# Question
Title: How is the type of memory that is passed through generations called?
It has a name. I thought it was called 'collective' memory. .. But I cant find any articles or information about it.. So I guess it has a different name.

There were a few cases where children were successful in recalling the memories of their past ancestors.

How is that type of memory called? and are there articles about it?

**UPDATE**

For the skeptics, watch the few first minutes of this doc..(or all of it)

```
https://www.youtube.com/watch?v=uBkJLTTea34

```

I did learn in my first psychology lessons about that memory. I cant remember wellthe case study that I studied.. but it involved a non-speaking German woman who after being hypnotized was able to talk German and recall her past life.

# Answer
I'm not sure about children recalling memories of their ancestors, but there is such a thing as **Genetic Memory**.

In one study mice who were trained to fear a specific smell passed on their trained aversion to their descendant. Who were then extremely sensitive to, and fearful of the same smell, even though they had never encountered it, nor been trained to fear it.

> We found that the behavior and structural alterations were inherited and were not socially transmitted from the older generation.

Reference:

Dias, B. G., & Ressler, K. J. (2014). Parental olfactory experience influences behavior and neural structure in subsequent generations. Nature neuroscience, 17(1), 89-96.

However I can't really find any evidence of this existing in humans.
> 9 votes

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Tags: memory, terminology
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title: Is there a way to avoid false memories?

text:
# Question
Title: Is there a way to avoid false memories?
I saw a video on how interrogators used manipulation on the victim/criminal which lead to innocent people being arrested and one way of doing that was using false memories in which the person was giving altered facts about what happened to the point where the person really thinks they did the crime. Even people with hsam(highly superior autobiographical memory) were more susceptible to false memories. Is there any way to avoid having false memories.

# Answer
Several studies using word lists have tried to see if informing participants of false recall would make them less likely to form false memories, results are a little mixed:

> 1) Although subjects were not able to perform accurately under these conditions, the warning instruction did attenuate the false recognition effect. This illusion of memory appears to be remarkably robust and little affected by the instructional manipulations.
>
> 2) forewarning did not eliminate the false recognition effect, as these subjects and those in the other groups made numerous false recognitions in this task.
>
> 3) When a warning about false recall was provided, young adults virtually eliminated false recall by the second trial. Even though old adults also used warnings to reduce false recall on Trial 1, they were unable to decrease false memories across the remaining four study–test trials. Old adults also reduced false recall more with slower presentation rates. These findings suggest that old adults have a breakdown in spontaneous, self-initiated source monitoring as reflected by little change in false recall across study–test trials but a preserved ability to use warnings and slow presentation rates to reduce false memories.

References:

1) McDermott, K. B., & Roediger, H. L. (1998). Attempting to avoid illusory memories: Robust false recognition of associates persists under conditions of explicit warnings and immediate testing. Journal of Memory and Language, 39(3), 508-520.

2) Gallo, D. A., Roberts, M. J., & Seamon, J. G. (1997). Remembering words not presented in lists: Can we avoid creating false memories?. Psychonomic Bulletin & Review, 4(2), 271-276.

3) Watson, J. M., Mcdermott, K. B., & Balota, D. A. (2004). Attempting to avoid false memories in the Deese/Roediger—McDermott paradigm: Assessing the combined influence of practice and warnings in young and old adults. Memory & Cognition, 32(1), 135-141.
> 4 votes

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Tags: memory
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# Question
Title: Just because masturbation doesn't interfere with everyday life, why aren't higher rates considered an addiction?
The common theme in most studies/articles about masturbation is that as long as the act does not interfere with everyday life, it's not considered a problem.

**However, just because it doesn't interfere with everyday life, why is frequent NOT considered an addiction?**

(For example, some people are addicted to marijuana or cocaine but are still functional, however, it is still an addiction.)

> This depends on the age, health, and personal needs of a guy. For instance, a survey on a popular masturbation site found that the average 13-year-old masturbates three times a day with over 10 percent masturbating over 6 times!

It sounds pretty clear that there is a strong, overpowering urge (regardless of reason) that has the individual repeating the act, in some cases many times a day.

So just because they can still get to work or turn in assignments at school/college, why is this not an addiction?

Ref. http://wiki.answers.com/Q/How\_often\_do\_most\_males\_masturbate

# Answer
Gary Wilson notes that porn combined with masturbation could be an addiction. Masturbation by itself, however, seems to be completely natural. There seems to be two schools of thought on this topic: (i) masturbation is addiction, (ii) masturbation is not an addiction. People note that porn is an addiction due to the novelty of it.

Also sex addiction is **not** the same thing as porn addiction.
> 2 votes

# Answer
The *frequency* of a behavior is not what makes that behavior an addiction.

For example, take walking. Most people take hundreds, if not thousands of steps each day. Nevertheless walking is not considered an addiction in most cases. Why? It is not something that the organism must do to survive, it is a voluntary behavior, yet no-one would think you addicted to walking because you did *not* take the elevator or did *not* drive the 400 yards to the supermarket. On the contrary, it is generally recommended to walk whenever you can, for reasons of health.

The *urge* for a behavior does not make that behavior an addiction, either.

For example, most people feel a strong urge to eat, drink, sleep, defecate, and none of these behaviors are considered an addiction. Maybe sexuality is a physical need, and in the absence of a partner masturbation is better than "going hungry"?

The problem with masturbation is that even scientists find it difficult to look at it neutrally, because it is hard not to see it through the filter of our cultural norms on sexuality. Walking is not a taboo, it can be done in public and with anyone you want. Eating and sleeping can be done in public, although to a lesser degree, and even defecating is not suppressed with the same vehemence as sexuality: a man urinating against a tree in a park is not something you find overly idyllic, but most people would not call the police, because they know how it hurts to hold in, while a man masturbating in the same spot will find himself arrested rather quickly. Masturbation has been forbidden by religious rules, thought to cause illnesses, and today has the stigma of presumably signifying an inability to find a partner.

Once you strip away the morals and prejudices and look at masturbation with a cold eye, you will realize that many children indulge in it and only take a break while they are dressed. Children stop masturbating (in the presence of witnesses) only if they experience negative reactions to their behavior, i.e. only once they learn the norm that masturbation is something to be ashamed of.

It is this normative view from which a masturbating teenager might appear addicted. For the scientist, masturbation is a normal and healthy behavior, especially in a 13 year old teenager, who has gained a new function and a new level of sensory pleasure. For the scientist, it appears unnatural *not* to explore this ability.

As for masturbation in adults, as far back as 1948 Kinsey found that masturbation alleviates nervous tension and that men who masturbate lead a more balanced life. Sexuality appears not as voluntary as riding a bike, but rather has strong physiological and psychological effects that make sex appear to be normal and healthy behavior for an adult human being.

And if we have come to consider sleep lengths between four and twelve hours to be perfectly normal for adults of our species, why would we not be equally broadminded regarding sexuality? Maybe because indulging in any kind of pleasure is frowned upon in our performance-oriented society?

---

Sources:

* Kinsey, A. C., Pomeroy, W. B., & Martin, C. E. (1948). *Sexual Behavior in the Human Male*. Philadelphia: W. B. Saunders.
> 9 votes

# Answer
This is not my area, but I think the definition of **addiction** is contentious for many reasons.

Addiction often has normative implications; i.e., that addiction is bad. It can imply an inability to not do the act.

It doesn't seem useful to me to talk about being addicted to the needs necessary for survival, such as breathing, eating, excreting, modulating temperature, and so on. Sexual fulfilment is closely related to species survival, and as such is certainly a natural part of human existence.

It seems natural to ask the question of how often people masturbate. And with any such count, there will be people who do it more or less often. But in the absence of negative effects on others or the individual, why should anyone care how frequently someone masturbates? What would be gained from using the label of "addiction" based on frequency alone?

You might want to read up about discussions of hypersexuality and sexual addiction.
> 8 votes

# Answer
All three answers on this page take the stance that masturbation cannot be an addiction. Since this is a controversial topic, I'll play devils advocate:

Neurobiologically addiction is marked by

1. Stress surfeit
2. Reward deficit
3. Stimulus-response perseveration
4. Self-regulation disorder

(I got this from Dr. George Koob.)

So if masturbation starts losing its appeal, and is just done because it's stressful not to do it, then yes, I'd say that's evidence for the underlying neurological changes of addiction.

As for the comment that an "urge for a behavior does not make that behavior an addiction," I agree but I think urges are tightly coupled with addiction formation. An urge is evidence of a mesocorticolimbic association between a stimuli and response. When this connection is recognized by society as an "addiction" is just a matter of degree.

Perhaps, if you could measure your subjective experience of masturbation over time, you'd have a better idea of when you became addicted: specifically when masturbation only gets you to your former baseline levels of satisfaction. So yes, maybe the urge isn't enough to call it addiction. But it's at least evidence that your brain is busy forming one.
> 0 votes

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Tags: measurement, sex-differences, addiction, sexuality
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# Question
Title: Does knowledge of tests like Iowa Gambling and Wisconsin Card-Sorting task enable a person to fake the test?
I am interested in tests like the Iowa gambling test and the Wisconsin card-sorting test. If a patient understands how such a test works and the goals of the test, does this bias the measure obtained? What test-taker can fake via higher cognitive function that might be intact, and what will be impossible to fake?

I imagine that the speed of taking a test might be a limiting factor. So if the rate of card picking is high, a patient may perform in a default way and be unable to apply higher cognitive control. Or if the patient tries to beat the test using knowledge about it, this will be evident in that the patient will take more time.

# Answer
Yes, knowing they are under an Iowa (or Wisconsin) test will change their behavior---and most likely create all sorts of biases in the results.

And you're probably right; time constraints will most likely place subjects into system1 thinking.

Subjects' having knowledge about an experiment may generally ruin it, for it can make testability collapse (how will others reproduce the results?). There are, moreover, all sorts of confounding factors that may directly influence subjects' behavior. Also, one cannot argue that 'they were concentrated on the task at hand', as they *knew* what was expected. One of the basis of empiricism is to not intervene (as in the Milgram Authority experiment, for instance). In most experiments, subjects will either hear a fairytale story of what they are being asked to do, or are simply told no background story. For example, experiments on priming with money generally hide the goals from subjects (See also Bargh and colleagues experiments on priming, which follow the same route, and were considered extremely controversial by psychologists until the last years).

Of course, this is **not** a straightjacket rule. One can do psychological experiments in which the subjects know what they must do and they should only "respond truthfully". Perhaps the most famous example of those was Ariely's "adult" experiment (It's quite a read). I have also conducted experiments in which subjects knew the goals completely, but one (control) group could not achieve it (low-skill group versus high-skill group, such as chess grandmasters). Ideally, however, subjects should be blind to the *actual* objective of the test conducted.
> 3 votes

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Tags: cognitive-psychology, cognitive-neuroscience, test
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# Question
Title: Is consciousness a sub product of the brain or is there a duality?
I am trying to understand what consciousness is, based on my basic knowledge of our senses, artificial intelligence (computer vision, specifically) and some philosophy. Here's my reasoning:

As far as I understand it from my Neural Network class, each eye captures the light and transmits it through electric signals to the brain. Each action potential can be seen as a binary 1, no activity as a 0.

This stimulates some of the neurons in the visual cortex, which allows our brain to interpret and understand what the eyes have captured.

In computer vision, this is where "sight" ends: the computer detects what's in the image, based on its knowledge base - its training set - and that's it.

So why does the human brain take the extra steps of combining both signals into an image - i.e translating the different waves of the electromagnetic spectrum into shapes, colors, etc -, turning it upright and displaying it to ourselves?

The same could be said, as far as I know it, about the other senses: hearing would be detecting vibrations in the air, but the brain also translate these into sounds.

Does this hint that Descartes' dualistic definition could be true, that our consciousness is separate from the brain? Or could consciousness be a sub product of the brain, a consolidation of what each one of its areas are processing, in order to better understand the world (as in Stanislas Dehaene's workspace neurons cognitive model)?

---

**edit**: I've been thinking a bit more about the subject. If there are workspace neurons responsible for consciousness, then there should be a region of the brain that is constantly active, at all times.

After a bit of - *online* \- research, I've stumbled upon the Default mode network (DMN), which is anti-correlated to the Task-positive network (TPN). Interestingly, the DMN is active when the individual is not focused on an activity - at rest. Furthermore, there is a possible increase in connectivity between DMN's nodes during REM sleep - when we dream. On the other hand, TPM is most active during attention-demanding tasks. It has therefore been theorized that both are elements of a single default network with anti-correlated components (in an scientific paper behind a pay-wall, so I'm quoting Wikipedia).

Plus, both networks involve the fronto-parietal attention network, where it is believed the workspace neurons are located.

I couldn't help correlating the DMN and TPN to Carl Jung's theories of the Conscious and the Unconscious - which I am particularly fond about. If these wild conjectures I am forming are correct, then we could have the following (oversimplified) neural correlate of consciousness:

In this idea, exchanges between TPM and DMN occur through neurotransmitters, while exchanges between the conscious and unconscious happen using psychic energy (as in the energy from the psyche, *not* supernatural powers). Furthermore, the collective unconscious would then be inherited from human to human - embedded in our DNA. If true, then there would be discernible patterns in a newborn's brain...

So, going back to A.I, a conscious agent would not, theoretically, be a single agent, but instead a multi-agent collaborative system...

Now, I have very basic knowledge and lack scientific research on these topics, but I am interested in learning a LOT more. Is this theory absurd and blatantly wrong, or is it worth pursuing as a hypothesis?

# Answer
Your question is about the hard problem of consciousness, which is basically the question of how qualia can be explained in a mechanistic way. As alluded to by the name of the problem, it's hard to give a satisfactory answer. The answer right now is: we don't know.

There are some theories about how qualia and consciousness could have a neural basis (see this question and this wikipedia article). But none of these theories are widely accepted by cognitive scientists and there is still considerable debate over the issue.

Your question also illustrates another philosophical issue in the philosophy of mind. You asked:

> So why does the human brain take the extra steps of combining both signals into an image - i.e translating the different waves of the electromagnetic spectrum into shapes, colors, etc -, turning it upright and *displaying it to ourselves*
>
> (emphasis mine)

The idea that conscioussness and qualia reconstruct the world and then we act and perceive on that world creates a problem: how do we act an perceive on that world? Do we reconstruct it? If so, then we are back to the original problem. This is called the homunculus argument, and it illustrates the fact that we haven't explained anything if we posit that the purpose of qualia is to reconstruct what's already out there.
> 5 votes

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Tags: cognitive-neuroscience, vision, consciousness, philosophy-of-mind
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title: How common is alien hand syndrome?

text:
# Question
Title: How common is alien hand syndrome?
The impression that I got from looking at a couple of articles on alien hand syndrome was that it was an extremely common or basically guaranteed result of getting a callosotomy to treat severe epilepsy. However, I just ran into a study that showed essentially no effect from being born without a corpus callosum:

> The pattern of anatomical features of the brain revealed by magnetic resonance imaging (MRI) is described in six patients incidentally identified as having acallosal brains... Conventional clinical testing revealed no abnormalities except a slight impairment of walking heel-to-toe in two patients. None of the patients had subjective restrictions of activities of daily life, which shows the efficacy of unknown compensatory processes.

## Questions

* **How common is alien hand syndrome?**
* **How frequently do callosotomies result in alien hand syndrome?**
* **How often is there severe damage to the corpus callosum unaccompanied by alien hand syndrome?**
* **How many cases of alien hand syndrome are there with no visible damage to the corpus callosum?**

# Answer
Alien hand syndrome (AHS) is an extremely rare disorder. It is so rare, there appears to be no available prevalence studies. In the AHS literature, case studies are therefore nearly universal. For all intents and purposes, it is reasonable to say that AHS appears to be a disease so rare that the empirical prevalence rates are in every listed case statistically indistinguishable from zero.

One recent paper by Sarva, Deik and Severt (2014) reviewed 109 studies on AHS patients. Their first and foremost result was the finding that there appears to be three overlapping types:

* **Frontal:** Associated with involuntary groping, grasping and tool use.
* **Callosal:** Associated with intentional opposing movements.
* **Posterior:** Associated with avoidance responses and uncoordinated movements.

Interestingly, they also briefly report an even rarer **alien limb phenomena** involving the leg!

Based on their review, Sarva, Deik and Severt (2014) suggested that different types of AHS may be caused by different kinds of disruptions to an executive system which is partly responsible for resolving between-task conflicts and prioritizing actions, causing disconnects and impaired coordination between hemispheres. They conclude:

> Our understanding of underlying mechanisms remains incomplete, but **evidence from pathological and functional neuroimaging studies suggests a role for network disruption causing bihemispheric disinhibition and/or interhemispheric disconnection.** Depending on the variant and the underlying pathology, apraxia, neglect, cortical sensory deficits, and other neurologic abnormalities may also be present in varying degrees, likely explaining the considerable phenotypic variability among patients. Functional imaging studies likely will continue to expand our knowledge of the pathophysiology of AHS, but **the limited number of patients in these studies and the diverse underlying pathologies should raise caution when attempting to generalize their results.**

## References
> 4 votes

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Tags: abnormal-psychology, neuroanatomy, lateralization
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# Question
Title: How does the group that is not stressed and not reactivated act as a control for time in Schwabe & Wolf 2010?
Schwabe and Wolf (2010)

> Rodent studies suggest that memory reconsolidating is impaired by stress. Here we examined in healthy humans the effect of stress on the reconsolidation of autobiographical memories. Participants recalled positive, negative and neutral episodes from their recent past and afterward exposed to a stressor (socially evaluated cold pressor test) or a non-arousing control condition. Additional groups of participants were exposed to the stressor without prior memory reactivation or were neither stressed nor asked to recall episodes from their past. Stress after memory reactivation impaired the memory for the neutral episodes 1 week later....

How is the group that is not stressed and not reactivated (control) act as a control for time? Or rather what does "control for time" mean?

The researchers wrote "To control for the effect of time on memory, we had another control group that was not stressed and did not reactivate experiences from their past."

I understand that the group makes a good baseline for comparing other results to, but where does time come into it?

**References**:

# Answer
> 3 votes
It appears that they tested all of the participants (control & stress) at the same time:

> * Memory was assessed 24 h after learning. According to the model by Joels and colleagues (2006), it can be predicted that learning under stress enhances memory, in particular for stress context-related information
> * Twenty-four hours after learning, participants returned to the laboratory and completed a free recall test
> * Immediately after the free recall test, participants were given a recognition test.
> * All testing took place in the morning between 8 am and 1 pm to control for the diurnal variation of the stress hormone cortisol. On day 1, participants heard a list of eight neutral words that were related to the stressor as well as eight negative, eight positive and eight neutral, stressor-unrelated words while they were exposed to stress or a control condition (for details see below). On the following day, participants returned to the laboratory and completed a free recall and a recognition test for the words they heard the day before.

I can't find anywhere within the text that says "To control for the effect of time on memory, we had another control group that was not stressed and did not reactivate experiences from their past."

They found that:

> Learning under stress reduced both free recall and recognition performance 24 h after learning.

All taken from your reference:

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Tags: memory, cognitive-neuroscience, experimental-psychology, long-term-memory
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# Question
Title: Does an action potential abolish an excitatory postsynaptic potential?
From some sources, I've read that excitatory postsynaptic potentials (EPSPs) decay over time, which would imply that they aren't abolished by action potentials. However, other sources seem to indicate the opposite (although I may be misunderstanding them). Plus, the classical leaky-integrate-and-fire neuron model implies that EPSPs are abolished by action potentials (although this could well be a simplification). Does the refractory period of an action potential affect its originating EPSP? Or is it a separate phenomenon?

# Answer
While model neurons like the leaky integrate and fire may use a simplification in which the neuron forgets all previous information when it emits a spike, in a biological neuron, the synapse and the soma are relatively electrically isolated from each other, so the voltage activity of the action potential does not make the synapse "forget" the EPSP. Although see back propagating action potentials for a mechanism for somatic action potentials to affect dendritic processing. (http://www.ncbi.nlm.nih.gov/pubmed/8107777)
> 5 votes

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Tags: neuroscience, theoretical-neuroscience, neural-network
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# Question
Title: How many action potentials from presynaptic neurons would be required to make a postsynaptic neuron fire?
I am looking for a rough estimation of the number of action potentials from other neurons required to cause a neuron to fire?

I read here that a potential of ~ -55mv must be reached before an action potential is fired in a neuron, my thought is how many action potentials from other cells would (roughly) be required to reach this - and in what required time (if it matters)?

*I am not a neuroscientist and suspect this question is unanswerable but though this was the place to ask!*

# Answer
It is highly variable, depending on the strength and placement of the synapse (which in turn depends on synapse activity and how often the two neurons fire together, among other things). The wikipedia page here is a pretty good place to start, or if you want more detail on how that pulls together in an actual system, this paper is a good place to start.
> 4 votes

# Answer
It is very very important to note that in the brain, most neurons are receiving input from way more excitatory synapses than necessary to bring the neuron to threshold. The thing is that they are also receiving input from a huge number of inhibitory synapses as well. This means that it is not how many inputs that are active at a given time that determines whether a neuron fires or not, it is the *balance* between excitation and inhibition.

see: attalah and scanziani 2009 (experiment) http://labs.biology.ucsd.edu/scanziani/documents/AtallahNeuron09.pdf

okun and lampl 2008 (experiment) http://www.nature.com/neuro/journal/v11/n5/full/nn.2105.html

van vreeswijk and sompolinsky (theory) http://www.sciencemag.org/content/274/5293/1724.short
> 5 votes

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Tags: neuroscience, theoretical-neuroscience, neural-network
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# Question
Title: Are there theories on how vocabularies for the Semantic Pointer Architecture are created?
The semantic pointer architecture is a vector symbolic architecture where high-dimensional sparse vectors represent concepts. These concepts can be mathematical, linguistic or sensory. In all of the experiments I've seen these vectors are assigned randomly

In the case of mathematical and linguistic, are there any theories or experiments investigating how these vectors may be formed? Is this a relevant topic for investigation? If not, why?

# Answer
I do not know for sure, but I believe that the vectors would be created in a domain-specific manner. Vectors in the visual system would be created in a way that is particular to the needs of visual processing, etc. The reason why the vectors are represented as random in the semantic pointer architecture, is because from the point of view of the architecture itself, the information encoded in the vector is irrelevant. What is relevant is how to manipulate those concepts once they are already formed.
> 2 votes

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Tags: theoretical-neuroscience, cognitive-modeling, spa
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# Question
Title: How to compute weights and bias for a McCulloch-Pitts neuron?
I am trying to learn how to manipulate McCulloch-Pitts neurons in order to determine their weights and bias based off of inputs. In this example I have inputs:

x, y, z ∈ {−1,1}

The neuron's output is z if x = -1 and y = 1, and is -1 otherwise.

How do I compute the weights and bias for the neuron? An example or link to an example would be greatly appreciated. (Having a hard time finding examples online). Thanks!

So far I have been using the equation out = sgn((w1)(in1) + (w2)(in2) + (w3)(in3) - theta), but I am unsure whether or not I am taking the correct initial steps to solving this problem.

# Answer
> -1 votes
The weights and bias for a given neuron depend on the task you are trying to solve. Each computation will have a different set of weights that will implement it.

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Tags: theoretical-neuroscience
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# Question
Title: Biologically plausible cognitive model of Wisconsin card sorting task
As discussed previously, there are a wide range of models that have been applied to the Wisconsin card sorting task. However, which one is most biologically plausible? That is, uses a realistic model of neurons, respects the constraints of the human brain and maps readily onto experimental data.

# Answer
> 5 votes
Amos (2000) and Monchi et al. (2000) use the similar approach of assigning each card attribute to a node and using mutual inhibition to choose the right one. Although their models are biologically plausible and make many neuroanatomical predictions, they are functionally implausible. Their networks are created for the unique purpose of of completing the WCST. This type of specialization isn't found in the brain as far as I know. I'm also having a really hard time understanding on Monchi is using Leaky-Integrate-Fire neurons to compute functions, but that might be a topic for another question.

Rougier et al. (2005) use Leabra, which has been criticized for it's lack of biological plausibility. For further elaboration on these criticism, which is mostly centered around the biologically-implausible use of a Winner-Takes-All computational block being used, check out How to Build a Brain by Chris Eliasmith.

Bishra et al. (2010) only define symbolic rules. There's no neuroanatomical mapping. Consequently, although they claim tuned parameters could predict performance, there doesn't seem to any definition of where these parameters come from.

In conclusion, although none of the approaches are perfectly biologically plausible, Amos and Monchi seem to definitely come out on top. Although hard-coded concepts such as the possible parameters for matching are totally acceptable, a model that integrates with a larger more general system while remaining biologically plausible would be ideal.

# Answer
> 3 votes
Rigotti et al. have a model of the wisconsin card sorting task using a neural network and compare it with data from prefrontal cortex http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2967380/

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Tags: cognitive-neuroscience, theoretical-neuroscience, cognitive-modeling, computational-modeling
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# Question
Title: What are the underlying mechanisms for optimism bias?
I have asked a question before about how does smoker's decision react to new personal health information. Link here. How do people estimate smoking's impact on their mortality?

Now I have a follow up question. Psychologists have termed smokers's over confidence about their chance of not being hurt by smoking as optimism bias. My question is: has there been any neuroscience, medical or psychology research about the mechanisms of optimism bias?

# Answer
**Optimism bias** refers to a general human tendency to underestimate the likelihood of negative events, and conversely, to overestimate the likelihood of positive events, when making predictions about which events will occur to oneself in the future.

It is a cognitively interesting and widely studied phenomenon, because the human brain and human behavior are broadly believed to be highly adaptive, but optimism bias demonstrates that in many cases, we maintain beliefs *in spite of* the available evidence. This is a somewhat less surprising finding nowadays, since modern psychology has largely abandoned the idea of humans as rational actors. There was a time, though―a time, in Skinner's heyday, when optimism bias was considered baffling and proper paradoxical.

Sharot (2011) suggested that optimism bias is cognitively maintained by a bias towards updating our beliefs in response to positive prospective information than to negative prospective information. She attributed this to decreased encoding of negative-update information in the right inferior frontal gyrus. In another paper, Sharot, Riccardi, Raio and Phelps (2007) had reported this decreased encoding may be mediated by activity in the rostral anterior cingulate cortex (rACC) and amygdala:

> Here we report that \[optimism bias\] was related specifically to enhanced activation in the amygdala and in the rostral anterior cingulate cortex when imagining positive future events relative to negative ones, suggesting a key role for areas involved in monitoring emotional salience in mediating the optimism bias.

In other words, the amygdala appears to evaluate the emotion valence of the information, evoking a regulatory response in the rACC, which is implemented as an inhibited update to negative-update evidence, or optimism bias, by the right inferior frontal gyrus.

## References
> 3 votes

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Tags: cognitive-psychology, cognitive-neuroscience, decision-making, bias
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# Question
Title: How does the alpha brain wave frequency range distribute over the population?
Alpha brain waves show up in your EEG when you close your eyes. Alpha waves are brain waves between 8 and 13 Hz.

How does this frequency range distribute over a population of people?

# Answer
> 4 votes
Alpha oscillations vary in frequency within a single subject from brain area to brain area (Başar, 2012), likely because there is not a single phenomenon underlying all examples of alpha oscillations. At this point in time, an answer to this question would be very difficult because we don't even know what alpha oscillations are.

**Reference**

Başar, E. (2012). A review of alpha activity in integrative brain function: fundamental physiology, sensory coding, cognition and pathology. *International Journal of Psychophysiology*, *86*(1), 1-24.

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Tags: eeg
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# Question
Title: What research has been done on brain-to-brain interfaces?
Is there an existing research area focusing on brain to brain interfaces? If so, what are some papers that have been published in this area?

# Answer
> 10 votes
Rao et al. 2014 claims to be the first demonstration of a brain-brain interface in humans, using EEG and TMS.

> **Abstract**
>
> We describe the first direct brain-to-brain interface in humans and present results from experiments involving six different subjects. Our non-invasive interface, demonstrated originally in August 2013, combines electroencephalography (EEG) for recording brain signals with transcranial magnetic stimulation (TMS) for delivering information to the brain. We illustrate our method using a visuomotor task in which two humans must cooperate through direct brain-to-brain communication to achieve a desired goal in a computer game. The brain-to-brain interface detects motor imagery in EEG signals recorded from one subject (the “sender”) and transmits this information over the internet to the motor cortex region of a second subject (the “receiver”). This allows the sender to cause a desired motor response in the receiver (a press on a touchpad) via TMS. We quantify the performance of the brain-to-brain interface in terms of the amount of information transmitted as well as the accuracies attained in (1) decoding the sender’s signals, (2) generating a motor response from the receiver upon stimulation, and (3) achieving the overall goal in the cooperative visuomotor task. Our results provide evidence for a rudimentary form of direct information transmission from one human brain to another using non-invasive means.

# Answer
> 6 votes
There were 2 pioneering papers published in 2014, both claiming to be the first in humans.

Grau et al (2014) was published first (August), but the actual experiment was conducted later (March 2014):

> Here we show how to link two human minds directly by integrating two neurotechnologies – BCI and CBI –, fulfilling three important conditions, namely a) being non-invasive, b) cortically based, and c) consciously driven (Fig. 1). In this framework we provide the first demonstration of non-invasive direct communication between human minds.

Rao et al (2014) (mentioned by @Josh) was published later (November), but the experiment itself was conducted earlier (August 2013).

> We describe the first direct brain-to-brain interface in humans and present results from experiments involving six different subjects. Our non-invasive interface, demonstrated originally in August 2013, combines electroencephalography (EEG) for recording brain signals with transcranial magnetic stimulation (TMS) for delivering information to the brain. ... Our results provide evidence for a rudimentary form of direct information transmission from one human brain to another using non-invasive means.

Both experiments used an EEG to detect activity in the brain of the sender, and TMS to stimulate activity in the brain of the receiver. The 2 experiments had slightly different approaches however. In the Rao et al study, the motor cortex was used, whereby the sender clicking a mouse caused the receiver's hand to twitch. This was used to play a simple video game where one player had access to information that the other player did not. In the Grau et al study, the sender's motor cortex was also used, but on the receiver side, the TMS was directed to the occipital lobe - the visual cortex - causing flashes of light to appear to the receiver. This set up was used to deliver a message, rather like a telegraph, using encoded "bits" (1s and 0s represented by the light flashes). This is more like telepathy, albeit a very primitive version of it.

A TED talk by Miguel Nicolelis on Brain-to-Brain interfaces, mostly focusing on rats and monkeys, but he mentions about humans at the end.

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Tags: reference-request, theoretical-neuroscience, brain-computer-interface
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title: Slices and aquisition of fMRI

text:
# Question
Title: Slices and aquisition of fMRI
Is a slice obtained with functional MRI (fMRI) always 3-dimensional, i.e., x-y-z? I thought that a typical fMRI scan's total imaged volume would be 4D, i.e., made up of 3D slices plus time.

# Answer
> 3 votes
I will focus on question #1:

Analysis of MRI scans is typically done using **voxels** (Fig. 1). Voxels have a volume defined by three dimensions (length, width and depth).

Voxel analysis. Source: Philips

The slice thickness plus the 2D in-plane resolution (pixel size) yields the voxel size. The time to scan a slice can be regarded to be negligible. Making a scan consisting of multiple slices takes time. Hence, the time dimension is not directly relevant for voxel size. Practically, voxel size depends mostly on slice size, as well as the capacity of the scanner. More Tesla's makes smaller voxels possible.

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Tags: neuroimaging, fmri
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# Question
Title: What is the upper bound on rate of learning in young adults?
I was wondering how a normal adult in their 20s could best structure their life to make best use of their capacity to learn. I am no expert in cognitive science, so I assume just a really common definition of "learn" here. We might measure this by, for example, hours of sustained, intense study per 24 hrs. I realize my question might be a major oversimplification, leaving out factors like stress.

If there is some upper bound on how quickly learning occurs, then there may be little point in studying more than, say, 6 hours per day. Does anyone know of any research which shows some general, asymptotic upper bound for learning in adults (20-30)?

Anectodal examples might also be useful. What are some examples of how highly accomplished adults structure their days?

# Answer
> 2 votes
Karl Ericsson, on whose work Malcolm Gladwell based much of his popular *Outliers*, has expressed on a number of occasions that the optimal amount of practice time a day is around 3-5 hours, depending on domain.

There is a great deal of research in the expertise literature, but Ericsson, Krampe, Tesch-Römer (1993) is a seminal (if not uncontroversial) paper in the field which provides a very solid introduction. They reported evidence for the idea that practicing more than four to five hours a day was not associated with higher achievement within a domain. To support this claim, among others, they drew on a number of sources, including:

* **Literature review**

> A number of training studies in real life have compared the efficiency of practice durations ranging from 1-8 hr per day.These studie sshow essentially no benefit from durations exceeding 4 hr per day and reduced benefits from practice exceeding 2 hr (Welford, 1968; Woodworth & Schlosberg, 1954). Many studies of the acquisition of typing skill (Baddeley & Longman, 1978; Dvorak et al., 1936) and other perceptual-motor skills (Henshaw & Holman, 1930) indicate that the effective duration of deliberate practice may be closer to 1hr per day. Pirolli and J. R. Anderson (1985) found no increased learning from doubling the number of training trials per session in their extended training study.

* **Retrospective estimates from expert violin players**

> When the duration of all music-related activities was summed across the diary week, the average number of hours per week was 50.6, and no reliable differences between the groups were found. Of the eight activities judged to be highly relevant to improvement of violin performance, only two had an average duration across all three groups exceeding 5 hr per week. These two activities were practice alone (19.3 hr per week) and sleep (58.2 hr per week).

* **Biographies of accomplished scientists and intellectuals**

> Biographies report that famous scientists such as C. Darwin, (E Darwin, 1888), Pavlov (Babkin, 1949), Hans Selye (Selye, 1964), and Skinner (Skinner, 1983) adhered to a rigid daily schedule where the first major activity of each morning involved writing for a couple of hours. In a large questionnaire study of science and engineering faculty, Kellogg (1986) found that writing on articles occurred most frequently before lunch and that limiting writing sessions to a duration of 1-2 hr was related to higher reported productivity. \[...\]
>
> In this regard, it is particularly interesting to examine the way in which famous authors allocate their time. \[...\] Almost without exception, they tend to schedule 3-4 hr of writing every morning and to spend the rest of the day on walking, correspondence, napping, and other less demanding activities (Cowley, 1959; Plimpton, 1977).

However, many questions remain regarding the generalizability of deliberate practice. More recent research has suggested that Ericsson's theory may not be equally adequate for all domains, and nearly irrelevant to some. For a more critical review of Ericsson's work, please see my related answer on, "Do 10.000 hours of practice make you an expert?".

## References

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Tags: learning, training, expertise
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# Question
Title: Does the Minnesota 12 steps model really produce an effective change in the treatment of drugs addictions?
The Minnesota 12 steps model claims to cure drug addiction, but doesn't deeply deal with the personality structure underlying addiction. We know today how addiction is a problem with an enormous range of factors causing it, being personality or/and psychopathology and coping strategies some of the most important.

The method uses 12 steps to free individuals from drugs, but it doesn't use any deep approach to their personalities and its duration is also too short to do it ("The primary care program was intended to last up to 60 days in a residential setting", " "insurance companies then set 28 days as a reimbursement guideline in order to ensure sufficient coverage"(1). There is even little evidence that this model is effective, and it received criticisms.

Hence my questions:

* Is it really producing changes, or only temporary changes which can collapse every time that personality is challenged?
* Can it be realistically expected that the individuals treated by this method have their personalities really transformed and would never feel the necessity of consuming drugs, or have other type of addictive behaviours?

(1) http://www.ncbi.nlm.nih.gov/books/NBK64351/

# Answer
> 4 votes
Grønbæk and Nielsen (2007) conducted a randomized, controlled study of the Minnesota model for treating alcohol dependence in Denmark. 148 alcohol dependent individuals participated. The study reported a significant difference in alcohol abstinence between control and treatment groups when data was aggregated over the one-year period. However, by the end of the one-year followup period, this difference had disappeared. They concluded:

> Twelve months after onset of treatment, the Minnesota day clinic treatment does not differ in effect from the much cheaper ‘standard’ public treatment. However, patients in Minnesota treatment were total abstainers throughout a longer period.

## References

* Grønbæk, M., & Nielsen, B. (2007). A randomized controlled trial of Minnesota day clinic treatment of alcoholics. Addiction, 102(3), 381-388.

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Tags: abnormal-psychology, personality, psychiatry, addiction
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# Question
Title: Can stress or training influence the perception of time?
I have had this experience that I fell with my bike on an icy street. During the fall, time seemed to slow down and I had an apparent age-long time window to stretch my hand and safely catch my fall.

A less anecdotal example is the following. Among jugglers I think it is a common phenomenon that once you get the hang of a trick, that at that point one comes to realize '*how much time one actually has to catch a ball and throw it back into the air*'. (I looked for references, but it at least applies to me, and I remember to have read it in juggling instruction material as well. I can try to find more evidence of this perceived time when needed).

Both examples show that the perceived lengthening of time appear to allow the body to make more coordinated movements within a given amount of physical time.

Now my question is, assuming physical time is constant (barred Einstein's relativity of time when travelling at great speeds):

> Is it true that **perceived time can change** under the influence of **stress** or due to **training**?

# Answer
Part of the difficulty in studying time perception is that memory is known to be biased by numerous factors including arousal and salience. So while people commonly report time slowing down during specific events, it is difficult to differentiate the effects of retroactive memory bias in encoding and recall from actual increased resolution in the perception of time and accelerated physical abilities or mental processes. For example, adrenaline is known to affect both physical response and memory consolidation.

One hint regarding the plasticity of the brain's actual perception of time comes from the temporal binding effect (nice review here). A variety of experiments show that the brain automatically recalibrates simultaneity amongst different neural processes through learning: That is, the brain processes different stimuli at different rates, but it learns to calibrate those processes so as to create the illusion that they occur at the same time:

> At least over a short time frame, our temporal perception of events is far from veridical, and multiple timelines are capable of dynamic recalibration.

In other words, there is no single perception of time, time is perceived at different rates by different parts of the brain, and then retroactively synchronized.

A more direct attempt to differentiate memory from perception was done by Stetson et al (2007). In this experiment, subjects were dropped 150 feet with no ropes or parachute - into a safety net. During the free-fall, they were asked to read numbers flashed on a wrist-watch. The numbers were flashed at different rates to test whether perception resolution was actually enhanced during the fall. Despite estimating their fall to take much longer than control subjects not performing this task (corroborating the effect of salience on memory), there was no evidence of increased time resolution:

> Our findings suggest that time-slowing is a function of recollection, not perception: a richer encoding of memory may cause a salient event to appear, retrospectively, as though it lasted longer.

However, this conclusion has been criticized by other authors as the failure to produce an effect on time perception may be due to the experiment not being frightening enough, for only testing visual perception, and that free-fall may actually distract from the reading task. Evidence from life-threatening events such as accidents and the performance of skilled individuals in extreme sports for example, suggests that increased time resolution, physical performance, and cognitive abilities during extremely stressful events may be possible:

> This evidence supports the suggestion by Arstila (2012) that humans possess a specialized hormonal or neurophysiological mechanism for high-speed cognition; and that this is activated inadvertently by real fear of imminent violent death in accidents, emergencies, and certain extreme sports; and may on some occasions be activated intentionally by individuals who have trained themselves to do so.

**Edit** (re updated question):

The latter paper - Buckley (2014) - summarizes research on the performance of experienced / trained / skilled individuals. Accelerated performance (physical and mental) is found in accidents in extreme sports, such as climbers in accidental falls; and in the performance of many physical activities:

> Less skilled participants perceive only confusion, and are likely to freeze, panic, or act in ways which increase danger (Buckley, 2012). It is also experience and training which allow skilled exponents of many physical arts to achieve feats which appear impossibly fast and precise. There are many examples in ball and boardsports, gymnastics, acrobatics, dance, martial arts, archery, shooting, swordsmanship, and in aircraft, car and motorbike racing and stunt driving.
> 9 votes

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Tags: perception, time
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# Question
Title: How did Fechner justify the assumption that the just-noticeable-difference in sensation is constant?
As stated here on Wikipedia:

Weber's law states that the-just-noticeable-difference (JND) of an intensity of a stimuli divided by the intensity of that stimuli is always constant.

Mathematically: $\Delta(I)/I=Constant$

... where $I$ here means the physical intensity of sound, light and so on. $\Delta(I)$ is the-just-noticeable-difference.

Then came Fechner and assumed that the-just-noticeable-difference "in sensation" of a stimuli is constant as well, hence: $\Delta(I)/I = Constant = \Delta(S)$

$\Delta(S)$ stands for the-just-noticeable-difference "in sensation."

On what basis was Fechner justified in assuming that the-just-noticeable-difference in sensation is constant?

# Answer
It was not an assumption; it was a decision. It allowed for better quantification, it gave an operational definition in increase in sensation, which allowed for more common ground in research between different labs. In a way, it's a definition by pure counting: when the subject feels a change in sensation, add one. Then this absolute scale is plotted against the ratio scale of increase in stimulation.
> 2 votes

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Tags: methodology, sensation
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# Question
Title: Why do difficult-to-learn subjects seem easier in retrospect?
**Background:** I have recently noticed that in class, that after I finished a unit, it seems less difficult than I expected it to be. It has happened in math, physics and electronics.

Is it possible that maybe those units were not even difficult in the first place? That it was just a matter of perception and first judgement, where you think to yourself "Oh lord, this unit is gonna be hell," and the mind plays along with that all through?

Why do difficult-to-learn subjects seem easier in retrospect?

# Answer
There are at least two different lines of research that are relevant here.

**Forecasting errors**

One large line of research has shown that are pretty bad in forecasting future events. This can be seen, for example, in the stable tendency to overestimate the affective impact of negative as well as positive events in terms of intensity and duration. In other words, if people are facing a situation that will likely be negative (such as an "it will be hell" class or exam), the prediction of their negative affective reaction (How long intense will it be? How long will I suffer?) is stronger than their actual reaction. This tendency has been called the **impact bias**. Numerous sources of the impact bias have been identified, a good starting point into this research are the (somewhat older) reviews by Wilson and Gilbert (2003, 2005). As an example, one reason for the impact bias in response to negative events is the so-called **immune neglect**, which refers to people's tendency to underestimate their skill in coping with such events.

**Below-average effect**

It is also possible to frame the situation in a way that implies a comparison to others: Maybe you expected a difficult class in that you expected to fare worse than your fellow students (and were surprised that you were not).

A line of research has shown that people can be pretty bad in ranking their own skill in comparison to others. Mostly, this surfaces in an above-average effect: Most people think that they are better drivers than others, for example, which is logically impossible. However, research by Justin Kruger (1999), for example, has shown that this holds only for relatively easy tasks. For difficult tasks, this actually turns into a **below-average effect**. That is, when people think that a task requires much skill (such as a difficult class or exam) most actually think that they are worse than other people. One explanation for this tendency is that people "anchor" their judgment of their own skill only on their introspected self-assessment and fail to consider that it will be difficult for others too (information about ourself comes more easily to the mind, after all).

**References**

Wilson, T. D., & Gilbert, D. T. (2003). Affective Forecasting. In M. P. Zanna (Ed.), Advances in experimental social psychology (Vol. 35, pp. 345–411). San Diego, CA: Academic Press.

Kruger, J. (1999). Lake Wobegon be gone! The “below-average effect” and the egocentric nature of comparative ability judgments. Journal of Personality and Social Psychology, 77, 221–232. doi:10.1037/0022-3514.77.2.221

Wilson, T. D., & Gilbert, D. T. (2005). Affective forecasting knowing what to want. Current Directions in Psychological Science, 14, 131–134. doi:10.1111/j.0963-7214.2005.00355.x
> 3 votes

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Tags: emotion, learning, metacognition, expertise
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# Question
Title: What is the subjective wellbeing instrument that is used by Science of Happiness for check-ins?
I am doing some work with students on happiness and thought it would be useful for us to have a look at their subjective well-being.

The EdX Science of Happiness course made use of weekly checkins like this one: https://ucbpsych.qualtrics.com/jfe/form/SV\_aVt9kWutzGlImwJ

The test is 6 questions, each one you are shown a drawing of a face with an emotion (3 positive, 3 negative) and you are asked to rate "To what extent does the character above match how you've been feeling lately?"

I'd like to learn more about this instrument. Like what research has been done to determine the validity of the measure, the origins of it, considerations when applying it.

I can't find any information on it, there doesn't seem to be a reference on the course page as to where it came from.

Does anyone have any ideas?

# Answer
The background of the measure can be found here.

The article implies that it is an ad-hoc measure of emotions created for this study:

> Every week, we checked in with our students to see how they were feeling. We showed them a sequence of six cartoon faces created by Pixar artist Matt Jones to convey fear, enthusiasm, anger, affection, sadness, and amusement (below). Under each, we asked them to rate, on a scale of 1 to 10, how much each face matched how they’d been feeling lately. Then we transformed their collective weekly ratings into a single score.

> The result? For students who responded at least 8 out of 10 times—suggesting that they were fully participating in the course—positive feelings went up, and up, and up. They felt progressively less sadness, anger, and fear, while at the same time experiencing more and more amusement, enthusiasm, and affection.
>
> We also invited students to fill out a brief battery of research-validated questionnaires that are regularly used to assess feelings like happiness, stress, flourishing, or satisfaction with life.

The last sentence suggests the ad-hoc nature of the measure (as compared to validated scales). Also, I couldn't track down any published research with this measure. The icons themselves stem from a collaboration of Dacher Keltner with Facebook, as described here, for example.
> 4 votes

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Tags: emotion, measurement, well-being
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# Question
Title: Can cats get depressed in a way similar to humans?
Most of the research on depression seems quite human focused. Can cats also get depressed in the same way there's depression for humans?

# Answer
> 7 votes
Human depression has been modeled in a variety of animal models, including cats (Wilner, 1984). Cats show comparable signs of distress when subject to maternal separation, including separation phenomena of protest, followed by despair. Although it is hard to project the DSM-V criteria onto cats, they can show comparable behaviors when subject to anxiety and stress.

<sub>**Reference**
**-** Wilner, *Psychoneuropharmacol* (1984); **83**(1): 1-16</sub>

# Answer
> 6 votes
There is a lot of research on depression in animals.

Wikipedia has a good summary of the comparison of depression between animals and humans:

> It is difficult to develop an animal model that perfectly reproduces the symptoms of depression in patients. Many animals lack self-consciousness, self-reflection, and consideration; moreover, hallmarks of the disorder such as depressed mood, low self-esteem or suicidality are hardly accessible in non-humans. However, depression, as other mental disorders, consists of endophenotypes\[5\] that can be reproduced independently and evaluated in animals.
>
> The following endophenotypes have been described:\[5\]
>
> * Anhedonia: The loss of interest is a core symptom of depression.
> * Anhedonia in rodents can be assessed by sucrose preference or by intracranial self-stimulation.
> * Behavioral despair: Behavioral despair might be assessed with tests such as the forced-swimming test or the tail suspension test.
> * Changes in appetite or weight gain: Depression is often associated with changes in appetite or weight gain, which is easily measured in rodents.
> * Neuroanatomy: Depressed subjects display decreased hippocampal volume and rodents exposed to chronic stress or excess glucocorticoids exhibit similar signs of hippocampal loss of neurons and dendritic atrophy.
> * Neuroendocrine disturbances: Disturbances of the hypothalamic–pituitary–adrenal axis (HPA) are one of the most consistent symptoms in major depression. The functionality of the HPA can be assessed by dexamethasone suppression test .
> * Alterations in sleep architecture: Disturbances in the circadian rhythm and especially in the sleep architecture are often observed in depressed. In rodents, it is accessible via electroencephalography(EEG).
> * Anxiety-related behavior: Anxiety is a symptom with high prevalence in depression. Therefore, animal models of depression often display altered anxiety-related behavior.

One of the early popular models of depression based on animal behaviour is learned helplessness theory:

> Learned helplessness theory is the view that clinical depression and related mental illnesses may result from a perceived absence of control over the outcome of a situation.

This has been replicated in many animals, including cats. (A nice review of learned helplessness in humans here.)

Modern theories of depression include many other causes besides learning, not all of which are applicable to animals. So ultimately, cats do get depressed, in a way similar in some respects to humans, but in other aspects, not the same.

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Tags: depression
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# Question
Title: Is it possible to improve interoceptive awareness/accuracy? If so, how?
For those unfamiliar, interoceptive awareness/accuracy involves awareness of, and sensitivity to, internal physiological sensations ("My heart is beating fast"). Interoceptive information is fundamental to how we conceptualize our affective experiences. For instance, people with high interoceptive sensitivity may be more likely to emphasize information about high/low arousal in their emotional self-reports (Barrett, Quigley, Bliss-Moreau, & Aronson, 2004). Sensitivity and awareness of interoceptive information is fundamental to many other forms of cognition as well.

**My question is whether we can improve people's interceptive awareness/accuracy with some sort of intervention (e.g., biofeedback) and whether this improvement might predict other adaptive outcomes.**

# Answer
## Interoceptive awareness and accuracy

Interoceptive awareness and accuracy are sometimes used interchangeably, but can also refer to two different things: awareness to the tendency to attend to interoception measured by self-report, and accuracy to the actual accuracy with which one does so (Chentsova-Dutton and Dzokoto, 2014). For example, a cross-cultural study involving West African and European-American found that "West Africans showed higher levels of interoceptive awareness, but lower levels of interoceptive accuracy than European Americans" (Ceunen, Van Diest and Vlaeyen, 2013).

## Heartbeat perception training

There have been some recent attempts to produce improvements in interoceptive awareness and accuracy. Schaefer, Egloff, Gerlach and Witthöft (2014) gave 29 patients with somatoform disorders heartbeat perception training, and reported that the training selectively improved interoceptive accuracy in patients with low health anxiety, as well as improvements in symptoms.

## Mindfulness

Silverstein, Brown, Roth and Britton (2011) also found that mindfulness training produced a statistically significant benefit in speed of interoceptive awareness, and that this improvement was associated with improvements in attentional, self-judgmental, and clinical factors of female sexual dysfunction. They reported the following about increased interoceptive awareness:

> Women who participated in the meditation training became significantly faster at registering their physiological responses (interoceptive awareness) to sexual stimuli compared with active controls (F(1,28) = 5.45, *p* = .03, $η\_{p}^2$ = 0.15).

Another recent study of experienced meditation practitioners did not report a benefit of meditation on either interoceptive awareness or accuracy, however (Khalsa et al., 2008). Additionally, I am generally skeptical of the benefits of mindfulness on cognitive ability. See Jeromy's answer about the general effect of mindfulness on cognition.

## References
> 3 votes

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Tags: emotion, interoception, biofeedback
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# Question
Title: Is Altmann's memory-for-goals model valid for higher-level multitasking?
Altmann's memory-for-goals model models goal-directed cognition in terms of the general memory constructs of activation and associative priming (Altmann 2002). From reading the paper I understand the model predicts response times during very low-level subgoal switching, like intermediate steps when solving a tower of Hanoi.

I have seen this paper being referenced by many multitasking and interruption studies within the field of Human-Computer Interaction (e.g., Adler, 2012). These types of studies are generally interested in more real-world knowledge work, such as interrupted office work by telephone calls where one's attention needs to be directed to the incoming call.

I'm skeptical as to whether this model and implementations of it using ACT-R (Anderson et al. 2004) is applicable to such higher-level knowledge work. Some of its implications seem relevant, like the problem state bottleneck. **Are there any grounds for assuming the two are related?**

## References

Altmann, E. M., & Trafton, J. G. (2002). Memory for goals: An activation-based model. Cognitive science, 26(1), 39-83.
Adler, R. F., & Benbunan-Fich, R. (2012). Juggling on a high wire: Multitasking effects on performance. International Journal of Human-Computer Studies, 70(2), 156-168.
Anderson, J. R., Bothell, D., Byrne, M. D., Douglass, S., Lebiere, C., & Qin, Y. (2004). An integrated theory of the mind. Psychological review, 111(4), 1036.

# Answer
**Short answer:** Altmann's model is hierarchical and allows for "higher-level" goals and "lower-level" goals, but a goal is ultimately a goal―higher level goals are just sets of lower level goals, at least as far as I understand it. Given its ability to predict performance on solid laboratory tasks like the Tower of Hanoi, there is no reason to think that goal-activation/memory-for-goals theory *wouldn't* apply to "higher-level" multitasking.

Altmann's theory does not appear to be *implemented* in ACT-R. The relationship between the two instead appears to be that Altmann borrowed ACT-R's forgetting function for his model.

**Longer answer:** Goal-activation theory relates to real-world work in the sense that real-world work often requires juggling multiple goals. Such higher-level multitasking often requires the worker to temporarily stop working towards a goal in order to pursue another. Goal-activation theory helps explain this by accounting for this inhibition of the ongoing task and shifting to the new task. In order to do so, the worker must encode, store and retrieve different goals from memory depending on contextual salience and retrieval history.

The paper Jeff quotes in his comment, by Trafton, Altmann, Brock & Mintz (2002), proposed two mechanisms for how different goals reach the top of the goal pile and actually become *activated*: prospective goal encoding and retrospective rehearsal. Both rely on the effect of retrieval practice, and possibly (but not explicitly stated) retrieval-induced forgetting.

Participants were either interrupted during a task with no warning or an 8-second warning prior to interruption. They found that participants in the warning condition were able to improve their responses to interruption. This suggests that the goal-activation model's ability to explain inhibitory performance on Tower of Hanoi can be generalized to real world tasks.

(As an aside: Methodologically speaking, the Tower of Hanoi in particular is a generally well validated task for measuring executive inhibition across task domains. It has an impressive clinical/practical empirical pedigree that is readily available by, for instance, forward searching Miyake et al. (2000). I don't see why performance on a Tower of Hanoi task would be considered "low-level" or meaningfully different from "real-world knowledge work," at least in terms of aspects that might relate to goal-activation.)

## References
> 2 votes

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Tags: cognitive-psychology, cognitive-modeling, hci
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# Question
Title: Is fear of parasites an explanation for trypophobia?
Trypophobia is the

> alleged pathological fear of objects with irregular patterns of holes, such as beehives, ant hills and lotus seed heads.

I find some sample pictures that relevant to trypophobia sickening, because they remind me of a human flesh infested with some parasites.

Thus, I wondered whether there can be an evolutionary formed reflex making people feel disgust when they see a certain geometrical patterns, to prevent them from being infested.

Does this sound like a sensible explanation for the reasons behind trypophobia?

# Answer
> 5 votes
Intuitively, I would also see disgust or fear of contamination as a plausible pathway. However, the explanation that has been discussed in the literature is that trypophobia-eliciting stimuli have basic visual characteristics that are also found in highly poisonous animals (Cole & Wilkins, 2013). Quoting their abstract:

> Phobias are usually described as irrational and persistent fears of certain objects or situations, and causes of such fears are difficult to identify. We describe an unusual but common phobia (trypophobia), hitherto unreported in the scientific literature, in which sufferers are averse to images of holes. We performed a spectral analysis on a variety of images that induce trypophobia and found that the stimuli had a spectral composition typically associated with uncomfortable visual images, namely, **high-contrast energy at midrange spatial frequencies**. Critically, we found that **a range of potentially dangerous animals also possess this spectral characteristic**. We argue that although sufferers are not conscious of the association, the phobia arises in part because the inducing stimuli share basic visual characteristics with dangerous organisms, characteristics that are low level and easily computed, and therefore facilitate a rapid nonconscious response.

(emphasis added)

There is not much research on this phobia though, so it may still be that contamination fears are also a contributing factor.

**Source**

Cole, G. G., & Wilkins, A. J. (2013). Fear of holes. Psychological Science, 24, 1980–1985. doi:10.1177/0956797613484937

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Tags: abnormal-psychology, clinical-psychology, anxiety, phobia
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# Question
Title: Comparative functional neuroanatomy: humans & octopodes
Cephalopod brains are toroidal (high surface area to volume ratios!), with the esophagus passing through the, uh, donut hole; octopodes are very intelligent, particularly spatially.

**Where can I find more information on the functional and anatomical comparisons between human and cephalopod brains, and its consequences for the cognitive abilities of both?** Specifically questions like

* How does the functional neuroanatomy of the cephalopod compare to human functional neuroanatomy?
* How does cortical organization (both perpendicular to the surface and across the surface) between cephalopods and humans compare?
* How do human spatial cognitive abilities differ from those of the octopus? (Somewhat akin to how the pigeon's object recognition capabilities are less dependent on canonical views of familiar objects than the human system.)

Bonus points for answer materials that are aimed at those with a knowledge of other neural systems, particularly human.

# Answer
> 4 votes
You could start with Hochner's papers, like this one:

Hochner, B., Shomrat, T., & Fiorito, G. (2006). The octopus: a model for a comparative analysis of the evolution of learning and memory mechanisms. *The Biological Bulletin*, 210(3), 308-317. http://www.biolbull.org/content/210/3/308.full

As far as I know, he is a world expert.

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Tags: neuroscience, animal-cognition, neuroanatomy, spatial-cognition, comparative-cognition
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# Question
Title: Does a short nap improve learning efficiency?
When one attempts to learn a new skill (e.g., play a guitar), it is often heard that the first hour of practice is more effective than the second. I have heard some people say that even 10 minutes of practice may be effective when you do so everyday.

On many (non-scientific) websites I have read that taking a little nap of 15-30 minutes during prolonged practice is enough to maintain effective learning. Is this true, or is more sleep required? Or is sleep irrelevant altogether?

# Answer
Naps may help if you are so sleepy that you can't focus in learning/training anymore. More importantly however, even a short sleep gives start for the memory consolidation process. So all the things you learned before the nap, get better shielded against the new conflicting or overlapping information in future. Especially in procedural learning (e.g. fingers on guitar chords), which is slow, gets important boost by a training -\> consolidation -\> training -\> consolidation loop. Deep sleep (slow wave sleep at night) is more important, but already nap with light sleep phases (state II with k-complexes) will help.

You can search research papers for "memory consolidation" and "sleep".
> 3 votes

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Tags: learning, sleep
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# Question
Title: Is there a way to have strangers tag my images?
I would have liked to know what thoughts people get from various images, so that I could trigger targeted thought patterns with images.

An easy way to do this would be if I could find an online service that lets strangers "tag" my images with their own keywords. Especially if I could somehow count votes for each keyword/tag.

Does there exist any kind of service like this? Or does anyone know of a similar approach I could use?

# Answer
> 4 votes
Amazon Mechanical Turk is perfect for something like this. In fact, tagging content is one of their default project types, so you should be able to just load in your images and use their template for tagging.

If you haven't seen it before, MTurk is basically a labor marketplace for very small tasks. It works best for paying people a few cents to complete very short tasks, but it is frequently used to recruit subjects for longer behavioral studies as well.

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Tags: measurement, methodology, experimental-psychology, internet
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# Question
Title: How technical can cognitive science get during a Master's?
Nice to find this resource on the internet, I’m in need of advice from knowledgeable people in the field regarding the choice of CogSci Master’s program.

My situation is that I have an undergraduate degree (like a B.A.) in psychology, a major which I never really enjoyed because:

1. Psychology as a "survey science" is not interesting to me.
2. Theoretically, psychology is a mess, too much "pop science", not enough clarification of the issues.
3. I’m not enough adequate/motivated enough to perform in the kind of work psychologists do in clinical, educational or organizational settings.

Anyway, now that i'm done with undergrad, and I found out about CogSci as a parallel-associated-updated field which deals with psychology from a computational basis. I would like to get in a masters where the training in analytical methods, be it computational modeling, statistical analysis or other kinds, is good enough, to have new professional horizons closer to what a computer scientist does.

My current interests are cognitive robotics, behavioral operations management and cognitive economics through as I said mathematical and other analytical methods, which end up having to with Applied Cognitive Science

Given that during my BA I didn't train myself in mathematics enough, would CogSci help develop the relevant skills and change my career perspectives? What programs would you recommend which are strong in this sense?

# Answer
Cognitive science graduate programs are quite diverse, reflecting the diverse interdisciplinary nature of the field. There will be some mix of psychology, computer science, neuroscience, and possibly philosophy, linguistics, and education. Individual programs differ in the relative proportions of those components, which then determines how much technical/computational background is needed and how much is taught. That said, because many people come to cognitive science from psychology, it is fairly common for first year students to be inclined to computational/quantitative approaches but not necessarily trained in those techniques -- in many cases, that's the point of the graduate program. If you haven't already, I recommend checking out the Cognitive Science Society's Study page.

Regarding career paths, CogSci programs tend to be academically-oriented PhD programs. That is, training students to do basic research and to be professors. Of course, many students choose other paths, but few programs specifically prepare them for those other paths. One exception is the Drexel University Applied Cognitive and Brain Sciences program (full disclosure: I'm faculty in that program). We emphasize quantitative training with classes on computational cognitive modeling (Bayesian and PDP models) and statistical tools beyond the core behavioral science statistical methods (multilevel regression, Bayesian statistics, analysis of neuroimaging data, data mining). Our goal is to prepare students for careers in both academia and industry. The Masters program is based on essentially the same coursework as our PhD program.
> 7 votes

# Answer
So, after doing some more research, I've found some more examples of Cognitive Science being presented from a sort of technical perspective or with a technical emphasis (instead of a "pure science", social science or medical science perspective). They are the following:

http://www.dtu.dk/english/Education/msc/Programmes/mathematical\_modelling\_and\_computation/Focus-areas/Cognitive-Science-and-Technology

The others are the Rensselaer Cognitive Science Dept. in the USA and the Cognitive Science Masters in the Applied Informatics Dept. in Bratislava, Slovakia (can't post more links).

Besides these there are broadly conceived Cognitive Science Depts. which have at least 2 or 3 areas devoted to more technical research or projects like for example Cognitive Science in Osnabrück, Germany or the "Cogmaster" in Paris, France.

I think these are examples of programs that provide professional and technical projection after their studies besides that of an academic career. This for me helps clarify the association between Cognitive Science and Computer Science and its potential, given that this is how this field started and how it differentiates itself from Psychology as the study of the mind and behavior. Cheers!
> 0 votes

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Tags: study-cognitive-sciences
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title: In what ways can neurons fire randomly?

text:
# Question
Title: In what ways can neurons fire randomly?
When developing a model of a biologically-plausible neural network, it is important to know all the circumstances under which neurons can fire. But, I am limiting this question to random firing. In what ways, if any, can neurons fire randomly, i.e., without (or regardless of) presynaptic input?

I'm looking for something like:

> Between 0 and 6 days of age, rat cortical neurons randomly fire at an average rate of once every 30 minutes. The rate decreases to 0 by age 12 days. Reference: *here*

(That's just an example)

In what ways can neurons fire randomly?

# Answer
Answering the question in the manner that you are asking for would require quite an exhaustive list. However, a fundamental concept in all of this is having a "leak" channel.

> NALCN is the only nonselective channel found in the 24-TM channel family and is equally permeable to Na+, K+, and Cs+. \[1\]

The majority of the ions transported by the channel are sodium. This slow influx will have the same effect on voltage over a longer period of time as would a rapid influx, a depolarization of the membrane.

> NALCN is found in all animals studied, from humans to *D. melanogaster*, *C. elegans*, snails, sea urchins, and the placozoan *Trichoplax adhaerens*.

So, it is likely that this channel is conserved in the evolutionary ladder.

> NALCN mutant mice have a severely disrupted respiratory rhythm and die within 24 hours of birth. Brain stem-spinal cord recordings reveal reduced neuronal firing. The TTX- and Cs(+)-resistant background Na(+) leak current is absent in the mutant hippocampal neurons. \[2\]

This addresses your other question, this leakage makes the membrane voltage more permissive to initiation of rhythmic discharge and other oscillatory behaviors.

As to whether anything fires "randomly", I would say that neurons can fire with a given distribution \[3\], but this is governed by all the different channels which operate and their conductances (inverse of resistance) rather than just by chance alone. Remember, if a neuron fires randomly, it's not likely to have much effect on a post-synaptic cell unless it's time-locked to a series of other action potentials arriving at the same spot.

> \[1\] Ren, D. (2011). Sodium Leak Channels in Neuronal Excitability and Rhythmic Behaviors. Neuron, 72(6):899-911. http://www.ncbi.nlm.nih.gov/pubmed/22196327
>
> \[2\] Lu B, Su Y, et al (2007). The neuronal channel NALCN contributes resting sodium permeability and is required for normal respiratory rhythm. Cell, 129(2):371-83. http://www.ncbi.nlm.nih.gov/pubmed/17448995
>
> \[3\] Webb TJ, Rolls ET, Deco G, Feng J. (2011) Noise in attractor networks in the brain produced by graded firing rate representations. PLoS One, 6(9):e23630. Free PDF
> 17 votes

# Answer
Closely related to random firing:

Neurotransmitter-filled vesicles are released not only *en masse* when a neuron fires but also **individually at random intervals**. Nobel laureate Bernard Katz, who studied NMJs, observed:

> In the absence of any form of stimulation, the end-plate region of the muscle fibre is not completely at rest, but displays electric activity in the form of discrete, randomly recurring *miniature* end-plate potentials.

For chemical synapses in general (not just NMJs), such potentials are known as miniature excitatory postsynaptic potentials.

### References
> 11 votes

# Answer
First, you need to keep in mind that what one would consider "random" might not be "random" for another person. On one extreme, some scientists believe the brain is operating essentially deterministically (thermal/quantum noise is too small), that is, if you know the "precise" state of the brain and its environment, you can predict its future states for a very long time. Regardless of the truth of that statement, neural signals are effectively random due to our lack of knowledge.

Now, you specifically asked if a neuron can make random responses regardless of synaptic input. Yes, it can.

1. There have been many controlled current injections to neurons. For example, in the figure below, **repeated trials with exactly same current step show slight differences in the spike trains**.

2. Thermal fluctuations of channels can cause spontaneous fluctuations in the membrane potential.
3. There are spontaneously firing neurons (no synaptic input necessary). (See https://biology.stackexchange.com/a/15259/460)

Figure from: Mainen, Z. F. and Sejnowski, T. J. (1995). **Reliability of spike timing in neocortical neurons**. *Science*, 268(5216):1503-1506.
> 5 votes

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Tags: neuroscience, theoretical-neuroscience
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# Question
Title: Are there any circumstances where schizophrenia or bipolar disorder are not lifelong?
It is known that psychiatric disorders such as schizophrenia and bipolar I, and bipolar II are for life, and require long term treatment (lifelong).

Is this always the case?

The answer could include reference to *any* disorder, even those not listed in the DSM, *say bipolar III, bipolar IV, bipolar V, etc.* This refers to what is known as *bipolar spectrum disorder*.

# Answer
According to this systemic review (:the most objective kind of evidence come from reviews of studies not primary sources:) 1 in 7 schizophrenia patients met criteria for recovery.

Source: http://www.medscape.com/viewarticle/814844

> # A Systematic Review and Meta-analysis of Recovery in Schizophrenia:
>
> **Conclusions:** Based on the best available data, approximately, 1 in 7 individuals with schizophrenia met our criteria for recovery. Despite major changes in treatment options in recent decades, the proportion of recovered cases has not increased. http://www.medscape.com/viewarticle/814844
> 3 votes

# Answer
The current understanding, I believe, is that symptomatic psychiatric disorders may or may not be lifelong according to many factors, but that the susceptibility to them probably is lifelong. Some examples. . .

* Substance-induced psychosis (which is pretty much what it sounds like) is often though not always temporary.
* Certain types and locations of brain tumors may cause psychotic symptoms, which may or may not reverse on treatment. Afr Health Sci. Dec 2004; 4(3): 190–194.
* Major depressive disorder has a highly variable course, and may reoccur or may not. N Engl J Med 2008; 358:55-68. DOI: 10.1056/NEJMra073096
> 4 votes

# Answer
Schizophrenia has no cure, which means you cannot "force" it to stop. However, not every case is lifelong by nature.

Information on schizophrenia prognosis: http://en.wikipedia.org/wiki/Prognosis\_of\_schizophrenia

> "A clinical study using strict recovery criteria (concurrent remission of positive and negative symptoms and adequate social and vocational functioning continuously for two years) found a recovery rate of 14% within the first five years.\[17\] A 5-year community study found that 62% showed overall improvement on a composite measure of clinical and functional outcomes.\[18\]"

Some tellings from people who have come through: http://www.topix.com/forum/health/schizophrenia/TL09TM53OI68I1IVI
> 3 votes

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Tags: clinical-psychology, psychopharmacology, schizophrenia, bipolar-disorder
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# Question
Title: Modern treatments of Alan Turing's B-type neural networks
In the cognitive sciences Alan Turing is best known for launching AI with his *Computing machinery and intelligence* (1950). However, this was not his first contribution to the cognitive sciences, in his unpublished 1948 technical report *Intelligence Machinery* he foresaw connectionism with his B-type neural networks.

The model is a recurrent neural network that is wired at random, and synchronized by a global clock. The neurons are two input $\mathrm{NAND}$-gates. The connections have one of two states: they either forward their signal perfectly ($0 \mapsto 0$ and $1 \mapsto 1$), or replace it by $1$ ($0 \mapsto 1$ and $1 \mapsto 1$). The learning algorithm adjusts the states of the connections.

Unfortunately, the director of the National Physical Laboratory rejected Turing's work and it was not published until significantly after Turing's death. The original manuscript, though predates Hebbian learning (1949) and Rosenblatt's perceptrons (1957; and they weren't as sophisticated, only doing feedforward as opposed to recurrent).

**Was Turing's B-type neural networks are the earliest neural-like models of computations capable of learning?**

Although by modern standard Turing's approach is dated, and has been supplanted by more realistic and general treatements (for instance ones that incorporate dynamic Hebbian updating on weighted connections without a need for central clock synchronization). **When did the state of connectionism first surpasss Turing's B-type neural networks?** **Is there modern treatments of B-type neural networks and their learning abilities?**

---

### Notes

I am interested in this mostly from the historic perspective, and not in how accurate Turing's model was under current interpertations. Although current knowledge would help answer when other models surpassed Turing's.

# Answer
To my knowledge, with respect to the context of the question, the **first neural-like model of computations capable of learning** – or, for that matter, computational model of neural processing and learning – has been put forward in McCulloch/Pitts (1943), as is also acknowledged in some of the texts about Turing's unorganized machines (*›A-/B-type neural networks‹*). Turing does not refer to this paper in his 1948 report, however, constituting a central reference for Rosenblatt's perceptrons, the McCulloch/Pitts paper is also regularly ignored in historic accounts of connectionism.

Turing's original unorganized machines are generally recognized as having some limitations with regard to certain logical operations such as XOR (cf. e.g. Teuscher/Sanchez 2001). In this respect (which for brevity may just be called one of historical narrative) they are similar to the perceptron. Thus, it seems safe to assume that at least **connectionism surpassed B-type unorganized machines** when it was shown how to implement such functions (e.g. in the infamous Minsky/Papert 1969 – mind that this does not necessarily imply a general logical shortcoming of the original models).

The relatively few **papers that have addressed the topic over the last 20 years** have indeed expressed the observation that Turings unorganized machines have been largely neglected and thus constitute an interesting topic for more detailed analysis – but see Teuscher (2002) for a monograph on the subject.

---

• Boccato, L., Soares, E. S., Fernandes, M. M. L. P., Soriano, D. C., & Attux, R. (2011). Unorganized Machines: From Turing’s Ideas to Modern Connectionist Approaches. *International Journal of Natural Computing Research*, 2(4).

• Copeland, B. J., & Proudfoot, D. (1996). On Alan Turing's anticipation of connectionism. *Synthese*, 108(3), 361–377. doi: 10.1007/BF00413694

• Copeland, B. J., & Proudfoot, D. (1999). Alan Turing's Forgotten Ideas in Computer Science. *Scientific American*(280), 99–103.

• McCulloch, W. S., & Pitts, W. (1943). A Logical Calculus of the Ideas Immanent in Nervous Activity. *Bulletin of Mathematical Biophysics*, 5, 115–133.

• Minsky, M., & Papert, S. (1969). *Perceptrons. An Introduction to Computational Geometry*. Cambridge, Mass.: MIT Press.

• Teuscher, C. (2002). *Turing’s Connectionism. An Investigation of Neural Network Architectures*. London: Springer-Verlag.

• Teuscher, C., & Sanchez, E. (2001). A Revival of Turing’s Forgotten Connectionist Ideas: Exploring Unorganized Machines. In R. M. French & J. P. Sougné (Eds.), *Connectionist Models of Learning, Development and Evolution* (pp. 153–162): Springer London.

• Webster, C. S. (2012). Alan Turing’s unorganized machines and artificial neural networks: his remarkable early work and future possibilities. *Evolutionary Intelligence*, 5(1), 35-43. doi: 10.1007/s12065-011-0060-5
> 10 votes

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Tags: computational-modeling, neural-network, connectionism
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# Question
Title: Why is it that only humans commit suicide?
Many animals do 'brave' things to protect their children or family, and some male spiders sacrifice themselves so that they can impregnate the females.

However, humans commit suicide without necessarily any intention to help their kin. Why?

# Answer
> 8 votes
Such behavior does exist in the wider animal world, not just in humans.

See the Wikipedia page on Animal Suicide, particularly the section titled "Suicidal behavior".
(if you have done any preliminary research on this, be aware that your question doesn't reflect it).

There are a number of linked studies in that section, some of which may give you good or relevant information.

What it comes down to is twofold:

1. We can't reasonably say that animals are pursuing suicidal behavior for similar reasons that humans do, as we don't have a good enough view into the cognitions of other animals, and
2. We still don't fully understand the etiology of suicide (much less depression!) in humans, either, which confounds the entire issue.

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Tags: abnormal-psychology, animal-cognition
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# Question
Title: Are any kinds of behavior proved to correlate with testosterone levels?
Are any kinds of behavior proved to correlate with testosterone levels? Any studies done on this? Any indications of such correlations?

# Answer
> 5 votes
> "There was a significantly **higher level of plasma testosterone in the aggressive group** as compared with the nonaggressive group or with the other two groups combined. **The socially dominant group also had a significantly higher level of testosterone** than the nonaggressive group." http://journals.lww.com/psychosomaticmedicine/Abstract/1974/11000/Plasma\_Testosterone\__Correlation\_with\_Aggressive.2.aspx

-

> "Analysis of archival data from 4,462 U.S. military veterans supported the first hypothesis: **Testosterone was correlated with a variety of antisocial behaviors** among all individuals." http://pss.sagepub.com/content/1/3/209.short

-

> "Plasma testosterone levels did not differ in fighting and nonfighting individuals. Although there were significant correlations between psychologic tests, the test scales did not correlate either with plasma testosterone or with fighting behavior. The 10 prisoners with histories of more violent and aggressive crimes in adolescence had a significantly higher level of testosterone than the 11 prisoners without such a history. An hypothesis is presented that **within a population that is predisposed by virtue of social factors to develop antisocial behaviors, levels of testosterone may be an important additional factor in placing individuals at risk to commit more aggressive crimes in adolescence**." http://journals.lww.com/psychosomaticmedicine/Abstract/1972/07000/Assessment\_of\_Aggressive\_Behavior\_and\_Plasma.6.aspx

-

> "Statistically **significant changes in MMPI–2 scale scores were found at 3-month follow-up after initiating testosterone treatment relative to baseline for transgender men** compared with female controls (female template): reductions in Hypochondria (p \< .05), Depression (p \< .05), Hysteria (p \< .05), and Paranoia (p \< .01); and increases in Masculinity–Femininity scores (p \< .01)." http://psycnet.apa.org/psycinfo/2014-32641-001/

-

> Baron-Cohen and his colleagues recently found that **giving testosterone to women decreases their ability to empathize**, particularly among women whose bodies show evidence that they were exposed to higher levels of testosterone in utero. And **previous research has linked high levels of testosterone in the womb to autistic traits**. (Interestingly, in-utero exposure to testosterone can be estimated by looking at the ratio between the length of the ring finger and index finger.) http://healthland.time.com/2011/05/18/study-why-some-transgendered-people-have-higher-levels-of-autistic-traits/

\-

Contrary to what many believe:

> No direct associations were found between testosterone and solitary or dyadic sexual desire. http://www.eje-online.org/content/165/2/331.full.pdf

**Some transgender people say they have changes parts of their personality, but I've found no studies to prove this.**

> "Chris Edwards, a trans advertising executive, says that **post-transition, he was given greater levels of responsibility**—but he thinks it’s because the testosterone he took changed his behavior. **He became less timid and more outspoken—and was seen, at work, as more of a leader**. Indeed, *some suggest that transmen might experience these workplace benefits partly because, post-transition, they are happier and more comfortable, and that this confidence leads to greater workplace success. But if that’s the case, one would expect that transwomen, armed with this same newfound confidence, would see benefits. The opposite seems to be true*. " http://www.newrepublic.com/article/119239/transgender-people-can-explain-why-women-dont-advance-work

-

> "Now that we’re roughly **two years into the process there has been a dramatic change in personality**. This was expected, I knew there would be highs and lows because the process takes a huge toll. However now she just treats everyone like garbage. The whole world absolutely has to revolve around her. No one can be right unless it happens to be from her prospective. She exemplifies all of the negative stereotypes of both transgender people and women. **The personality change went from laid back punk rocker to being what I can only sum up as a stuck up diva**." https://answers.yahoo.com/question/index?qid=20100430043917AAYcyD8

Note that stories like the one above may have several possible causes, including identity changes (suddenly seeing oneself as a different gender), depression (generally bad mood) or placebo.

# Answer
> 2 votes
This is an illness, not a behavior, but schizophrenia is known to be correlated with high testosterone levels. Of course, as the article I linked to itself states:

> “However, as with most endocrine and mental illnesses, schizophrenia is multifaceted (genetic, environmental etc.)...”

Of course this is just one example, but I always thought the schizophrenia-testosterone link was interesting.

# Answer
> 0 votes
I'm not sure this is what you asked for but the guy in this video will tell about the study conducted on how **behaviour can affect the testosterone production**. He'll say that by doing the *power pose* (acting like you're the boss) for *2 mins will increase the testosterone by 20%* and *reduce cortisol levels*

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Tags: behavior, testosterone, correlation
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title: How similar are the brains of twins?

text:
# Question
Title: How similar are the brains of twins?
I am currently reading undergraduate essays on biological dysfunction and schizophrenia. The students put a lot of weight in the fact that studies of monozygotic twins show only a 50% rate of concordance. How similar, in terms of anatomical structure and connectivity, are the brains of monozygotic twins?

# Answer
> 5 votes
Biondi et al. (1998) compared MR images of monozygotic twins and found that while the brains of monozygotic twins are not identical, they are similar. Relevant for understanding the concordance rate of schizophrenia in monozygotic twins, Suddath et al. (1990) examined MR images of monozygotic twins who where discordant for schizophrenia. They found that the schizophrenic twin had enlarge cerebral ventricles and subtle anatomical abnormalities although the study seems to lack a control group of either both schizophrenic, both normal, or discordant on some other disease.

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Tags: neuroscience, developmental-psychology, neuroanatomy, nature-nurture, twin-study
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