makes them a better predictor of future election outcomes than polls.

I think that when people are asked how they would vote on the presidency if tomorrow were the election day, they tend to give you an answer which they would like to see happen rather than how they would actually vote. This discrepancy reduces the predictive value of polls. Alternatively, I think that if the incentives are set correctly the same people tell you more of the truth instead of their wishful thinking. I would call this phenomena "polls bias".

### Questions:

* **What is a scientific term for this problem?**
* **Where can I read further about the phenomena?**

# Answer
It is the social desirability bias.

This is one of the reasons a behavioral study may give better results than a self-report study.
> 2 votes

# Answer
There are many reasons why stated intention can differ from behaviour (e.g., see Theory of Planned Behaviour). Social desirability is one possibility. However, there are many other factors. A person may not know who they are going to vote for or may not have decided. Factors may arise between the point in time when asked and when voting occurs that change the person's voting plan.

Furthermore, there are many potential limitations to polls that can lead their estimates of population voting intention to be inaccurate, and even biased. There is basic sampling error that arises whenever you estimate a population property from a finite sample. There are also a wide range of issues related to getting a sample representative of the voting population (see sampling bias).

Furthermore, polls form part of the information available in betting markets. Thus, in betting markets, people are able to use an ensemble of information including multiple polls, various historical trends regarding how polls change over time, various adjustment to poll predictions that might remove perceived biases and so on.
> 3 votes

---
Tags: reference-request, terminology, bias, political-psychology
---


# Question
Title: What is the threshold where actions are perceived as "instant"?
In Human Computer Interaction and User Experience there's some oft repeated rules of performance:

> * **0.1 second is about the limit for having the user feel that the system is reacting instantaneously, meaning that no special feedback is necessary except to display the result.**
> * 1.0 second is about the limit for the user's flow of thought to stay uninterrupted, even though the user will notice the delay....
> * 10 seconds is about the limit for keeping the user's attention focused on the dialogue...

I'm most interested in this "instantaneous" response. Related is this User Experience Question. A related answer does bring up some sources:

> Card, S. K., Robertson, G. G., and Mackinlay, J. D. (1991). The information visualizer: An information workspace. Proc. ACM CHI'91 Conf. (New Orleans, LA, 28 April-2 May), 181-188.
>
> Miller, R. B. (1968). Response time in man-computer conversational transactions. Proc. AFIPS Fall Joint Computer Conference Vol. 33, 267-277.
>
> Myers, B. A. (1985). The importance of percent-done progress indicators for computer-human interfaces. Proc. ACM CHI'85 Conf. (San Francisco, CA, 14-18 April), 11-17.

However I can't access any copies of those articles. Also, frankly, they're all *conference papers*. Big HCI research often debuts at conferences, but ideally I'd like something robust which has been tested rather than something written 20-40 years ago for a conference.

One thing I've noticed is the "instant response" threshold quoted tends to be around 100ms to 200ms. Typical human reaction time is about 200ms so I'm wondering if there is a relation there. It seems possible; if something happens so quickly you can't *react* to it, it is practically "instant" in a way.

**Approximately what length of time between action and reaction is perceived as instant by humans?**

# Answer
### Preface

This is a very interesting question, that is also somewhat related to my area of research. I know of several related results (which I might add later in an edit), and I thought that with a few minutes of scholar search I'll find a paper dealing with this question exactly. I was surprised to find no such papers. So I decided to conduct an experiment...

## Answer (preliminary. hopefully, will be edited)

As with many cases in psychology, the **threshold** is completely non-existant: there is no delay up to which the reaction is perceived as instantaneous, and after which it is perceived as delayed. You can measure the probability of the subject perceiving a delay, as a function of the delay time. You can choose any probability you want, arbitrarily, and call it the 'threshold'. If we decide on 50% (the chance of responding there was a delay is identical to the chance of responding it was instantaneous) then for me it is about **110ms**.

The results presented here are based on 100 trials, performed by myself. Hardly counts as good study, but if a few more people run the test, I promise to process the results and post them here (and who knows, maybe even publish it somewhere :))

## To participate in the experiment yourself

* Sign up to ofri.webfactional.com. (It is a site I developed for web-based experiments conducted in my lab. It's still in beta, which is why its under a domain with my name, and not under huji.ac.il. I promise we do not use your email for anything except for identifying you. No spam ever).
* In the **Group Name** field in the registration, enter **instant**.
* Login, and follow the on-screen instructions. Its really simple.
* After running more than 60 trials another button will appear with the text 'show results'. Clicking it will draw a graph similar to the one presented here, based on your personal results.
> 15 votes

# Answer
Interesting question. One (theoretical) answer would be: instantaneous is when people cannot percieve a delay, so the threshold would be the "speed" of perception. But subjectively people might consider something instantaneous, even if they can slowly see it coming, because from their understanding it is "amazing quick" compared to other experiences (for example the media wrote about "instant page load" when DSL was introduced and began to replace dial-in modems). So the question is what exactly you want: do you want subjective user experience, or a physiological limit?

If you look for the physiological limit, look for articles by Rolf Ulrich from Tübingen, Germany, who (among other things) researches how well humans can discern visual or auditory stimuli that are given quickly one after another. His articles give the times. Here is his web page with a list of publications: http://www.uni-tuebingen.de/en/faculties/faculty-of-science/departments/psychologie/research-groups/cognition-and-perception/research-group/rolf-ulrich/publikationen.html (some of them can be downloaded as PDFs from that page).
> 2 votes

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Tags: perception, measurement, time, hci
---


title: What causes laughter?

text:
# Question
Title: What causes laughter?
I was looking at this video from VSauce: "Why did the chicken cross the road?", where several facts about this old joke are exposed and explained.

At some point, (6:59) Michael explains that there is a theory, based on the paper *Computer Model of a "Sense of Humour"* by I. M. Suslov, that says that laughter is the result of the released energy on the pre-judgement one makes about the result of the joke.

Still, this theory does not account for factors like being under the influence of drugs (on which it is generally easier to laugh at things), situations like tickling or other forced laughters like laughter gas itself.

So, which is the currently, widely accepted theory that explains what causes laughter?

# Answer
> 8 votes
The majority of researchers believe it has to do with relief to the flight or fight system and related to human bonding.

For example, we hear the phrase "laughter is contagious". That's because we want to let others know we have good feelings towards them and would like to connect at some level but in a quick and non-direct way.

However, for situations where the joke may be "dangerous", Suslov's theory is better understood. I have also personally witnessed it many times. This kind of laughter follows the familiar model: "Oh no, I hope he doesn't say something that pokes fun or embarrasses me in this social setting". Next, you hear the joke and realizing it doesn't embarrass you (too much) the relief and release of energy transmutes into a laugh.

Also see: http://en.wikipedia.org/wiki/Laughter#Causes

Reference: How Laughter Works:
http://science.howstuffworks.com/environmental/life/inside-the-mind/emotions/laughter.htm

---
Tags: neuroscience, emotion, humour
---


# Question
Title: Is sub-vocalization when reading and writing merely a symptom of lack of fluency?
In reading & writing, I for one, find myself subvocalizing the statement to myself. This behaviour is language-independent. However, the effort and subvocalization involved is greater in any language that I do not use regularly.

**Is sub-vocalization when reading and writing merely a symptom of lack of fluency in a language?**

# Answer
> 5 votes
My understanding was that at least some sub-vocalisation is a normal part of reading and writing. The wikipedia article on subvocalisation cites several sources supporting that claim. The article also claims that there is no evidence to suggest that speed reading training that involves suppression of sub-vocalisation is effective. There is also evidence that suppressing subvocalisation can in some instances result in decrements in performance (see Baddeley et al, 1981).

There is some evidence to suggest that degree of subvocalisation is related to complexity of the reading passage. Baddeley et al 1981 summarise the use of

> the electromyographic monitoring of the muscles involved in vocalisation in order to study the role of articulation in reading (e.g. Sokolov, 1966). Using this technique, Hardyk and Petrinovitch (1970) concluded that subjects were able to read and comprehend simple prose without the occurrence of electromyographic activity, but that such activity did occur in the case of more complex passages.

One explanation would be that degree, prominence or frequency of subvocalisation increases as the reading task gets more difficult, where experienced difficulty would vary both based on the individual's ability with the language and with the objective difficulty of the reading passage.

### References

* Baddeley, A., Marge Eldridge & Vivien Lewis (1981): The role of subvocalisation in reading, The Quarterly Journal of Experimental Psychology Section A: Human Experimental Psychology, 33:4, 439-454
* HARDYK, C. D. and PETRINOVITCH, L. R. (1970). Subvocal speech and comprehension level as a function of the difficulty level of reading material. Journal of Verbal Learning and Verbal Behavior, 9, 647-52.
* SOKOLOV, A. (1966). La parole intbrieure dans la pensbe concrete. In Recherches Psychologiques en U.R.S.S., les Editions du Progrks, U.R.S.S.

# Answer
> 1 votes
Children learn to read and write, by relating the written letters to the spoken word they already know. Due to the primacy of spoken language (in the cognitive development of the average healthy human being), the sounds of words are connected more strongly and more directly to their meaning, than their orthography is. Now, When you see a written word, the sound is (a) activated simply through the connection to the meaning and (b) because it is part of the connection of the orthography to the meaning.

Even if you don't subvocalize by suppresing it, you will always "hear" the sound of the word that you read (mental subvocalization). No hearing person can turn this off. Supressing subvocalization is simply an effort to hold still, and it uses energy and tires your mind.

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Tags: language, reading
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# Question
Title: Why is white on black considered higher contrast than black on white?
While researching to answer Why are "Inverted Colors" considered an accessibility feature? I noticed the puzzling claim that "White text on a black background is a higher contrast to the opposite, so the letterforms need to be wider apart, lighter in weight and have more space between the lines." It's repeated a lot, particularly by design folks, but I couldn't find psychological research to support (or refute) it.

In terms of actual contrast ratio, inverting a black on white scheme won't change the contrast at all; the colors themselves are just as distant. Yet I see many claims that "inverted colors" is high contrast. The only real difference between the two I can think of is that the white background of black on white produces considerably more light than a black background. If this difference is enough to induce some level of ocular adaptation perhaps that could be a cause.

So is there a perceived difference in contrast between black on white vs white on black, assuming the same intensities for black/white? What causes it?

# Answer
> 18 votes
Your question is referring to *display polarity*. A positive polar display consists of dark letters on a light background, a negative polar display consists of light letters on a dark background. Polarity by itself is independent of text-to-background contrast, as you rightly state.

Generally, positive polarity facilitates performance (e.g. Buchner & Baumgartner, 2007). This effect is due to the higher overall display luminance (Buchner, Mayr & Brandt, 2009) possibly leading to a greater constriction of the pupil (Taptagaporn & Saito, 1990, 1993) and thus increasing the depth of field and decreasing spherical abberation.

However, this advantage of positive polar displays does not generalize to readers with visual impairment. People with low vision due to cataract (ocular clouding) perform better with negative polar displays (Legge et al., 1985, Sandberg & Gaudio, 2006). This effect has been discussed to be due to a scattering of light leading to a resulting veiling luminance and reduction in text-to-background contrast (Rubin & Legge, 1989).

**In short**: At the level of the display, a change of polarity has no effect on the text-to-background contrast. If the reader's eyes are cloudy, however, the contrasts at the retinal level is decreased for positive compared to negative polarity. This is why offering negative polarity is considered an accessibility feature.

As to why design folks claim negative polarity to be higher in contrast, I can only speculate on the basis of these findings. I suspect that it has to do with the adaptation of the eye to the lower overall luminance of the display. The intensity of the white letters may be perceived as more intense. Also the wider pupil dilatation would lead to a decreased depth of field. This in turn would require wider spacing and lighter weights of letters to achieve readability comparable to positive polarity. Unfortunately, I don't know any research to substantiate these speculations (which doesn't mean that it does not exist).

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Tags: perception, vision, hci
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# Question
Title: What is the brain power devoted to vision and haptics?
I heard a talk by Vincent Hayward on the sense of touch as a multi-modal system, where he claimed that the brain power devoted to haptics is at least as big as the one devoted to vision. I have found some answers with respect to vision, which claim the percentage to be between 25%-33% of the neo-cortex. The cortical homunculus shows a sensory map of the body, where I guess the eye depicted is more related to the haptic part of the eye region, rather than the vision.

* Can you confirm the percentage for vision?
* What is the percentage for haptics?

Quotable sources would be fantastic of-course, but just a rough number would also do. I am mostly interested in the rough relative relation between the two modalities.

# Answer
> 4 votes
I'd argue that "brain power" is *dangerously* vague. Are you looking at weight, volume, area (including or excluding cortical folding), are you looking at just the cortex, or the whole brain?

At a lower level, are you counting just cell bodies, or do you count the processes that join them; do you just weigh the whole lot and try to figure out "power" that way? Do you count long axons projecting from the peripheral nervous system? Because touch would have a massive edge over vision if you counted the weight of those long, thick, myelinated axons in the spinal column.

None of those straight physical measures will give you an estimate of "power" because power implies other more cognitive factors; speed and capacity notably. Myelination gives speed of response to neurons, as does thickness. But a shorter neuron will be faster (more powerful?) than a longer one, and will also weigh less - clearly weight isn't a good estimator of speed, in fact the further information travels through axons the less "powerful" the whole system will be.

But that's just talking about speed - what about capacity? The overall number of indivudal points of input might relate to capacity, but the brain does plenty of post processing on visual input to allow it to process far more information than the eyes actually give it at any one time. Is capacity related to the number of synapses each neuron makes? This probably has something do to more with "depth" of processing than capacity, as it implies that each percept is sent to more places.

And beyond even speed, depth and capacity, what about learning? Which system has a greater ability to adaptively learn and pass learned information back into the decision making parts of the brain? How do you measure that? By the number of NMDA receptors in each system?

Also, what's this "touch" thing anyway? Are you talking about perception of heat, cold, pain (which sort, a$\delta$, perhaps C fibres)? Are you talking about sensations of pressure, like that felt when pushing a heavy object? Those sort of sensations are related more to proprioception than touch - they are all about sensing the environment's reaction to the body based on stretch receptors in the muscles, this is another type of input that makes up the heterogeneous sense labelled "touch".

Each of these types of pressure, superficial touch, pain, heat and cold have different afferent projections, and each has it's own substrate in the brain, with different architectures, different strengths and weaknesses - there is no straightforward "power" to compare any of those components of touch, much less to compare touch to something as remote as vision. This sort of question and attempts to answer it dangerously obscure the complex science behind both systems, giving a false sense of understanding where most of the above questions are unanswered, and possibly unanswerable.

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Tags: neuroscience, vision, sensation
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# Question
Title: How to measure group differences incorporating reaction time / accuracy trade-off?
In a psychological experiment I am measuring subjects' reaction time as well as their error rate. Now I would like to compare two groups (males & females). There might be a bias in the sense that subjects who respond within a small reaction time might also commit more errors.

* What would be an appropriate way to combine reaction time and error rate to create a measure that takes into consideration this trade-off between "reacting fast" and "reacting correctly".
* E.g., could I just divide reaction time by error rate? Should I center or scale reaction time and error rate before I do this?

# Answer
The basic approach that you are describing sounds like inverse efficiency scores (e.g., see Townsend and Ashby, 1978,1983), which are measured as

$$\frac{r}{1-e} = \frac{r}{c}$$ where $r$ is reaction time, $e$ is proportion error, and $c$ is proportion correct. John Christie provides a critique of inverse efficiency scores here or see the discussion in Bruyer and Brysbaert (2011).

This existing question on "How to analyze reaction times and accuracy together?" hopefully answers your question. The answers there generally advocate more sophisticated approaches for combining reaction time and accuracy such as the Linear Ballistic Accumulator Model and Ratcliff's diffusion model.

### References

* Bruyer, R. & Brysbaert, M. (2011). Combining Speed and Accuracy in Cognitive Psychology: Is the Inverse Efficiency Score (IES) a Better Dependent Variable than the Mean Reaction Time (RT) and the Percentage Of Errors (PE)?. Psychologica Belgica, 51, 5-13. PDF
* Townsend, J.T., & Ashby, F.G. (1978). Methods of modeling capacity in simple processing systems. In J. Castellan & F. Restle (Eds.), Cognitive theory. Vol. 3. (pp. 200-239). Hillsdale, N.J.: Erlbaum.
* Townsend, J.T., & Ashby, F.G. (1983). Stochastic modeling of elementary psychological processes. Cambridge: Cambridge University Press.
> 11 votes

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Tags: measurement, methodology, experimental-psychology, reaction-time
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# Question
Title: How does daily amount of sleep vary within and between healthy adults?
I'm interested in research that has employed the following or similar research design:

* Measure the daily amount of sleep
* every day for an for an extended period (e.g., more than a month)
* in a relatively large sample (e.g., $n \> 100$) of "normal" healthy adults

This would give rise to sleep measurements on multiple days and for multiple individuals. Thus, we could define $y\_{ij}$ as the amount of sleep of person $i$ on day $j$. Descriptive statistics could be calculated on the set of daily sleep measurements of person $i$ such as the mean and standard deviation. These within-person descriptive statistics could also be summarised at the group-level.

### Questions

In general, **what are the main descriptive statistics of such data?**

More specifically, I'd be interested in knowing:

1. What is the mean of the within-person mean of daily amount of sleep?
2. What is the standard deviation of the within-person mean of daily amount of sleep?
3. What is the mean of the within-person standard deviation of daily amount of sleep?
4. What is the standard deviation of the within-persons standard deviation of daily amount of sleep?

Presumably such results are contingent on how sleep is defined and measured, as well as many other factors such as the nature of the target population. Thus, any comments about these factors would also be welcome.

# Answer
*Just a starting point*. Jean-Louis et al (2000) provide one sample of population adult sample using objective sleep measures. To quote the abstract

> Using Actillumes, we investigated whether self-reported sleep durations were indicative of a population decline in sleep duration. We also explored illumination and activity patterns. Methods: San Diego adults (n = 273, age range: 40–64) were recruited through random telephone calls and were monitored at home while engaging in usual daily routines. Results: **Volunteers slept an average of 6.22 hours** and received an average of 554 lux (environmental illumination). The timing of sleep, illumination, and activity occurred at 2:44, 12:57, and 13:43, respectively.

### References

* Jean-Louis, G., Kripke, D.F., Ancoli-Israel, S., Klauber, M.R. & Sepulveda, R.S. (2000). Sleep duration, illumination, and activity patterns in a population sample: effects of gender and ethnicity. Biological psychiatry, 47, 921-927.
> 2 votes

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Tags: sleep
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# Question
Title: Is there a better way to describe brain activity than EEG "brain waves"
I've been reading about EEG brain waves, which are specific waveforms that are observed on the EEG output, and are usually scored by humans. This concept has been around for quite some time.

**Is there anything "newer" or "better" than EEG brainwaves discovered in the recent years?**

Given the rise in commercially available EEG sensors, has any company succeeded at putting forth a way to analyze or quantify the output of these sensors to give some useful information to researchers? I'm thinking of brainwave-processing algorithms. For example in Actigraphy, the study of human motion, there are algorithms like "if 19 out of 20 minutes of activity are scored as sleep, then the sleep onset is known to happen at the start of the 20 minute window". Is there something similar for brainwave or derived metrics?

# Answer
> 15 votes
There is no better way to describe brain activity than brain waves! :)

There are newer ways to analyze and think about brain waves, though. Usually you will find these under literature on neuronal oscillations.

**Good aspects** of thinking about brain activity using brain waves:

* Brain waves are directly related to neural activity. They are an electric or magnetic measure of current passing through neurons. It doesn't get closer than this (unless you use an invasive technique). In comparison, fMRI measures changes in blood flow over one or two seconds after neurons have fired.
* Brain waves are measured essentially at the speed of light, i.e. with no perceptible delay between the onset of neural activity and the moment that the electrode or MEG sensor picks them up. This allows for measuring brain activity as it unfolds, as the brain processes information on the order of milliseconds.

**Bad aspects** include:

* Seriously compromised spatial resolution. With EEG, the electrical signal gets smeared by passing through the skull. With MEG the measure is more direct, but still, all sensors pick up activity in any part of the brain (at least in EEG; I'm not so sure about MEG), so it is very difficult to say with certainty where precisely something is localized. Methods do exist, but (in my experience) it doesn't come close to MRI precision. It also gets very complicated very quickly.
* Activity is picked up only from the neocortex. You can't say much about deep brain activity.
* Brain waves are utterly unintuitive. It is very hard to see how a wavy line on a screen can tell us something about the most interesting thing in the world: ourselves. It is supposed to be related to our consciousness, to our thoughts and feelings, to our personality, state of mind, actions, intentions, everything - yet it's just a wavy line. This is where some hard training in neuroscience comes in.

In the past, brain waves were identified by eyeballing. Nowadays we can do much better. We can imagine that each of these lines is actually composed of many different types of neural activity, happening at different speeds. Neurons firing together quickly will lead to small, brief amplitude changes, whereas neurons firing together at a slower pace will lead to slow waves. The more neurons are firing together, the higher the amplitude of the wave. The faster they are firing together, the lower the wavelength.

The fast and slow wavelengths will be summed up into the single wavy line on the screen, but we can decompose it, e.g. by using a Fourier transform or a wavelet transform. By decomposing, we gain insight into the fact that neurons fire together at different rates when they do different things. For example, if you ignore a visual stimulus, then your visual brain begins to fire at about 10 times per second. This is called the alpha rhythm. If you are actively observing a stimulus, the activity will change to 40-70 times per second. This is the gamma rhythm. Thus, you can say something about what the brain is doing when you see the pattern of neural activity based on a wavy line.

Also, you might notice that two distant parts of the brain have neurons firing together... but that they are in phase with each other. This might mean that they are both processing different aspects of the same information, so it tells us something about functional neuronal connectivity even though we don't see the underlying white matter firing.

In any case, brain waves should not really be seen as better or worse than other measures of neural activity. They simply add their bit of information, that is part the larger puzzle of how the brain works. See here for a really nice comparison of M/EEG with fMRI, and a discussion of all the big issues behind noninvasive electrophysiological measures.

# Answer
> 12 votes
Yes and no. Source estimation has been utilized in electrical engineering for decades, but is becoming more and more prevalent in the EEG realm, especially in light of efforts to register EEG readings with concurrent fMRI studies.

Basically, given a set of EEG (or even MEG, magnetoencephalographic) measurements, can we "invert" them to find the individual current sources that would generate such electrical activity. Forward models in which a set of sources are assumed *a priori* can also be used.

Scholarpedia has an extensive article about these methods. Briefly,

* Parametric dipole modeling
* Spatial scanning and beamforming, one of the more popular being `MUSIC`
* Sourcespace methods, one of the more popular being `sLORETA`

are used, most of which involve some form of matrix transformation of the data into a lower dimensional space and mapping on to a set of point sources.

Current research (e.g., Antelis and Minguez, 2012) uses an approach which brings together the results of multiple dynamic models to improve the estimates.

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References:

Antelis, J.M., Minguez, J.(2012). DYNAMO: Concurrent dynamic multi-model source localization method for EEG and/or MEG. *Journal of Neuroscience Methods*, Available online 26 September 2012 \[DOI\]

# Answer
> 7 votes
I'm surprised that no one has mentioned *spiking* activity. The spatial and temporal resolutions are phenomenal.

The technology to record action potentials simultaneously from many neurons over many cortical areas is growing. Much of theoretical neuroscience deals with how those patterns of spiking convey information.

As with the other answers, I will add to this sketch over the coming days. I wanted to make the point that there are other sources of information about brain activity than EEGs.

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Tags: neuroscience, measurement, neuroimaging, eeg
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# Question
Title: Applications of computational learning theory in the cognitive sciences
Computational learning theory (CoLT) is a branch of theoretical computer science associated with the mathematical analysis of machine learning. A lot of the early ideas of the field take inspiration from human learning. The field has developed into a very rigorous, mathematical, and precise science, but I have not seen it used much in the cognitive sciences directly. There is some indirect use through CoLT's interaction with statistics and machine learning algorithms (say, analyzing neural networks through VC-dimension).

**Are there examples of rigorous uses/applications of CoLT to build theories in psychology, neuroscience, and/or cognitive science?**

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### Notes:

The only two examples I am familiar with are:

1. Gold's theorem on the unlearnability in the limit of certain sets of languages, among them context-free ones.
2. Ronald de Wolf's master's thesis on the impossibility to PAC-learn context-free languages.

The first made quiet a stir in the poverty-of-the-stimulus debate, and the second has been unnoticed by cognitive science.

I am interested in approaches of this flavor. I am relatively comfortable with CoLT as it is studied in mathematics, and am only interested (for this question) in approaches that have direct bearing on theories of human/animal cognition/learning, and not classic machine learning results. I am **looking for general mathematical and asymptotic approaches**, not the running of specific types of algorithms (be it neural-nets, bayesian, or otherwise) to simulate human performance as is typical in computational modeling in cogsci (which I am relatively familiar with).

I am **not interested** in arguments that try to trivially undercut the whole approach, even if they have empirical validity. For instance, the whole approach can be derailed by asserting that human brains are finite and thus asymptotic arguments are useless. This is the same as arguing that all of computational complexity theory is pointless because computers (and the whole universe, for that matter) are finite. It is a valid empirical argument, but boring from the point of view of theory building.

### Related questions:

# Answer
> 4 votes
Related to this is several works on the integration or non-integration of computational models in general to cognitive science. For instance, the Tractable Cognition Thesis basically says that we can improve cognitive modeling if we limit cognitive models to those tractably implementable on a Turing machine.

Van Rooij, I. 2008. The Tractable Cognition Thesis. Cognitive Science 32:939-984. http://staff.science.uva.nl/~szymanik/papers/TractableCognition.pdf

Personally, I disagree with the Tractable Cognition Thesis, and think, similar to Copeland, that a better model would be of an Oracle machine:

Copeland, J. 1998. Turing's O-Machines, Searle, Penrose, and the Brain. Analysis 58(2):128-138.

My own work goes ahead in this regard, and proposes how O-machines can be specifically integrated into cognitive psychology. I give a presentation on it here and the proceedings will be published next year, but message me and I can provide a draft copy if you would like.

http://www.youtube.com/watch?v=chQvZrkznbg&feature=plcp

# Answer
> 2 votes
Recently Bayesian models of cognitive development have been very successful in at least formulating working hypotheses as to how abstract knowledge "regularizes" and guides learning and reasoning from sparse data. I was thinking for instance of the following paper:

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Tags: learning, computational-modeling, mathematical-psychology, theoretical-neuroscience
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# Question
Title: Is there any fMRI evidence for different "states of mind"?
If you've seen a snickers commercial, it goes something like "you are a different person when you are hungry". I'm interested if the person's brain actually looks different when observed through fMRI if the person is tired/hungry, and the person's outlook on the world changes. For example things become more irritating.

**Is there fMRI evidence to support that a person is capable of switching to a different "state of mind" based on the condition of the person's body or neuromodulator levels?**

If there's a better term than "States of mind", could you suggest what it is? I'm thinking of an entrained state which changes the person's outlook on the past, present and the future, as well as influencing the choice of actions and behavior. Is there a good term I can google to find research on this topic?

Thank you for your input!

# Answer
Dario Ringach wrote in a letter titled Neuroscience: States of Mind:

(inline references removed, see link for references)

> **If the ability to perceive oriented stimuli is found to depend on the cortical state, we can then ask a number of important questions about cortical function**. Is the time the cortex spends visiting particular states a function of attention? In other words, if an animal is trained to perceive horizontal stimuli, will there be a corresponding increase in the time the cortex spends sampling the horizontal orientation map relative to the other maps? **Perhaps perceptual learning has more to do with 'top-down' mechanisms (brain processes learning how to 'control' the ongoing state of the early visual cortex) rather than 'bottom-up' mechanisms (external stimuli producing dramatic and long-lasting changes in the way the visual cortex processes incoming information).** In more general terms, one might ask if such intrinsic cortical states represent the brain's 'current hypothesis' about the state of the external world. In this case, the purpose of the cortical machinery would be to continuously update the current hypothesis by considering new visual information.

Rabinovich is well-known in dynamical systems neuroscience for highlighting the importance of **transient states** (as opposed to attractor states). That is, it is the active dynamics that correlate with perceptive state, moreso than the steady-state dynamics. This view has experimental evidence from several different organisms (See the Rabinovich link) but the most notable example is Locust olfactory states.

The Rabinovich paper above is really the goldmine for this question, including **fMRI evidence**, but another source of **fMRI theory** in relation to brain states is Karl Friston's Free Energy Principle for the Brain
> 5 votes

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Tags: philosophy-of-mind, fmri
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# Question
Title: What is the scientific basis for long-term negative physiological effects of overstudying?
I am interested in long term negative physiological effects that some students experience following overstudying.

* What is the scientific basis for overstudying?
* Is over studying correlated with long term decreases of cognitive ability?

# Answer
The research literature on stress in general and burnout in particular would be relevant. The stress literature is massive and there are studies that have a particular focus on students.

For example Jacobs and Dodd did a study on college student burnout:

> Measures of social support (Multidimen- sional Scale of Perceived Social Support), personality (General Temperament Survey), and workload were related to psychological burnout (Maslach Burnout Inventory) among 149 college students ( M = 20.8 yrs.). High levels of burnout were predicted by negative temperament and subjective workload, but actual workload (academic and vocational) had little to do with burnout. Low levels of burnout were predicted by positive tempera- ment, participation in extracurricular activities, and social support, especially from friends.

They also cite some of the literature on stress in college students:

> there has been a substantial amount of research on stress among general college students. Stress has been shown to be correlated with college students’ health behaviors (Weidner, Kohl- mann, Dotzauer, & Burns, 1996), anxiety concerning exams (Abouserie, 1994; Ever- son, Tobias, Hartman, & Gourgey, 1993; Sloboda, 1990), self-esteem (Abouserie; Newby-Fraser & Schlebusch, 1997), and coping strategies that students use (Dwyer & Cummings, 2001). To the extent that stress is an important component of burnout (Maslach & Jackson, 1981), this research is relevant to the development of a model of burnout among college students. Between classes, exams, employment, and extra- curricular activities, students are likely to experience high levels of stress, but do they experience burnout? Much research is needed to determine the prevalence of burnout, to identify important intrapersonal and interpersonal factors that influence burnout, and to develop effective inter- ventions to prevent and reduce burnout in college students.

### References

* Jacobs, S.R. & Dodd, D. (2003). Student burnout as a function of personality, social support, and workload. Journal of College Student Development, 44, 291-303.
> 6 votes

# Answer
You've actually stated 2 questions in one. The second one is answered by Jeromy, the burnout or burnout-like states are the consequence of any overworking. I would also add the health problems, but those are not particularly on topic.

When it comes to the reasons, the learning can become the **addiction**, as most of the things you do. It can become **obsession**. There are people who are **collecting knowledge**, and want to have as much facts as possible in their heads, such as the other are collecting the coins or stamps or anything else.

I personally know many people, which, during their studies, have spent most of their time in the library, while their effects were not better as those of their collegues, who have spent not as much as the half of that time learning. That people were simply like ill when they weren't learning, they couldn't find their place. Many of them are now internet-addicted or have alcohol problem. It seems to be the neurotype, that easily becomes obsessed about something (therefore, extremally vulnerable to addictions).
> 2 votes

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Tags: learning, educational-psychology, stress
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