# Question
Title: If time travel were possible, would travelling back in time result in memory loss?
Suppose it is possible to travel back in time. If Bob traveled back in time, wouldn't he lose the memory of what happened since his neurons are also traveling back in time? In other words, traveling back in time would feel like the present moment. Consider this thought experiment:

Bob eats pizza at 12 PM.

Bob plays tennis at 2 PM.

Bob travels back in time to 12 PM.

Would Bob lose the memory of him playing tennis at 2 PM and essentially treat 12 PM as an ordinary experience?

# Answer
This is a tricky topic and my answer will be clearly speculative. I will say that this is also largely a matter about metaphysical allowances and involves personal identity implications. Assuming that time travel is physically possible, we need to make assumptions around how time is interpreted within the time travel journey.

**Scenario 1: Time travel based on external time and fatalism**

Lewis (1976) distinguishes between two interpretations of time, i.e. *personal* and *external* time:

> Instead I reply by distinguishing time itself, external time as I shall also call it, from the personal time of a particular time traveler: roughly, that which is measured by his wristwatch. His journey takes an hour of his personal time, let us say; his wristwatch reads an hour later at arrival than at departure. But the arrival is more than an hour after the departure in external time, if he travels toward the future; or the arrival is before the departure in external time (or less than an hour after), if he travels toward the past.

Should Bob decide to travel back to 12 PM relative to *external time*, we can speculate implications on his continuity of personal identity. Le Poidevin (2005) elaborates on discontinuous movement through time:

> ... it seems that discontinuous movement is possible: one can move from A to B without occupying places in between.

If so, it seems probable that Bob could lose his memory of playing tennis at 2 PM if discontinuous movement is allowed. Based on external time, he is in fact moving back 2 hours, however, implied is the suggestion that he won't be psychologically continuous and thus, won't remember that experience. Whether he will treat 12 PM as an ordinary experience or a completely new experience depends on how we interpret causal relations between past and present.

Fatalism suggests that we are unable to deliberate about the future or change it (Taylor, 1962). It is logically and physically impossible to change any events preceding the time travel point. From a fatalist viewpoint, Bob would experience all those events from A to B as they had occurred.

**Scenario 2: Time travel based on personal time**

The other scenario presupposes that time travel is continuous from the time traveller's *personal time* in which the person is psychologically continuous - there is no disconnect between the stages of the psychological and physical continuum when travelling time. If so, it may be possible for Bob to travel back to 12 PM, re-experience eating the pizza while his memory of playing tennis remain intact. Although time travel isn't physically possible, we can still project ourselves backwards in time and recall events (Suddendorf & Corballis, 2007).

Since this scenario doesn't sever the continuity of Bob's personal identity, it seems probable that he would still remember the experience of playing tennis at 2 PM while able to freely experience new events (given that fatalism is rejected) thereafter and the mere possibilities that follow.

**References**

* Lewis, D. (1976). The paradoxes of time travel. American Philosophical Quarterly, 13(2), 145-152
* Le Poidevin, R. (2005). The Cheshire Cat problem and other spatial obstacles to backwards time travel. The Monist, 88(3), 336-352
* Suddendorf, T. & Corballis, M.C. (2007). The evolution of foresight: What is mental time travel, and is it unique to humans? Behavioral and Brain Sciences, 30, 229-351
> 1 votes

# Answer
An analogy would be, if the person ate lunch at

Bob eats pizza at 12 PM.

Bob shaves off moustache at 12.30 PM.

Bob plays tennis at 2 PM.

Bob travels back in time to 12 PM.

Would Bob have his moustache back? If not, then he would retain his memory. As the changes are comparable. Both physical.

As memory requires LTP of the brain, which means there are physical changes to the brain, one would assume that the act of time travel, would not alter the person's brain chemistry (their rationality perhaps). As the person's physical body would be transported in space and time, not transmuted.

As a Doctor Who fan, during the doctor's travels, he has full memory of his previous experiences (unless there is another reason, not pertaining to the time travel itself, that has caused him to not recall who is is).

My questions would be the following:

Bob eats pizza at 12 PM.

Bob plays tennis at 2 PM.

Bob travels back in time to 12 PM.

Which psychotic illness is Bob most likely to have?
> 1 votes

# Answer
The answer presumably depends on how you conceptualise the experience of the time traveller relative to the time travel. In most movies the world and most other people in the world are just restored to the original time, but the time traveller is somehow immune to such effects.

For this version of time travel to be true and consistent with neuroscientific theories of the mind-body relationship, then presumably the brain of the time traveller is not altered by time travel, or at least is not altered in such a way to restore the brain to the state it was in at the time of return. Thus, **memories of the future would be retained when going back in time**.

In fact, if the mind of the time traveller was restored to the returned time, then this could result in non-existence if you travelled back further than when you were born. It would also seem inconsistent with the possibility of going back in time but being in the same location that you initiated the time travel.

*You might also wish to see what answers you get on https://scifi.stackexchange.com/*
> 0 votes

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Tags: time
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title: Differences between anger and rage

text:
# Question
Title: Differences between anger and rage
Can rage be considered a subset of anger or possibly a separate neurobiological process.

What are the neurobiological, evolutionary and psychological differences between anger and rage?

In more detail an examination of the similarities and differences between anger and rage, their roles and purposes for us as a species.

* what is the difference in neurochemistry
* what are the evolutionary advantages of these states.
* how do these two neurochemical processes assist us psychologically with regard to survival of our species

An examination of misplaced anger or rage, as possibly less useful states, although perhaps not entirely redundant, and possible pathology arising from this may or may not be included within answers.

# Answer
> 2 votes
The American Psychological Association appears to view this emotion as a continuum of intensity, whith *annoyance* at the mild and *rage* at the extreme end.

http://www.apa.org/topics/anger/control.aspx

Excessive anger and rage might be caused by suppressing milder forms of anger until this repression becomes unbearable and "the pot cooks over". *Psychology Today* calls anger a "corrosive emotion": it eats away at you, if you don't express it.

http://www.psychologytoday.com/basics/anger

The continuum and boiling-over idea of anger are nicely summed up in this paragraph of another *Psychology Today* article:

> Irritation, frustration, anger, rage: these are all forms of anger. And they are feelings first. But when a person’s rage becomes behavior even before thought has a chance to plug in, it is usually because of one of two reasons: 1) it’s been repressed for a long time, and when someone drops the proverbial straw, it explodes; 2) it works for manipulative purposes.

http://www.psychologytoday.com/blog/traversing-the-inner-terrain/201205/is-rage-choice

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Tags: emotion
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title: what is the reptile brain?

text:
# Question
Title: what is the reptile brain?
As a Carl Sagan fan, I remember (in Cosmos TV shoe) "territoriality, aggression and ritual" are products of the reptile brain while higher-level stuff like loyalty, planning for future are mammalian, which implies different brain regions for each functions.

Even Sheldon Cooper has something to say about this:

> Penny’s emotional responses originate from the primitive portion of the brain known as the Amygdala, while speech is centred in the much more recently developed Neocortex. The former can **easily overpower** the latter giving scientific credence to the notion of being rendered speechless.

And said by on-screen and off-screen neuroscientist and science consultant Mayim Bialik:

> So says your prefrontal cortex. But meanwhile, the limbic system of your brain is calculating that if another woman is attracted to Leonard, it must be because he’s desirable.

---

It implies that the brain is composed of three parts, with vast differences in development, can overpower each other and process stimuli independently.

What exactly is the reptile brain and do modern theories prove such a concept?

# Answer
> 12 votes
The reptilian brain is the oldest part of the triune brain. And the triune brain is a unified account of brain function and brain evolution.

The story goes like this. The brain can be divided into three sections:

* The reptilian brain, named so because it encompasses structures that did not change much from reptile to man. It includes the basal ganglia and cerebellum, and controls pretty much everything that a reptile can do: breathing, walking, appetite, sensation, simple motor reactions to the environment, etc.
* The mammalian brain (sometimes called paleomammalian), which encompasses structures that are unique to mammals but similar across mammalian species. These structures belong to the limbic system and are dedicated to processing emotion and memory. Anything your cat can do, should be either in the reptilian or the mammalian brain. Anything it can't do, is in the third part of the triune brain.
* The neocortex, found in primates, which is involved in higher order functions such as language.

Now, this is an oversimplification both structurally and functionally. For example, birds don't fit this theory very well because they don't have much of a limbic system, but do have some impressive problem solving skills. And functionally, these functions are interrelated in man, who can, for example, experience moral disgust which bridges higher-order and emotional functions. This is why the triune brain is the kind of thing you would find in an undergraduate psychology textbook, but it's not the kind of thing neuroscientists talk about among themselves.

# Answer
> 3 votes
I think the treatment of the “Reptile Brain's” power given by Big Bang really sells it short. Your question immediately brought to my mind a 2009 profile by the *Washington Post's* Gene Weingarten of parents who leave their children in the car to die, all by accident.

It's a long and difficult read, and it took me quite some time to dig it up again since I had forgotten the publication, the author, and the title: but it comes highly recommended from me (read “Fatal Distraction” on washingtonpost.com)

The first page that speaks directly to your question is this one, making reference to the basal ganglia in the brain. A brief excerpt:

> Ordinarily, says \[University of South Florida Cognitive Neuroscience Professor David\] Diamond, this delegation of duty \[between the so-called reptile brain and higher-order brain function\] “works beautifully, like a symphony. But sometimes, it turns into the '1812 Overture.' The cannons take over and overwhelm.”

At a risk of doing a disservice by gross oversimplification of a fascinating and complex topic: the main thrust of the article's insight into cognition is that in rare circumstances, intelligent, emotionally healthy, and responsible parents may find themselves in circumstances where their basal ganglia take over their brain to such a great extent that they are capable of forgetting that their own children exist.

So if the reptile brain has such potential for destruction, albeit rarely to such a great extent, what is its purpose? Clearly in the majority of cases its functioning is very beautiful. When you walk you do not have to think analytically and poetically about every step you take. Your basal ganglia take care of this for you. This is Sagan's “ritual” reference.

If you need an emotional reason to accept that the reptile brain is real, read the Washington Post article. It'll stick with you. If you have more questions about the modern theories underpinning its machanisms, Dr. Diamond is not hard to get a hold of—he lists his contact information here.

# Answer
> 2 votes
The quote by Sheldon from Big Bang Theory is misguided, as the limbic system is not part of the "reptilian brain", it is part of the next development, the paleomammalian complex.

> The Reptilian Complex
>
> The R-complex consists of the brain stem and the cerebellum. Its purpose is closely related to actual physical survival and maintenance of the body. The cerebellum orchestrates movement. Digestion, reproduction, circulation, breathing, and the execution of the "fight or flight" response in stress are all housed in the brain stem. Because the reptilian brain is primarily concerned with physical survival, the behaviors it governs have much in common with the survival behaviors of animals. It plays a crucial role in establishing home territory, reproduction and social dominance. The overriding characteristics of R-complex behaviors are that they are automatic, have a ritualistic quality, and are highly resistant to change.
>
> The Limbic System
>
> The limbic system, the second brain to evolve, houses the primary centers of emotion. It includes the amygdala, which is important in the association of events with emotion, and the hippocampus, which is active in converting information into long term memory and in memory recall. Repeated use of specialized nerve networks in the hippocampus enhances memory storage, so this structure is involved in learning from both commonplace experiences and deliberate study. However, it is not necessary to retain every bit of information one learns. Some neuroscientists believe that the hippocampus helps select which memories are stored, perhaps by attaching an "emotion marker" to some events so that they are likely to be recalled. The amygdala comes into play in situations that arouse feelings such as fear, pity, anger, or outrage. Damage to the amygdala can abolish an emotion-charged memory. Because the limbic system links emotions with behavior, it serves to inhibit the R-complex and its preference for ritualistic, habitual ways of responding.
>
> The limbic system is also involved in primal activities related to food and sex, particularly having to do with our sense of smell and bonding needs, and activities related to expression and mediation of emotions and feelings, including emotions linked to attachment. These protective, loving feelings become increasingly complex as the limbic system and the neocortex link up.
>
> The Neocortex
>
> Also called the cerebral cortex, the neocortex constitutes five-sixths of the human brain. It is the outer portion of our brain, and is approximately the size of a newspaper page crumpled together. The neocortex makes language, including speech and writing possible. It renders logical and formal operational thinking possible and allows us to see ahead and plan for the future. The neocortex also contains two specialized regions, one dedicated to voluntary movement and one to processing sensory information.

The Triune Brain Theory is a cross-species evolutionary study with the developmental processes underlying them (I borrowed a line from <sub>(1)</sub> to use as a definition, as I thought it summed it up well). As mentioned in other answers, it is an oversimplification and doesn't match work across all species.

As opposed to the study of Embryology.

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References:

(1) Mammalian Brain Evolution
Weisbecker
Morphological Evo-Devo Group

Neural System Development
UNSW Embryology

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Tags: evolution, brain-development
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# Question
Title: What is the psychological basis of "survivor's guilt"?
**Context**

I have just been watching a documentary about survivors of the Japanese earthquake and tsunami of March 2011. Specifically the interviews with ordinary residents of the towns affected.

One thing came through time and again was the notion that was best stated by a friend of mine\*- a volunteer firefighter on duty in one of the affected towns on the day of the tsunami:

> what gives me the right to survive, when so many others died?

**Question**

Obviously, this doesn't just occur in Japan, it seems to happen a lot, where people seem to feel guilty to have survived and feel a sense of responsibility for those who perished. What is the psychological basis behind this?

Are there any studies that have addressed this?

**Side notes**

I lived in Japan for 4 years and have many friends from the affected area, this friend of mine was and is still inconsolable that he, in his own mind, could not save more people.

# Answer
**1. Psychological basis of survivor guilt**

**Psychosocial and evolutionary perspective on survivor guilt**

Survivor guilt may be a psychological response that is associated with depression. Loss of a beloved one, which constitutes a psychosocial attachment, can precipitate a proneness towards experiencing survivor guilt. In clinical samples, the clinically depressed tend to suffer from pathogenic cognitions in which they view themselves as harmful to others are an effect of feeling guilty from surviving a beloved one's death (O'Connor et al., 2002). In that regard, we can hypothesise that survivor guilt is probably a self-protective mechanism involving self-denunciation to combat guilt about surviving a beloved one's death.

> Tendency toward self-reproach which death invariably leaves among the survivors (Freud, 1987, cited in Ernest Jones, 1960)

Survivor guilt could have *evolutionary roots* as well: survivor guilt may be a product of evolutionary pressures with living in small groups as a means to promote social organisation (O'Connor et al., 2002). The loss of an individual within these close socially-knit arrangements creates dysfunction and survivor guilt is an evolutionary means to understanding the changes experienced.

**Existential crises, anxiety and ambivalence**

Drawing from logotherapy, survivor guilt can be understood further from an existential point of view by referring to *existential dynamics* (Tate et al., 2012):

> Mental health is based on a certain amount of tension \[or existential dynamics\], the tension between what one has already achieved and what one still ought to accomplish, or the gap between what one is and what one should become. (p. 104)

Survivor guilt may be the tension created between an individual's past experiences and future possibilities. Past experiences such as traumatic events create tension with an individual understanding his or her existence compared to future potentialities. A person narrowly escaping death may physically survive the traumatic experience but in the present moment, they experience excessive amounts of worry about why they are here and what the future holds. This cognitive dichotomy of being shameful about the past and fearful of the future can lead to survivor guilt.

**2. Studies on the psychological basis of survivor guilt**

**Post-traumatic stress disorder (PTSD), cognitive distortions and survivor guilt**

Jones and Okulate (2006) conducted a study on the relationship between PTSD and survivor guilt by administering a questionnaire to 1,131 patients from the 68 Nigerian Army Reference Hospital, Lagos, Nigeria. Of these, 194 (22.09%) met the criteria for current PTSD. Survivor guilt was found in 336 responders (38.26%). The following explanation is given by the authors:

> The reason for the very high rate of survivor guilt may be related to the intra-group identification and cohesiveness that usually develops in combat-effective military units after several years of training together. Unfortunately, loss of men resulting from death or injury in battle is inevitable. For those who survive, witnessing the death of comrades is additional psychosocial stressor to the combat situation itself, and the survivor guilt that may result is understandably very distressing.

**Survivor guilt and chronic illness**

Vamos (1997) provides cases on patients and their experiences of survivor guilt in the face of chronic illness and witnessing other people's illnesses:

> Miss A had visited her frequently and had repeatedly had the experience of trying to bright- en her friend by accounts of shopping expeditions or other excursions, only to feel profoundly guilt-ridden that she could still be enjoying herself when her friend’s life was so limited. Since the death, she had been unable to weep but had found herself compelled to clean both the house and herself repeatedly, and had often wondered whether she should take a ‘break’ from dialysis

**References**

* O’Connor, L.E., Berry, J.W., Weiss, J. & Gilbert, P. (2002). Guilt, fear, submission, and empathy in depression. Journal of Affective Disorders, 71(1), 19-27
* Tate, K.A., Williams, C. & Harden, D. (2012). Finding purpose in pain: Using logotherapy as a method for addressing survivor guilt in first-generation college students. Journal of College Counselling, 2012, 16(1), 79-92
* Okulate, G.T. & Jones, O.B.E. (2006). Post-traumatic stress disorder, survivor guilt and substance use – a study of hospitalised Nigerian army veterans. South African Medical Journal, 96(2), 144-146
* Vamos, M. (1997). Survivor guilt and chronic illness. Australian and New Zealand Journal of Psychiatry 1997, 31, 592-596
> 4 votes

# Answer
**Survivor's Guilt as a medical condition:**

> Are there any studies that have addressed this?

There have been many studies on Survivor's Guilt, in fact Survivor's Guilt or Syndrome; known as concentration camp syndrome or KZ syndrome, was a recognised condition in the DSM, it has been removed and replaced as a symptom of Post Traumatic Stress Disorder.

> ...where people seem to feel guilty to have survived and feel a sense of responsibility for those who perished. What is the psychological basis behind this?

**The concept of social guilt:**

An approach to guilt as a social, rather than individual process. Survivor's guilt is borne from human beings, as a social species, as opposed to being an individual cognitive crisis. It has been demonstrated that guilt serves as a social emotional safety net; ensuring the strong protect the weaker, an important dynamic for the survival of our species.

> Multiple sets of empirical research findings on guilt are reviewed to evaluate the view that guilt should be understood as an essentially social phenomenon that happens between people as much as it happens inside them. Guilt appears to arise from interpersonal transactions (including transgressions and positive inequities) and to vary significantly with the interpersonal context. In particular, guilt patterns appear to be strongest, most common, and most consistent in the context of communal relationships, which are characterized by expectations of mutual concern. Guilt serves various relationship-enhancing functions, including motivating people to treat partners well and avoid transgressions, minimizing inequities and enabling less powerful partners to get their way, and redistributing emotional distress (1)

**Effects of being spared:**

The concept that random as opposed to *deserved* misfortune serves to motivate human beings to strive harder, in accord with an appreciation of their good fortune, at having been spared.

This case refers to the effects of arbitrary redundancies within the workplace, but still illustrates the effects of survivor's guilt.

> This study explored the effects of layoffs on survivors. We assessed subjects' work performance as a function of whether a co-worker had been laid off and the circumstances of that layoff. Consistent with equity theory, subjects worked harder when they believed that a co-worker's dismissal was based on a random process rather than on the relative merits of their and their co-worker's prior performance. Data drawn from questionnaires lent further support to equity theory as an explanation of these results. (2)

**Guilt of being spared:**

In some circumstances guilt may be borne in the individual being saved, at the seeming expense of another individual (this is most clearly defined in the holocaust "Selection Parades"), more subtle in the case of escaping a fire and being unable to rescue another in the process. In other cases it may stem from decisions, which resulted in the loss of a loved one, where the survivor feels the guilt of helping to change the course of that person's life, even though they would have no real knowledge that it would lead to that person's death.

**Exaggerated sense of responsibility:**

It seems the survivors over exaggeration one's human abilities in the face of tragedy. Overlooking our human frailties and utter powerlessness in some situations. Personalising the death of another; as if they could somehow have made a diFference, coupled with the concept, of *why am I more deserving than another?*. The relief of being saved is mixed with guilt at the loss of others and apprehension (possibly a form of dissociation) of it could have been me.

**Disruption of the grief process:**

In cases where people lose close ones, the grief process is disrupted; conflicting emotions surrounding grief can be amplified for example the relief of freedom felt when a young man's father dies and he feels he is an autonomous being; flooded by guilt at feeling this, in the face of such disaster.

**Long term effects:**

This sense of guilt can increase, rather than become ameliorated, over time. The psychological damage from Survivor's Syndrome can be passed onto the next generation.

> The stigma of KZ-syndrome is present in a second generation in different forms: personality disturbances, emotional and/or social immaturity, social disadaptation, higher frequency of neurotic states, divorce, alcoholism, and suicide. The camp stress has left in human nature traces so painful that they cannot disappear when the generation of former prisoners is gone. (4)

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**References:**

* (1) Guilt: An interpersonal approach.
Baumeister, Roy F.; Stillwell, Arlene M.; Heatherton, Todd F.
doi: 10.1037/0033-2909.115.2.243
* (2)Layoffs, Equity Theory, and Work Performance: Further Evidence of the Impact of Survivor Guilt
Joel Brockner et al doi: 10.2307/256193
* (3) The Sense of Guilt within Holocaust Survivors
Ruth Jaffe http://www.jstor.org/stable/4466613
* (4) The evolution of mental disturbances in the concentration camp syndrome (KZ-syndrom).
Ryn Z
> 2 votes

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Tags: social-psychology, emotion
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title: Does music affect heart-rate?

text:
# Question
Title: Does music affect heart-rate?
I've read that the body attempts to match its heart-rate with the tempo of music being listened to.

> Rhythmic Entrainment: 'This refers to a process whereby an emotion is evoked by a piece of music because a powerful, external rhythm in the music influences some internal bodily rhythm of the listener (e.g. heart rate), such that the latter rhythm adjusts toward and eventually 'locks in' to a common periodicity. The adjusted heart rate can then spread to other components of emotion such as feeling, through proprioceptive feedback. This may produce an increased level of arousal in the listener.'

Is this true?

# Answer
> 2 votes
**Music and the autonomic nervous system:**

There have been studies linking the effects of music on well being, by affecting heart rate and blood vessel dilation.

There has been much research linking the effects of music on Autonomic Nervous System (ANS), which affects heart rate. The emotional nature of the music, be it restful or stressful, is linked with changes in the ANS.

> Music emphasis and rhythmic phrases are tracked consistently by physiological variables. Autonomic responses are synchronized with music, which might therefore convey emotions through autonomic arousal during crescendos or rhythmic phrases. (1)

**Effects of music on brain function:**

It has been demonstrated that music can affect brain function through increased arousal or relaxation, depending on the tempo.

> Music induces an arousal effect, predominantly related to the tempo. Slow or meditative music can induce a relaxing effect; relaxation is particularly evident during a pause. Music, especially in trained subjects, may first concentrate attention during faster rhythms, then induce relaxation during pauses or slower rhythms. (2)

**Effects of music on the heart**

Music tempo or style also produces responses to heart rate and blood flow; relaxing or pleasant music producing results equivalent to studies showing the positive effects of laughter on the ANS.

> Music, selected by study participants because it made them feel good and brought them a sense of joy, caused tissue in the inner lining of blood vessels to dilate (or expand) in order to increase blood flow. This healthy response matches what the same researchers found in a 2005 study of laughter. On the other hand, when study volunteers listened to music they perceived as stressful, their blood vessels narrowed, producing a potentially unhealthy response that reduces blood flow. (3)

**Rhythmic entrainment and heartrate:**

Human beings are naturally disposed toward rhythmic entrainment. (4)

There has been some research suggesting that the body will synchronise with musical rhythm. I say this with a disclaimer that this would need to be music played with a regular tempo over a prolonged period, as for the heart beat to synchronise within a mathematical relationship with the music tempo, this would require stability and an absence of other external distraction for the body to achieve this state. Or better put, listening to a variety of music styles, with varying tempos, will affect the ANS, but will not create such a rhythmic coordination between the music and the ANS.

> • Entrainment is the process through which periodic events, i.e. oscillators, become coordinated through interaction. When oscillators come regularly into phase or of beginning their cycles together, way say that they have synchronized.
> • Entrainment in music has been suggested by Juslin et al. (2010) as an emotion mechanism where the music causes an increase in arousal “because the powerful, external rhythm of the music interacts with an internal body rhythm of the listener \*…+, such that the latter rhythm adjusts towards and eventually ‘locks in’ to a common periodicity.” The adjusted body rhythm then spreads through proprioceptive feedback to the subcomponents of emotion such as cognitive, neurophysiological, motivational, expressive, and subjective feelings components. (5)

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References:

* (1) Dynamic Interactions Between Musical, Cardiovascular, and Cerebral Rhythms in Humans
Luciano Bernardi, et al
doi: 10.1161/CIRCULATIONAHA.108.806174
* (2) Cardiovascular, cerebrovascular, and respiratory changes induced by different types of music in musicians and non‐musicians: the importance of silence
L Bernardi, C Porta, and P Sleight
doi: 10.1136/hrt.2005.064600
* (3) Music & Cardiovascular System
University of Maryland Medical Center
* (4) The ecology of entrainment: Foundations of coordinated rhythmic movement
Jessica Phillips-Silver, C. Athena Aktipis, and Gregory A. Bryant
doi: 10.1525/mp.2010.28.1.3
* (5) Rhythm, entrainment and musical emotions
Carolina Labbé & Didier Grandjean
Neuroscience of Emotion and Affective Dynamics (NEAD)
Department of Psychology
University of Geneva
* Answers to Sensory Challenges, edited by Kathleen Morris. MS CCC/SLP. 2010.(Originally published in SI Focus Magazine, Fall 2008) Article by Jeff Strong

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Tags: hearing, synchronization
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# Question
Title: Why does staring at a single point make it easier to balance on one leg?
If I'm trying to put a shoe on while standing with one leg, it's easier to maintain balance while staring at a single point (e.g., on the ground).

**Why does staring at a single point make it easier to balance on one leg?**

# Answer
# Vision and balance are linked

**Balance is fluid:**

Vision and balance are connected within the brain. Balance is not something that the brain determines, is *learned*, "this way is up" and never revisited- like this smell = coffee, this sound = a bird; it is a continual process of biofeedback.

**Three aspects of balance: vestibular system, vision and proprioception**

> Balance is the result of several body systems working together: the visual system (eyes), vestibular system (ears) and proprioception (the body's sense of where it is in space). Degeneration or loss of function in any of these systems can lead to balance deficits

We use our surrounds as a frame of reference, for our internal *spirit level.* Maintenance of an accurate *spirit level* involves continual measurement and feedback between the visual and vestibular systems, they are connected via the vestibulo-ocular reflex. When vision remains fixed upon an object, balance is achieved by the eyes moving to counteract the body's movements. These processes are interdependent, happening simultaneously, as the neurons that are stimulated within the visual system causing the neurons within the vestibular system to fire and vice versa.

Or simply put; Movement is detected by the vestibular system, and the eyes give a plane of reference, offering proprioception.

It could be likened to axes on a graph, and both dimensions (vision and vestibular) are needed to plot the point of proprioception.

**Vestibulo-ocular reflex:**

> The vestibulo-ocular reflex (VOR) is a reflex eye movement that stabilizes images on the retina during head movement by producing an eye movement in the direction opposite to head movement, thus preserving the image on the center of the visual field. For example, when the head moves to the right, the eyes move to the left, and vice versa. Since slight head movement is present all the time, the VOR is very important for stabilizing vision: patients whose VOR is impaired find it difficult to read using print, because they cannot stabilize the eyes during small head tremors. The VOR does not depend on visual input and works even in total darkness or when the eyes are closed.

Image courtesy of http://en.wikipedia.org/wiki/File:Vestibulo-ocular\_reflex\_EN.svg

**An integrated view of balance:**

> The vestibular system works with other sensorimotor systems in the body, such as the visual system and proprioceptors in muscles and joints to check and maintain the body’s position at rest or in motion. These systems enable individuals to maintain a steady focus on objects even when body position changes and to safely maneuver in the environment.
>
> The visual system specifically interacts with the vestibular system via the vestibular-ocular reflex, which senses head movements and generates equal and opposite eye movements to maintain image stability on the retinal fovea. The visual system is thought to provide continuous feedback about any retinal slip and the need to recalibrate the vestibulo-ocular reflex. (UC Davis Health System)

As we read and move our heads, our gaze is held steadily and we are able to continue reading uninterrupted thanks to the VOR. Given any alteration within the visual system, results in an alteration in our vestibular system and vice versa; when attempting a task that requires difficulty in maintaining balance, if the vision remains steady, as in constant upon an object, the vestibular system is able to measure (or locate) the body's proprioception and make adjustments to keep the vestibular system in the required plane (like the spirit level being kept level). So the effect is, we have one constant, vision and two variables; vestibular and spatial awareness.

Given the fluid nature of how the brain achieves balance; if the eyes were flitting and the visual field was varying, we have three variables. Mathematically this becomes a more complex formula for the VOR to determine where the body is spatially.

Interestingly, uncorrected poor vision can also cause poor balance when the eyes are closed.

> ... visually impaired individuals and those with uncorrected refractive error — those who could benefit from glasses to achieve normal vision but don’t wear glasses — have a significantly greater risk of diminished balance with their eyes closed on a compliant, foam surface than individuals with normal vision. (UC Davis Health System)

The link between balance and vision is an area of ongoing research.

---

References:
> 4 votes

# Answer
This answer is going to be pure speculation as I don't have any references handy, but I would argue that fixing gaze on a single spot in the world provides three separate benefits for balance. All of these benefits are related to the fact that when you are not moving very much, fixating your gaze on a single spot in the external world also tends to "lock" the head, neck, and trunk into a single pose.

1. This locking is useful because the head -- and thus the vestibular canals -- are essentially locked onto the position and orientation of the hips. When the hips move (e.g., because the leg under them wobbles), the vestibular system's movement is a direct reflection of that movement and doesn't have to be dynamically translated out of a moving, head-centered reference frame.
2. Similarly, with the head and gaze fixed on the external world, any motion in the hips or legs will translate directly to some sort of optic flow in the visual field. As with the vestibular system, this optic flow does not need to be dynamically translated into a separate reference frame as long as the head is fixed relative to the body.
3. Finally, I would argue that by locking down the trunk, neck, and head, more "bandwidth" (whatever that means) would be available in the motor system to provide control for the leg, hip, and trunk muscles. If the head and neck needed to be controlled simultaneously with the lower body, the overall control task would become more difficult.

So, my argument here essentially boils down to the idea that by locking down the head and neck, fewer dynamic translations between reference frames are needed to compute the direction and magnitude of the control signals for maintaining balance. As a practical demonstration of this effect, imagine (or try, if you have lots of cushions around you) standing on one leg while shaking your head back and forth!

This argument breaks down if you imagine turning your head upward to watch a fixed spot on the ceiling while tying your shoe ; probably it would be harder to maintain balance in such a pose, even though the head and neck are fixed. So part of the maintenance of balance also seems to be having some sort of "canonical" or "easy" pose for your body to control, so not just any head-locked pose will do. But I think the fixed-head argument is a useful way to think about the issue.
> 2 votes

---
Tags: motor, eye-movement, vestibular-system
---


# Question
Title: Sensory dissonance: Will the visual or auditory channel win?
Is there any research showing that our visual channel takes precedence over the auditory channel (or vice versa) if there is some dissonance between them?

Examples:

* Say a person driving a car approaches at fast speed a road split bang in the middle, the person next to her shouts "Right!!!" but raises his arm and clearly pointing to the left.
* Being shown the word 'Red' (coloured red) but simultaneously hearing the word 'Blue', will subjects press the red or the blue button?

# Answer
> 2 votes
Yes. The phenomenon is usually referred to as **Visual Dominance** or **Visual Capture**.

A very nice demonstration of it, is known as McGurk Effect, in which our vision of the speaker's lips biases our perception of the sound we hear \[1\]. The McGurk Effect can be seen in a demo video here. Another demonstration of a similar effect is ventriloquism, in which we perceive the sound as coming from somewhere "probable" (like a puppet's vigorously moving lips) and not from its true origin.

One early scientific research into the matter of resolution of conflicting information between senses was done by James Gibson, in a study from early 1930s \[2\], in which subjects wore prism spectacles, that made straight lines appear curved. Although this was not the main topic of the research, he reports that

> When a visually curved edge such as a meter stick was felt, it was felt as *curved*. This was true as long as the hand was watched while running up and down the edge. If the eyes were closed or turned away, the edge of course felt straight, as it in reality was. This dominance of the visual over the kinsesthetic perception was so complete that when subjects were instructed to make a strong effort to dissociate the two, i.e. to 'feel it straight and see it curved,' it was reported either difficult or impossible to do so.

Posner et al. \[3\] cite several studies showing visual dominance over proprioceptive, haptic and auditory information, both in perception and in memory judgments, and try to explain the origins of this effect.

Specifically addressing your question of vision versus audition, Colavita \[4\] conducted a study in which

> Human Ss matched an auditory and a visual stimulus for subjective magnitude. Then each stimulus was used as a cue in a reaction time task. On occasions when both stimuli were presented simultaneously, Ss’ responding was seen to be dominated by the visual stimulus. Of further interest was the finding that on some occasions of simultaneous light-tone presentation Ss were unaware that the tone had been presented. This apparent prepotency of the visual over the auditory stimulus was seen to persist across a variety of experimental conditions, which included giving Ss verbal instructions to respond to the tone when both stimuli were presented simultaneously.

However, there are also reports of the opposite case, visual information is dominated by other sources, for example by haptic information when vision is blurred \[5\].

Recently it has been claimed that it integration between senses is done an optimal way, i.e the more accurate source in each situation is given more weight in their combination, or relied upon to a larger extent \[6\]. Since vision is usually very accurate in terms of location and shape of objects in the world, it tends to be dominant more often then other senses.

---

**References**

1. McGurk, H., & MacDonald, J. (1976). Hearing lips and seeing voices.
2. Gibson, J. J. (1933). Adaptation, after-effect and contrast in the perception of curved lines. Journal of experimental psychology, 16(1), 1. PDF
3. Posner, M. I., Nissen, M. J., & Klein, R. M. (1976). Visual dominance: an information-processing account of its origins and significance. Psychological review, 83(2), 157. PDF
4. Colavita, F. B. (1974). Human sensory dominance. Perception & Psychophysics, 16(2), 409-412.
5. Heller, M. A. (1983). Haptic dominance in form perception with blurred vision. Perception, 12(5), 607-613. PDF
6. Ernst, M. O., & Banks, M. S. (2002). Humans integrate visual and haptic information in a statistically optimal fashion. Nature, 415(6870), 429-433.

---
Tags: vision, decision-making, sensation, human-factors, hearing
---


# Question
Title: Does initial 0-3 years of age have any effects for a permanent bonding to happen between the parents and their children?
My brother (age: 37) is least attached to our parents. At the time of his birth, our parents had left him with our grandmother. He saw our parents, for the first time, at the age of 3 years. He has lived with them after that till his high school.

I was wondering whether initial 0-3 years of age have any effects (positive/negative) for a permanent bonding to happen between the parents and their children? Or it isn't about age at all?

# Answer
> 2 votes
**Disclaimer:**

**~** *Firstly I would like to say that there could be many factors as to why your brother is least attached to your parents, that may have nothing to do with the separation between 0-3 years.* **~**

For the purposes of keeping this succinct, I will discuss only the effects of bonding from 0-3 years of age.

---

**Introduction:**

This is an interesting question, as much research has been done on the effects of child abuse and neglect on attachment, in this case you are discussing a (I'm assuming) healthy child from within a loving family environment.

A number of factors would also affect the attachment of such as child, in terms of why he was separated from his parents for those years.

**Overview of Development:**

Firstly there is no denying that the first three years have significant affect on how brain development, including attachment styles.

I have added yellow boxes for highlighting.

Image courtesy of:
Rethinking the brain: new insights into early development - book by Rima Shore

**Attachment 0-3 years:**

Studies would suggest that the first three years are vital for forming attachments with caregivers. A child cannot form an attachment with someone they have not met.

> A central component of attachment theory is the notion that caregivers must be present and accessible in order for their children to become attached to them. (1)

**Separation:**

It has been shown that any separation between mother and child within the first three years is detrimental to that relationship. This is assuming the mother and child already have a relationship.

> His early work demonstrated that separations as brief as one week in duration could negatively impact the quality of the relationship between mother and child (Bowlby, 1969/1982). (1)

So the same theory would apply for other caregivers in the first three years of life, in this case the grand parents.

> According to attachment theory, a secure attachment is derived from the child’s appraisal of his/her mother’s (or other attachment figure’s) availability. (1)

At this age, a child is not able to reason and can only process experience emotionally, so any parental absence is beyond comprehension of the child. The more damaging aspect of this, however, is the removal of the child at the age of three years from his/her primary caregivers (in this case the grand parents). I do not know what the situation was after your brother was returned to his parents, so it would be conjecture to discuss this in any detail.

> As previously mentioned, the reason for the separation, where the child stayed, and who provided care are all potentially informative for helping to understand the effects of separation on parents and children. A maternal separation is quite likely not as distressing to an infant if he/she is left in the care of another attachment figure to whom he/she is securely attached (1)

**In conclusion:**

It would seem that a child's complete separation from his/her parents until three years of age, would have an impact on the degree of attachment within those relationships. The people in the childs life in the first three years of life, would have closer attachments.

An observations, it is even shown in cases where children are left in abusive homes fare better with attachment styles than children who are removed and placed into foster care. Given this, the disruption to early relationships between child and caregiver is significant and has long term outcomes; in this case, the long term effect of such absence would damage the attachment to his parents.

---

References:

* (1) Early Mother-Child Separation, Parenting, and Child Well-Being in Early Head Start Families
Kimberly Howard, et al PDF
doi:10.1080/14616734.2010.488119
* Reversing the Real Brain Drain
Early Years Study PDF
* Unicef, Early Childhood Development
The key to a full and productive life PDF

---
Tags: social-psychology, developmental-psychology, parenting
---


# Question
Title: Pathological distress caused by being discouraged to say "thanks" on online communities
The Stack Exchange network users are not encouraged to leave comments expressing *thanks*.

> Please do not add a comment on your question or on an answer to say "Thank you". Comments are meant for requesting clarification, leaving constructive criticism, or adding relevant but minor additional information – not for socializing. If you want to say "thank you," vote on or accept that person's answer, or simply pay it forward by providing a great answer to someone else's question.

Given some people are taught from a preschool age to express *thanks* and this practice is reinforced throughout a lifetime. So coming to an online community can be difficult for some people not to express *thanks*.

What is happening psychologically when an individual has immense discomfort (to a point of preferring the discomfort of not complying with the wishes of an online community), that is almost compulsive in having to continue with an instilled social habit, such as expressing *thanks*.

*Nb To me, it could be related to cognitive-dissonance, but this doesn't seem to be the correct term.*

# Answer
> 1 votes
DISCLAIMER: I do not have any official education in cognitive sciences.

Maybe problem is not in saying "thank you", for me upvoting is very close to saying thank you. I think it is rather obvious what are benefits from discouraging "thank you", it would be hard to find real content in "thanks forest".

Perhaps people wish that receiver knows **who** said thank you

```
I Joe want Marc to know that 'I, Joe' am thankful.

```

---
Tags: cognitive-psychology, social-psychology, abnormal-psychology, social-networks
---


# Question
Title: What is the neurological basis for 'daredevil' behaviour?
What is the neurological basis for people being seemingly fearless and engaging in risk-taking and daredevil behaviour?

I am talking about those that frequently perform or participate in activities that are often described by a lot of people as reckless and life-threateningly dangerous.

# Answer
**Dopamine receptor agonists related to reckless driving and gambling**

There are three case reports provided by Reactions Weekly (2010) demonstrating correlations between treatment with dopamine receptor agonists and reckless driving:

> Reckless driving occurred in three patients during treatment with dopamine receptor agonists (DA) ... DA are associated with impulse control disorders, and may alter how the brain perceives and avoids risk. DA-associated impulse control disorders include pathological gambling and hypersexuality. Reckless driving may be another manifestation of DA-associated impulse control disorders.

Some further evidence is provided to suggest neurological correlates between dopamine receptor agonist and risky choices in a gambling task (Riba et al., 2008):

> In summary, the present findings indicate that the dopamine D2/D3 receptor agonist pramipexole is capable of blocking reward-related activations in the rostral basal ganglia and midbrain and may lead to a behavioral disinhibition characterized by increases in risky choices in a gambling task.

**Neurological correlates between voluntary and involuntary risk taking in the brain**

A study used functional magnetic resonance imaging (fMRI) and administered a modified BART with an active choice mode and a passive no-choice mode in order to examine the neural correlates of voluntary and involuntary risk taking in the human brain (Rao et al., 2008):

> In summary, the present study modiﬁed the BART in both active and passive modes for use during fMRI and the ﬁndings provide direct visualization of voluntary and involuntary risk processing in the human brain. Regardless of the involvement of voluntary decision making, risk in this task is processed in visual pathway regions in the occipital and parietal lobes. However, during active decision-making, risk is associated with additional robust activation in dopamine rich mesolimbic (VTA-striatum) and frontal regions (insula, ACC/MFC, and DLPFC). Voluntary decision making per se, is associated with activation in the right DLPFC, which is absent in the involuntary no-choice condition. These results contribute to understanding the neural basis of normal and high risk behavior. Extending this paradigm to pathological populations characterized by impaired decisionmaking, such as patients with drug addition and compulsive gambling, may allow the speciﬁc neural components of impaired risk behavior to be distinguished, and may ultimately inform more effective clinical treatment interventions.

**References**

* Reactions Weekly. (2010). Dopamine receptor agonists: reckless driving: 3 case reports.(Adverse Reaction Case Reports)(Case study)(Brief article), 1300, 18(1)
* Riba, J., Kramer, U.M., Heldmann, M., Richter, S. & Munte, T.F. (2008). Dopamine agonist increases risk taking but blunts reward-related brain activity. PLoS One, 3(6)
* Rao, H. Korczykowski, M., Pluta, J., Hoang, A. & Detre, J.A. (2008). Neural correlates of voluntary and involuntary risk taking in the human brain: An fMRI study of the Balloon Analog Risk Task (BART). Neuroimage, 42, 902-910
> 2 votes

# Answer
**Sensation Seeking behaviour:**

Sensation Seeking behaviour, is a better description of the type of extreme *dare devil* or *extreme sport* type of behaviour, as opposed to risk taking generally. Reckless risk taking is associated with a variety of psychological conditions that do not necessarily display this specific style of risk taking. There are gender differences with sensation seeking behaviour (and risk taking generally), with more men exhibiting this type of behaviour. From an evolutionary perspective, it makes sense that men, classically the hunters and protectors, would be more inclined to take risks.

**Type T personality:**

People who are high on the sensation seeking scale, are not necessarily anti social, but a personality type, which propels them to push the limits of life. The best description I have of this type of personality is the description of being a Type T personality. Channeled positively, this type of personality has the potential to be a high achiever.

> The Type T personality has been described as a personality dimension referring to individual differences in stimulation seeking, excitement seeking, thrill seeking, arousal seeking, and risk taking. (1)

**Physiological differences:**

Sensation seekers have notable physiological differences from individual's with average risk taking profiles. Their orienting reflex (OR) works in reverse to other individuals. In brief, OR is a creatures natural response to external stimuli, change in environment. An event that would, usually, cause a stressful response in the autonomic nervous system will trigger an entirely different response in this type of personality. Physiologically this personality type is primed for adventure.

> One study found that when subjects with high disinhibition scores were presented with a moderate-intensity tone, their heart-rates slowed down on the first exposure, while the heart rates of low sensation-seekers quickened.
> Another of his studies, published in the Journal of Personality (Vol. 58, No. 1, pages 313-345) in 1990, indicates that the differences between high and low sensation-seekers extend to the cortex of the brain, with high sensation-seekers showing an "augmenting" electrochemical reaction, or increasing amplitude of cortical-evoked potentials (EPs) in response to increasing intensities of stimulation. Low sensation-seekers, however, demonstrate a reducing reaction, showing little EP increase in relation to increasing stimulus intensity, and sometimes showing a reduction in EP amplitudes at the highest intensities of stimulation. (2)

Monoamine oxidase (MAO) is needed for the chemical cascade in the release of dopamine. The brain chemistry is also deficit in MAO, which could explain the need for a self induced high, from thrill seeking, to increase the release of dopamine.

**Conclusion:**

In conclusion these extremists, may be an evolutionary necessity for the species. As mentioned in one of the articles, it is this drive to push the boundaries that has caused the species to explore the earth and, even, outer space.

---

References:

* Gender differences in risk taking: A meta-analysis.
Byrnes, James P,et al doi: 10.1037/0033-2909.125.3.367
* Type T personality and the Jungian classification system.
Morehouse RE, et al PMID: 2313544 (1)
* Risk taking in Extreme Sports: A phenomenological perspective
Brymer, Eric PDF
* Frisky, but more risky
Christopher Munsey, American Psychological Association (2)
* Higher Nervous Functions: The Orienting Reflex
E N Sokolov DOI: 10.1146/annurev.ph.25.030163.002553
* Natural selective attention: Orienting and emotion
Margaret M. Bradley DOI: 10.1111/j.1469-8986.2008.00702.x
* Risk taking: A study in cognition and personality.
Kogan, Nathan; Wallach, Michael A, Oxford, England: Holt, Rinehart & Winston. (1964)
* Motivational determinants of risk-taking behavior. Atkinson, John W doi: 10.1037/h0043445
* The life attitudes schedule: a scale to assess adolescent life-enhancing and life-threatening behaviors.
Lewinsohn PM, et al

All supporting evidence for all my claims are within these references
> 2 votes

---
Tags: social-psychology, personality, neurology
---


# Question
Title: How can the mind be trained to accept ongoing mental or emotional suffering?
We have physical, emotional and mental needs and wants; some tangible, some intangible.

In the case where we know that some of our needs and/or wants are not going to be met; how can the mind be trained to accept the reality with an ongoing craving, learn to accept the reality and live with it, as opposed to escaping within one's imagination dreaming of the past or the future?

**For example:**

In a committed relationship where one person is not receiving romantic, emotional and sexual pleasures, how can that person learn to accept these facts without continually fantasising and desiring these pleasures with someone else?

# Answer
> How can the mind be trained to accept ongoing mental or emotional suffering?

**Experiential avoidance: avoiding what we don't like**

From the lens of Acceptance and Commitment Therapy (ACT), the process of regressing to a favourable past experience of escapism would be a maladaptive response to *experiential avoidance*. We avert our attention and stray away from the very things that cause us distress, e.g. we shift our attention to favourable past experiences with previous relationships when we are fighting with our loved ones in the present. We avoid the very things we need to deal with by distracting ourselves with other behaviours.

Experiential avoidance is defined as (EA; Hayes, Strohsahl, Wilson et al., 2004):

> ... \[an\] unwillingness to experience feelings, thoughts and sensations as well as attempts to alter them.

For example, to avoid feeling loathe and resentment for their partner, a person resorts to seemingly pleasurable activities like gambling and drinking.

**Mindfulness and psychological flexibility: seeing things the way they are**

*How do we then train the mind to address behaviours that arise from experiential avoidance?*

The model of **psychological flexibility** is a good starting point in understand how to address ongoing distress, both physical and mental. The theory of psychological flexibility is around cultivating a sustained capability to observe experiences non-judgmentally while committing to value-driven activities (Masuda et al., 2011):

> it is an overall behavior pattern of experiencing whatever one is experiencing as it is fully and non-judgmentally without excessive defense (i.e., mindfulness), while engaging in value-directed activities at the same time (i.e., commitment to actions).

Firstly, in the context of a loveless marriage, the mental training involved would be around cultivating mindfulness to observe the experiences that cause the craving for 'mental and physical pleasures'. To see things clearly is paramount. The descriptor 'loveless' is not an indicator of factual evidence that a relationship is slowly dissolving. Recognising how one uses language and how it affects cognition is important in practicing mindfulness.

Secondly, values are the key catalyst for behavioural change. By systematically seeing things as they are through non-judgmental awareness, one can train their mind in focusing on acting in-line with *'what truly matters to them'*. This has eudaemonic roots but has practical implications for psychological flexibility. Consider this very simple hypothetical example:

> X believes that he or she is in a 'loveless' marriage. This causes X a lot of psychological distress, e.g. X feels anxious and hopeless about the future with Y (partner). This anxiety manifests in thoughts such as 'I don't love Y. Why am I with Y?'. This is the language component that considerably causes a high amount of distress for X. X recognises the distress he/she feels and learns to become non-judgmentally aware and accepts that these thoughts and emotions for what they are. X identifies the values in his life that holds dear. As a result, X finds that he has greater clarity around how he should behave - he wants to be in a committed and flourishing relationship and does not want to resort to seemingly pleasurable activites, e.g. excessive alcohol, cheating etc.

**Freedom in experiencing and choosing**

So the key to accepting ongoing mental or emotional suffering is to acknowledge them non-judgmentally and recognise any avoidant behaviours that are arising. Regarding the loveless marriage, the same concept applies: be aware of the thoughts and feelings causing the avoidant behaviours, tap into your values (i.e. for a better marriage, better relationship) and act accordingly to those values. Thus, rather than consumed in mental and physical pleasures - one has the freedom to take a step back and respond to their needs rather than react to ongoing emotional turmoil. This is by no means passive resignation.

**Additional: Simple explanation on mindfulness and values**

As humans, our thoughts and feelings seem like the only source of truth in understanding ourselves and the world. However, we can get caught up in thoughts and feelings believing that they are true when they are not. This is where mindfulness and values are important.

Mindfulness refers to non-judgmental awareness of our thoughts, feelings and experiences. In some ways, we become **observers** of our thoughts and feelings and we "take a step back" rather than act on them instantly. Some of these thoughts can cause behaviours where we avoid addressing how we feel rather than sort them out. For example, assume that X has a thought - "She/He never wants to have sex. I'm so frustrated about this." Because of this, X might go and cheat on his/her partner. This is the **avoidant behaviour:** X behaves in a way that he/she does **not** address how he/she feels or is thinking. Therefore, practicising mindfulness may help us recognise how we feel and think and not act so quickly.

What next? Well, clear **values** help us know **how** we want to behave. X may realise that his/her value is to have loving, intimate and sexual relationship with someone he/she cares about. He/she may then decide to communicate with his/her partner about the problem or decide to move on. Either way, X behaves according to his/her values and not simply how he/she feels.

---

**References**

* Hayes, S.C., Strohsahl, K., Wilson, K.G., et al. (2004). Measuring experiential avoidance. A preliminary test of a working model. Psychological Record, 54, 553–578.
* Masuda, A., Anderson, P.L., Wendell, J.W., Choi, Y.Y., Price, M. & Feinstein, A.B. (2011). Psychological flexibility mediates the relations between self-concealment and negative psychological outcomes. Personality and Individual Differences, 50(2), 243-247.
> 5 votes

# Answer
I have a chronic illness and my experience is that acceptance is a function of giving up the hope that someone/something will save me and/or the hope that the world will magically re-allocate resources to compensate for the injustice of my injury. Removing these thought consuming loops forces the brain to explore new options that are more realistic.

So it might a function of learning to inhibit the seductive fantasies of rescue.
> 2 votes

---
Tags: social-psychology, emotion, clinical-psychology
---


# Question
Title: How sexual activity influences a woman's sex drive
Sheila Gregoire suggests that increasing the amount of sexual activity increases a woman's sexual desire in general. I can postulate that child bearing and raising impacts significantly upon a woman's life and that possibly, when a woman finds a mate worthwhile, it is a primitive drive to reproduce.

In studies by Winnifred B. Cutler, it is demonstrated how, as sexual frequency declines so does sex drive, for women.

HOW SEXUAL FREQUENCY AFFECTS A WOMAN'S SEXUAL RESPONSIVENESS, FERTILITY, AND HEALTH Paul H. Byerly

* **Is it true that having sex increases a women's future desire to have sex?**
* **What physiological purpose does this serve?**

# Answer
The inverse of your first question might hold generally true: that desired sexual frequency could influence a woman's actual sexual frequency.

Willoughby and Vitas (2012) conducted a study focusing on the sexual desired discrepancy between male and females. They make reference to sexual desire discrepancy (SDD) - difference between one's desired frequency of sexual intercourse and actual frequency of sexual intercourse.

> High SDD may then lead some females to put more resources into the relationship in order to work toward future sexual contact and increase the intimacy and closeness in their relationship. In this way, SDD may serve among female partners as a motivator to enhance and support the relationship as it progresses toward higher sexual frequency.

It mainly would depend on the quality and satisfaction of the sexual intercourse that would determine whether a woman's desire for greater sexual frequency would increase or not. Assuming that quality and satisfaction of sexual intercourse is high for the woman, I would say that this would increase a woman's future desire to have sex. Processes on positive expectancies give rise to higher perceived quality of the sexual relationship (McNulty & Fisher, 2008) and thus, in my opinion, if the woman expects sexual intercourse to be as good as a prior experience, they're more likely to desire it more.

So, perhaps deprivation or excess of sexual intercourse and expectancies of quality of sexual intercourse plays a major role in moulding sexual desire for women. Another thing: while the frequency of sex is predicated on the physical rewards of it for men, this may not be necessarily true for women.

---

**References**

* Willoughby, B.J. & Vitas, J. (2012). Sexual desire frequency: The effect of individual differences in desired and actual sexual frequency on dating couples. Archive of Sexual Behavior, 41, 477-486.
* McNulty, J.K. & Fisher, T.D. (2008). Gender differences in response to sexual expectancies and changes in sexual frequency: A short-term longitudinal study of sexual satisfaction in newly married couples. Archive of Sexual Behavior, 37, 229-240.
> 7 votes

---
Tags: sexuality, sex-differences
---


# Question
Title: Is there a phenomenon where one feels alienation towards certain body parts
I am wondering whether is there a name for a phenomenon where one has feelings of "alienation" or feels that body parts (limbs, internal organs, etc) do not belong to him or are not "part of his body" ?

For example - imagine a case where someone loses an arm and is transplanted with a new one, to which he feels that it does not really belong to his body.

I am looking for the name and some details about this type of psychological condition

# Answer
See the relevant psychological disorders that relate to your question:

1. Body Dysmorphic Disorder
2. Body Integrity Identity Disorder
3. Xenomelia

Xenomelia would be the most likely disorder in-line with your description. The definition is very similar to your description (Lutz and Brugger, 2012):

> Xenomelia is the oppressive feeling that one or more limbs of one’s body do not belong to one’s self.

See Sedda (2011) for a discussion around how Body integrity identity disorder may relate to Xenomelia. The author examines the possibility of BIID as being both a neurological syndrome and a psychological disorder:

> Recently, McGeoch and colleagues provided the first direct evidence that the sense on incompleteness reported by BIID patients (First 2005) finds a correspondence in a dysfunctional activity of the right parietal lobe (McGeoch et al. 2011), strongly supporting the hypothesis that BIID in not simply a paraphilia but rather a neurological syndrome (Blanke et al. 2009; Ramachandran and McGeoch 2007; Aoyama et al. in press). McGeoch and colleagues propose that ‘xenomelia’, from the Greek terms ‘foreign’ and ‘limb’, would describe this new parietal lobe syndrome better than apotemnophilia or body integrity identity disorder (McGeoch et al. 2011).

See Brugger et al. (2013) as well. They examines the mind-based and brain-based considerations in understanding the nature of the Xenomelia as a disorder in itself. I've inserted an image of a Venn diagram depicting three approaches in understanding the factors that causes Xenomelia symptoms:

A view of xenomelia research that integrates three approaches

*From:* Brugger, P., Lenggenhager, B. & Giummarra, M.J. (2013). Xenomelia: A social neuroscience view of altered bodily self-consciousness. Frontiers in Psychology, 4, 204.

---

**References**

* Hilti, L.M., Hanggi, J., Vitacco, D.A., Kraemer, B., Palla, A., Luechinger, R.J. & Brugger, P. (2012). The desire for healthy limb amputation: structural brain correlates and clinical features of xenomelia. Brain, 136(1), 318-329.
* Sedda, A. (2011). Body integrity identity disorder: From a psychological to a neurological syndrome. Neuropsychology, 21, 334-336.
* Brugger, P., Lenggenhager, B. & Giummarra, M.J. (2013). Xenomelia: A social neuroscience view of altered bodily self-consciousness. Frontiers in Psychology, 4, 204.
> 4 votes

# Answer
The condition is called **Somatoparaphrenia**, and was first described by Josef Gerstmann, in this paper:

Gerstmann, J. (1942). Problem of imperception of disease and of impaired body territories with organic lesions: relation to body scheme and its disorders. Archives of Neurology and Psychiatry, 48(6), 890.

For a more recent review of the topic, see:

Vallar, G., & Ronchi, R. (2009). Somatoparaphrenia: a body delusion. A review of the neuropsychological literature. Experimental Brain Research, 192(3), 533-551.

Relevant parts from this review's abstract:

> Somatoparaphrenia has been reported, with a few exceptions, in right-brain-damaged patients, with motor and somatosensory deficits, and the syndrome of unilateral spatial neglect. **Somatoparaphrenia, most often characterized by a delusion of disownership of left-sided body parts**, may however occur without associated anosognosia for motor deficits, and personal neglect ... Somatoparaphrenia is often brought about by extensive right-sided lesions, but patients with posterior (parietal-temporal), and insular damage are on record, as well as a few patients with subcortical lesions.
> 5 votes

---
Tags: cognitive-psychology, clinical-psychology
---


# Question
Title: Why do humans' eyes enter an unfocused gaze when recalling a memory or imagining something?
The question is self-explanatory (I hope).

Is this trait unique to humans?

Does the direction of the unfocused gaze indicate anything about which physical part of the brain is being utilized?

Is the hippocampus physically linked to the optic nerve and muscles surrounding the eye?

Is this effect related to other phenomena that are life threatening and deprive areas of the body and/or perception deemed unnecessary for survival?

# Answer
> 5 votes
**The unfocused gaze and eye direction when recalling a memory or imagining something.**

Eye movements assist in recalling spatial visual memories. The eyes move in the direction of where the object was in relation to the person, when perceived. Restricting eye movements impairs memory recall.

> In a recent study we reported that when eye movements were prohibited for participants who orally described pictures from memory, their recollections became altered and impaired (Johansson, Holsanova, Dewhurst, & Holmqvist, (in press). Journal of Experimental Psychology: Human Perception and Performance). (1)

...

> Results provide evidence that eye movements do have an active and supportive role when visuospatial information is recalled by highlighting the circumstances under which a visual memory is hampered. Additionally, findings suggest that the influence of "eye movements to nothing" is primarily related to the processing and retrieval of spatial information. (1)

**The hippocampus store long term spatial memory.**

The hippocampus is the storage centre for long term spatial memory, as it is central to the storage of much our the brains long term memory. It is not physically connected the the optic nerve, nor is it connected to the eye muscles.

Image: Optic nerves, Gray's Anatomy (copyright expired)

Image: Hippocampus within the brain, Gray's Anatomy (copyright expired)

This post How do memories come up for no apparent reason? Is this evidence that we remember everything? offers some idea about memory storage types.

*This is not a complete answer, I have not referenced comparable studies with other species.*

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**Is this effect related to other phenomena that are life threatening and deprive areas of the body and/or perception deemed unnecessary for survival**?

No, it is simply the way the body processes and recalls spatial information. The eyes move into the direction they were in when recalling spatial information to place the person in the same spatial orientation from that object.

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References:

* Eye movements play an active role when visuospatial information is recalled from memory
Johansson, et al doi: 10.1167/12.9.1256 (1)
* Spatial memory and the human hippocampus.
Shrager Y, et al
* Spatial Memory and Hippocampal Function: Where are we now?
Mark Good

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Tags: perception, memory, vision, visualization
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# Question
Title: Why do many people not use tabbed navigation (e.g. in an internet browser)?
I have noticed that many people do not use tabs even though tabs have been around in browsers for some time. I have been noticing that people either do not differentiate tabs as specific navigational elements (e.g. a web page with tabs) or do not use them even when they know what purpose they serve. A lot of people have not even heard the word "tab".

These are only my personal impressions so I am curious to learn if you have noticed otherwise. Also I know a free add-on for MS Office which gives you a tabbed window. As far as I know it is not a massive success.

**Why do some/ most people find it hard to use tabbed navigation (e.g. in an internet browser)?**

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Here is an informal study (blog published, 21 participants, all Firefox users, all students or friends of the author) that shows that most (of the recruited participants) do use tabs, but about half of the participants use them only rarely ("4 tabs for every 100 navigation actions"): http://dubroy.com/blog/how-many-tabs-do-people-use-now-with-real-data/

Since the sample in this study is not very representative (Firefox users have made a concious choice regarding browser usage and are therefore more aware of browser functionality; 21 is an extremely low number for analysing common behavior) we might safely assume that other user types (those using pre-installed browsers; those not friends to a computer nerd) will use tabs even less.

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*update:*

* a speculation just occurred to me: what if people, generally, find navigation much easier on a vertical (e.g. book contents/ web site left menu/ Win Explorer folder tree/ etc) or if not finding it easier, at least expect it there, while navigation ver a horizontal is either more difficult for some reason or unhabitual?

# Answer
Because a majority of the people are just too plain stupid.

In an international study by the OECD on adult competencies (PIAAC) that evaluated literacy, numeracy, and problem solving in technology-rich environments, it was found that only every third adult (in Germany: 36%) between 16 and 64 was able "to master more complex tasks such as navigating the internet".

Read that again. A more complex task such as navigating the internet. Only one third manages that. In an educated country like Germany where 77% of the population 14 and older use the internet.

This means that more than half the internet users don't know how to navigate the internet.

The study also found that

* every eighth person does not know how to use a computer mouse
* every fifth person only knows basic arithmetics or less
* every sixth adult (!) has the reading ability of a ten year old child

I think tabbed browsing is a minor problem. *The study makes me doubt the principles of democracy. How can people be allowed to vote, if about 15% of the adult (!) population "can at best read short texts with simple words and extract from these only very limited information"?*

Source: http://www.oecd.org/site/piaac/
> 4 votes

# Answer
### Background on strategy selection

We could categorise using tabs as a strategy for using a browser. There is a lot of research on the acquisition and use of strategies.

My thesis (see repository page with pdf link) has an extensive literature review (see page 21 onwards). To quote myself:

> Another line of research has examined how people use computer soft- ware. A common observation is that users often plateau at strategies that are asymptotically suboptimal (for a summary of this literature, see Bhavnani & John, 2000; J. M. Carroll & Rosson, 1987; Charman & Howes, 2003). Classic studies in time-and-motion found that industrial workers rarely discovered the most efficient strategies for performing their tasks (Gilbreth, 1911). Charman and Howes (2003) found that about half the participants in their study shifted to a more sophisticated graphics drawing strategy ... Charman and Howes (2003) suggested that strategy shift may be greater in the lab than in the real-world be- cause participants are focused more on low-level task goals whereas real world workers are more concerned with high-level project goals. Furthermore, any discussion of optimality raises the question of what is being optimised, and the various costs and benefits of searching for optimal strategies.
>
> Similarly, Yechiam et al. (2004) examined the use of a mouse versus a script-based strategy, along with a much slower keyboard-based strat- egy, on a spreadsheet manipulation task. Half of the participants were allowed to use the mouse strategy from the start, while the other half were required to use the script strategy initially. The script was difficult to learn, but ultimately quicker than the other strategies. They found that participants were generally unlikely to switch to the script strat- egy when it was introduced half-way through practice. Also, although Yechiam et al. (2004) did not report individual-level results, the pattern of results suggested that the shift to the using the script-based strategy tended to occur on the first or second trial of its availability or not at all. It would also seem that the shift to the script-based strategy was abrupt.

### Relating this to using tabs

Presumably you use tabs because you find that they improve your browser experience. And I can see an argument for saying that once you know how to use them, they are objectively useful.

However, that does not mean that failure to use tabs is irrational.

1. A user may not be aware of the existence of tabs or may not know how to efficiently use tabs. Presumably there are a near infinite number of things that a person is not aware of, so a user may need a general decision rule to guide them as to when to explore features of an interface. In particular, if a user is not experiencing perceived problems, they may not seek out strategies such as tabs.
2. Automaticity is a powerful thing. If a user has grown comfortable using a browser in a certain way, they can focus on what they need to get done. Being concerned about low level workflow such as using tabs can be disruptive. Thus, they may experience a temporary drop in performance as they try to learn how to use the new tool.
3. People differ in the importance of computers in their lives. The less a user uses a browser and a computer in general, the less benefit they are likely to derive from trying to optimise their interactions with the system. The complexity of representing such a system also uses cognitive resources.

Many similar arguments can be made about other computer strategies (e.g., using shortcut keys, programming versus manual approaches, using text editing keys rather than mouse based approaches, using Vim rather than notepad, etc.). None of this denies the value of tabs or other efficiency boosting strategies. I think most power users of computers develop a repertoire of skills for exploring an interface and developing an efficient workflow. However, that which is optimal or natural for a power user, may not be such for a more casual computer user.
> 3 votes

# Answer
I think that it all boils down to the fact that most people leave all settings defaulted either because they do not know they can be changed or that they do not care enough to take the time to customize their browser.
> 0 votes

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Tags: internet, hci
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# Question
Title: What exactly is IQ, and how to develop or improve it?
Some people are said to have exceptionally high IQ.
What exactly is that supposed to mean?

Is it possible to develop high IQ if one doesn't have it? If yes, then how?

# Answer
**Literal IQ**: In a literal sense, IQ is a standardised score derived from intelligence tests. Typically IQ is scaled to have a a mean of 100 and a standard deviation of 15. In that sense, it is a normative score. For children, the norm is defined relative to other children of a similar age, for adults, it is defined relative to an adult population.

**IQ as g**: But this still leaves the question of what an IQ score ultimately represents. At a slightly more abstract level, IQ scores typically measures something called  (perhaps g for general intelligence). In a statistical sense, g is the first component that is obtained when you perform a principal components or factor analysis of scores across a large number of cognitive ability tests. In non-statistical terms, when you get scores on many cognitive ability tests you find that each test will typically share something with other tests, but will also contain a unique bit. g is the common bit across many tests.

**g as intelligence**: Of course this still leaves the question of why there is the common variance across cognitive tests called g and whether we should care. IQ scores certainly correlate highly with educational performance, vocational outcomes, and many other social indicators (common correlations are in the .3 to .6 range). If you are new to intelligence, a good starting point is **Intelligence: Knowns and Unknowns** which was put together by an APA task in order to deal with some of the controversy around IQ and intelligence. It covers conceptual definitions of intelligence, correlates and more.

**Is it possible to develop IQ?** First, by IQ, I assume you mean latent IQ or latent cognitive ability. In contrast, practicing certain types of ability tests may lead to some small improvement on similar types of tests, and somewhat larger improvement on the identical test items. Cheating on a test could lead to getting a huge IQ. And all these strategies may be effective if your goal is to do well on a test perhaps for educational, vocational, or other selection purposes. However, I am assuming that you don't want to just improve on the test, you want to improve your cognitive ability in terms of the underlying ability that such tests aim to measure.

Many quick fixes to boosting intelligence are advertised under the banner such as brain training, however, there is little evidence that they are effective. And there is strong theoretical and empirical evidence that domain specific practice does not lead to general improvements in cognitive ability. See for example these earlier questions here, here.

I tend to see boosting IQ as an unproductive goal. I think a more useful aim is to try to be good at something more specific. There is plenty of evidence that humans are able to acquire domain specific expertise with practice. IQ might help in some cases, but it is often not a major limiting factor. See the expertise literature for more information about this, from which K. Anders Ericsson is probably the most famous academic.

That said, you'll see in **Intelligence: Knowns and Unknowns** interesting discussions of (a) how IQ changes over childhood, (b) the relative but not complete stability of IQ in adulthood, (c) the many interventions that have been tried to improve IQ, but that generally failed to yield long term increases, (d) the mysterious Flynn effect representing major generational increases in IQ scores, and so on. Such evidence suggests that IQ is influenced by environmental factors, but that we're not that good at understanding how to increase it. Presumably any intervention targeted at something as general as IQ would need to be similarly general, such as education or generational changes in lifestyles.
> 12 votes

# Answer
As Wikipedia tells you, the IQ, or Intelligence Quotient is:

> a score derived from one of several standardized tests designed to assess intelligence

But it is accepted, even by Mensa, the global high IQ society, that it is an indicative score, with an IQ of 100 being the normalised average for a particular country or region. So someone with a high IQ is very likely to be highly intelligent.

You can train yourself to be better at IQ tests, but the way the tests are structured mean that in order to score very highly you need to have put in the exercise from an early age:

* Learning and studying
* Problem and puzzle solving
* etc

And an element is definitely genetic. If you have high IQ parents, you have a greater likelihood of having a high IQ yourself.

As a long term member of Mensa though, I would say trying to develop a high IQ just for the purposes of having it or gaining Mensa membership are pretty pointless. Think of it instead as an indicator. Study and learn so that you know more and can do more.
> 3 votes

# Answer
IQ is intelligence quotient. It is invented by Theodoore Simon and Alfred Binet. IQ = (development age / chronological age) * 100 and it is developed to classify retarded children in elementary school.

Today IQ is something else, but it is somewhat synonym for intelligence. There is fluid crystal intelligence, spearman general factor, multi-factor theories etc, enough for several semesters in faculty of psychology. and also there is psychometry.

You can improve results on intelligence test, but you can't improve intelligence. You can make it lower by drugs, food and drinks...

There is one fun definition of intelligence worth to mention... intelligence is the entity measured by intelligence test ( circular definition, by intention).
> 2 votes

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Tags: measurement, memory, intelligence, iq, brain-training
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# Question
Title: Frequency at which electrodermal response should be measured
I'm computer science graduate working on a health monitoring device.

**How much is the delay in electrodermal response**? i.e., the time it takes before which an electrodermal response can be realized. Basically I want to calculate the rate or frequency at which the measurements should be taken without missing any relevant data.

Can someone please answer or give pointers to some article.

# Answer
These were very useful links

My understanding - The average time for which SCR response lasts is about 10 to 20 seconds. So even recording data at the frequency of 1 reading per second should be ok.
> 2 votes

# Answer
A starting point is the full text chapter "The Electrodermal Response", describes electrodermal response as being based on:

> Interest in the conductance between skin electrodes, usually placed at the palmar surface, arose because of the involvement of the sweat glands in this measurement. Since sweat gland activity, in turn, is controlled by sympathetic nerve activity, this measurement has been considered as an ideal way to monitor the autonomic nervous system

Given that it takes time for processes in the human body to occur, the time delay or latency for the electrodermal response is due to, (from the article):

> If one assumes **initial resting conditions**, then a **sweat response consists of sweat rising in the ducts** , and correspondingly R2 slowly diminishes. **The response latency is associated with the time required for this to take place.**

Further information that may be of use:

"Electrodermal response propagation time as a potential psychophysiological marker." (Silva et al. 2012). (Unfortunately the article is behind a pay-wall)

An important point from their abstract:

> So far, there is still no clear consensus regarding the relation between the specific responses of the autonomic nervous system activity, and the features typically extracted from the electrodermal activity signals.

However,

> In this paper we present an experimental setup and corresponding data analysis for electrodermal response propagation time measurement.
> 4 votes

# Answer
This is the setup I use, based on this article:

> Braithwaite, J.J., Watson, D.G., Jones, R., Rowe, M (2013). A guide for analysing electrodermal activity (EDA) and skin conductance responses (SCRs) for psychophysiological experiments via the MP36R and AcqKowledge software. Technical Report #1, Selective Attention & Awareness Laboratory (SAAL), Behavioural Brain Sciences Centre, School of Psychology, University of Birmingham, UK..

Note that the frequency you choose depends of the specific EDA component you target. The page 8 of the cited article is quite fine to answer your question.

The channel sampling rate I chose is 2kHz.
> 3 votes

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Tags: cognitive-psychology, measurement, emotion, cognitive-neuroscience
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# Question
Title: Term for urban citizens tuning out their surroundings?
I cannot for the life of me remember the term for citizens in an urban environment filtering out stimuli when in public as a regular and unconscious part of their lives.

For example commuters riding public transit and not noticing crimes or events around them because they have learned to tune out other people.

# Answer
> 4 votes
**Habituation:** habituation is the first word that comes to my mind (but see also Desensitisation).

> Habituation is a decrease in response to a stimulus after repeated presentations.

For example, the first night that you sleep in a new house, you will typically notice many noises. Over the course of a few nights you learn to progressively react less and less to the common noises as you learn that they are non-threatening and do not need to be attended to.

**Information reduction:** There's also some interesting research on information reduction as a learning mechanism. For example, Haider and Frensch have research that shows how individuals gradually ignore task information that is seemingly not relevant to performance. Thus, part of performance improvement is attending to task relevant information. Of course, when you arbitrarily manipulate a task to all of a sudden make what was irrelevant into relevant information, accuracy suffers. Relating this cognitive psychology finding to urban behaviour, people learn that 99.9% of the time noises can be ignored during the night, but one night the noise indicates that someone needs help; a person might ignore the noise because they've learnt that it generally can be ignored.

**Bystander effect:** Note that the above mechanisms are typically implicit cognitive mechanisms. There is also research on diffusion of responsibility that links in more to social psychology. This has been used to explain some people's failure to help in urban settings.

### References

* **Haider, H., & Frensch, P. A. (1996). The role of information reduction in skill acquisition. Cognitive Psychology, 30(3), 304-337.**

# Answer
> 1 votes
The closest term is "oblivious".

It was in the news a few days ago: Absorbed device users oblivious to danger

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Tags: terminology
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# Question
Title: How can I create a set of comparable symbols of different shapes?
I was thinking about doing a small experiment during university course where participants have to answer a personality quiz and then they have to compare different symbols (like triangles, rectangles of different ratios) on a split screen view, comparing two symbols at the same time, choose the preferred one and taking reaction time. Just to get information about common preferences for shapes! Obviously these symbols should have some basic information in common (pixel density, color) so shouldn't be completely different.

How can I create a set of symbols that have the same area even if they varied in geometrical form (ratio)? How should I decide which forms in which ratios should be presented?

# Answer
Presumably to have symbols with the same area but different shapes, you could do a little geometry to work out relevant angles and sides. Then in any reasonable drawing package you could draw the shapes and check that they have appropriate angles. Programming drawing packages might also make life easier, but I don't have much experience with these (e.g., tikZ).

You raise an interesting question of what represents equivalence of size. Area of the shape could be a way of making size equivalent, but alternatively you could see two shapes as being visually of a similar size if they could be contained within an equivalent sized square.

One general strategy for designing the stimuli is to consider what dimensions might contaminate pairwise judgements of preferred shape: e.g., colour, size, features of the shape (e.g., angles on a triangle, the depth of cut-ins on star like shapes, etc.). Once you've defined those features, either hold them constant or vary them in a consistent way. So you can either set up a factorial set of stimuli or randomise over features hold a feature constant. If you set up a factorial design (e.g., 3 levels of size, 2 colours, 5 shapes). You could examine how preferences vary across the confounding dimension and see whether inferences on the dimension of interest (i.e., shape) hold up levels of the confounding dimension.
> 3 votes

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Tags: perception, measurement, methodology, experimental-psychology, vision
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# Question
Title: Reducing ceiling effect with a Likert scale measure
I am designing a psychology study in which the main endpoint is the perceived effectiveness of various medical treatments. In pilot trials, we used a bipolar Likert scale to measure perceived effectiveness:

* Very ineffective
* Ineffective
* Somewhat ineffective
* Somewhat effective
* Effective
* Very effective

Unfortunately, pilot data indicate a major ceiling effect. Combining two similar pilot trials (n=73), only four responses had perceived effectiveness below "Somewhat effective":

(I'm overlaying a dotplot on a standard boxplot here.)

Are other psychometric scales better suited to separating the clustered responses at the high end of the scale? Does adding more items to the Likert scale (say, increasing to 8 options) improve matters without sacrificing too much reliability? References especially appreciated where possible.

# Answer
> 5 votes
Here are a few thoughts:

**Work out whether the construct has ceiling effects or whether it is a measurement issue:** You need to consider whether people actually discriminate between the rated objects.

**Multiple items per rated object:** For each medical treatment you could ask participants to answer several questions. You could then take the mean of their responses for the items to get an overall rating of each treatment for each participant. This increases the number of possible scores and should also increase the reliability of measurement.

**Is the aim to measure the group property or an individual property:** For example, if you are aiming to get a measure of the degree to which a group considers a treatment effective, then by averaging over many individuals you should get nuanced measure. So even if people are generally answering 4,5, and 6, one treatment will have more 4s and 5s and another might have more 5s and 6s. The result is that the mean of such ratings will still be nuanced measure, and you can then say things like one treatment having a mean of 4.5 and another having a mean of 5.5, and so on. So in that sense, you can still compare group-level opinions of effectiveness.

**Forced choice or ranking format:** You could adopt a forced choice or ranking format where participants are asked to rank or make some form of comparative assessment of the relative effectiveness of a set of treatments. This has pros and cons. It will obviously give you a good understanding of perceptions of relative effectiveness, but you will not have information on how effective they perceive the treatments relative to a general standard of effectiveness.

**Change the response scale:** There are many choices for response scales. You can add more scale points (e.g., go to 7 or 10 point scale). You could even design a scale that is not balanced, so you make more distinctions of effectiveness. Personally, I think you need a principle to govern your choice of scale. A good general rule is to talk to people doing the rating and find out what words they use to describe the effectiveness of treatments. How many distinctions do they make? What is the difference between ineffective and very ineffective in their mind?

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Tags: measurement, methodology
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# Question
Title: In SDT, how is an increase in detection sensitivity conceptualised in terms of the movement of the distributions?
Is it conceptualised as the signal distribution moving rightward, or as the noise distribution moving leftward?

# Answer
Technically it can go either way, and both situations would be conceptually and statistically equivalent. But it is conventional to fix the mean of the noise distribution at 0, so that increased discriminability corresponds graphically with the signal+noise distribution moving rightward along the latent axis.
> 6 votes

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Tags: cognitive-psychology, signal-detection
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