Heartbeat synchrony between performer and crowd - emotional resonance

Amazing observations on the annual fire walking ritual in the Spanish village of San Pedro Manrique. Researchers were stymied in their efforts to measure physiological parameters such as blood pressure, cortisol levels, or pain tolerance in individuals as they were walking across a bed of hot coals, but were able to put heart rate monitors on both fire-walkers and spectators. It was a small study, monitoring heart rates of 12 fire-walkers, 9 spectators related to fire-walkers, and 17 unrelated spectators who were just visiting.

The heart rates of relatives and friends of the fire-walkers followed an almost identical pattern to the fire-walkers’ rates, spiking and dropping almost in synchrony. The heart rates of visiting spectators did not. The relatives’ rates synchronized throughout the event, which lasted 30 minutes, with 28 fire-walkers each making five-second walks. So relatives or friends’ heart rates matched a fire-walker’s rate before, during and after his walk. Even people related to other fire-walkers showed similar patterns.

This cohesion and solidarity happened in spectators who were simply watching, not sharing with performers the movements, vocalizations, or rhythms usually presumed to accompany social bonding through emotional resonance.  (added later...here is the PNAS article on this.)

Have your legal hearing just after the judge’s lunch break.

Fascinating observations by Danziger et al.:

Are judicial rulings based solely on laws and facts? Legal formalism holds that judges apply legal reasons to the facts of a case in a rational, mechanical, and deliberative manner. In contrast, legal realists argue that the rational application of legal reasons does not sufficiently explain the decisions of judges and that psychological, political, and social factors influence judicial rulings. We test the common caricature of realism that justice is “what the judge ate for breakfast” in sequential parole decisions made by experienced judges. We record the judges’ two daily food breaks, which result in segmenting the deliberations of the day into three distinct “decision sessions.” We find that the percentage of favorable rulings drops gradually from ≈65% to nearly zero within each decision session and returns abruptly to ≈65% after a break. Our findings suggest that judicial rulings can be swayed by extraneous variables that should have no bearing on legal decisions.

Physical pain and social rejection: same brain areas

This open access article by Kross et al. is well worth a look. It is a beautiful example of piggybacking a newer kind of human social emotion on top of brain area that originally evolved to deal with physical insults:

How similar are the experiences of social rejection and physical pain? Extant research suggests that a network of brain regions that support the affective but not the sensory components of physical pain underlie both experiences. Here we demonstrate that when rejection is powerfully elicited—by having people who recently experienced an unwanted break-up view a photograph of their ex-partner as they think about being rejected—areas that support the sensory components of physical pain (secondary somatosensory cortex; dorsal posterior insula) become active. We demonstrate the overlap between social rejection and physical pain in these areas by comparing both conditions in the same individuals using functional MRI. We further demonstrate the specificity of the secondary somatosensory cortex and dorsal posterior insula activity to physical pain by comparing activated locations in our study with a database of over 500 published studies. Activation in these regions was highly diagnostic of physical pain, with positive predictive values up to 88%. These results give new meaning to the idea that rejection “hurts.” They demonstrate that rejection and physical pain are similar not only in that they are both distressing—they share a common somatosensory representation as well.

"Evolving the I" a MindBlog lecture at the Univ. of Wisconsin

I thought I would pass on to MindBlog readers a a web version of the lecture I gave last Thursday to the Evolution Seminar Series at the Univ. of Wisconsin Madison where I am an Emeritus Professor. The title and topics:

Making Minds - Evolving and Constructing the “I”

I. Evolving brains.
The Beast Within
Mirroring
Varieties of “I”

II. Developing brains
Physical environment
Social environment

III. Modeling the subjective self:
The illusion of agency
The virtual machine and virtual organs
Emotions as evolved organs of consciousness

IV. Embodied cognition
Social emotions
Metaphor
Art and Music

V. Summary - the Self Illusion

Why old folks don’t sleep as well.

Older people have an earlier phase of everyday activity compared with the young. Not only is the consolidation of sleep and wake dramatically reduced, but overall circadian amplitude of hormones and body temperature are lower. Now Pagani et al. find that the biological clocks in cells taken from young and old people have the same periods, but they can be shortened by a heat labile factor in blood serum from older people. Identification of this factor might lead to development of drugs that block its action.:

Human aging is accompanied by dramatic changes in daily sleep–wake behavior: Activity shifts to an earlier phase, and the consolidation of sleep and wake is disturbed. Although this daily circadian rhythm is brain-controlled, its mechanism is encoded by cell-autonomous circadian clocks functioning in nearly every cell of the body. In fact, human clock properties measured in peripheral cells such as fibroblasts closely mimic those measured physiologically and behaviorally in the same subjects. To understand better the molecular mechanisms by which human aging affects circadian clocks, we characterized the clock properties of fibroblasts cultivated from dermal biopsies of young and older subjects. Fibroblast period length, amplitude, and phase were identical in the two groups even though behavior was not, thereby suggesting that basic clock properties of peripheral cells do not change during aging. Interestingly, measurement of the same cells in the presence of human serum from older donors shortened period length and advanced the phase of cellular circadian rhythms compared with treatment with serum from young subjects, indicating that a circulating factor might alter human chronotype. Further experiments demonstrated that this effect is caused by a thermolabile factor present in serum of older individuals. Thus, even though the molecular machinery of peripheral circadian clocks does not change with age, some age-related circadian dysfunction observed in vivo might be of hormonal origin and therefore might be pharmacologically remediable.

Yet another distortion of democracy.

An interesting study from Davis et al., on the effects of instantaneous polling while an election debate is proceeding:

A recent innovation in televised election debates is a continuous response measure (commonly referred to as the “worm”) that allows viewers to track the response of a sample of undecided voters in real-time. A potential danger of presenting such data is that it may prevent people from making independent evaluations. We report an experiment with 150 participants in which we manipulated the worm and superimposed it on a live broadcast of a UK election debate. The majority of viewers were unaware that the worm had been manipulated, and yet we were able to influence their perception of who won the debate, their choice of preferred prime minister, and their voting intentions. We argue that there is an urgent need to reconsider the simultaneous broadcast of average response data with televised election debates.

Religion and brain atrophy...

I guess I might as well continue the religion theme of yesterday's post with this piece from Owen et al., on religious factors and hippocampal atrophy in later life:

Despite a growing interest in the ways spiritual beliefs and practices are reflected in brain activity, there have been relatively few studies using neuroimaging data to assess potential relationships between religious factors and structural neuroanatomy. This study examined prospective relationships between religious factors and hippocampal volume change using high-resolution MRI data of a sample of 268 older adults. Religious factors assessed included life-changing religious experiences, spiritual practices, and religious group membership. Hippocampal volumes were analyzed using the GRID program, which is based on a manual point-counting method and allows for semi-automated determination of region of interest volumes. Significantly greater hippocampal atrophy was observed for participants reporting a life-changing religious experience. Significantly greater hippocampal atrophy was also observed from baseline to final assessment among born-again Protestants, Catholics, and those with no religious affiliation, compared with Protestants not identifying as born-again. These associations were not explained by psychosocial or demographic factors, or baseline cerebral volume. Hippocampal volume has been linked to clinical outcomes, such as depression, dementia, and Alzheimer's Disease. The findings of this study indicate that hippocampal atrophy in late life may be uniquely influenced by certain types of religious factors.

How to decrease belief in intelligent design

Tracy et al. make the encouraging observation that teaching existential meaning in naturalism can decrease belief in intelligent design. Their research:

...examined the psychological motives underlying widespread support for intelligent design theory (IDT), a purportedly scientific theory that lacks any scientific evidence; and antagonism toward evolutionary theory (ET), a theory supported by a large body of scientific evidence. We tested whether these attitudes are influenced by IDT's provision of an explanation of life's origins that better addresses existential concerns than ET. In four studies, existential threat (induced via reminders of participants' own mortality) increased acceptance of IDT and/or rejection of ET, regardless of participants' religion, religiosity, educational background, or preexisting attitude toward evolution. Effects were reversed by teaching participants that naturalism can be a source of existential meaning (see text clip of Dawkins' writing just below), and among natural-science students for whom ET may already provide existential meaning. These reversals suggest that the effect of heightened mortality awareness on attitudes toward ET and IDT is due to a desire to find greater meaning and purpose in science when existential threats are activated.

(sample clip from Dawkins: "It is very reasonable for humans to want to understand something of our context in a broader universe, awesome and vast. It is also reasonable for us to want to understand something about ourselves. And understanding the nature of the world and the nature of ourselves is, to a very major degree, I believe, what the human enterprise is about. Truth should be pursued, and science helps us pursue it; science gives us meaning.")

Liberal and Conservative brains

Greg Miller does a commentary on Kanai et al.'s study of correlations between political orientation and brain structure. The Kanai et al. abstract:

Highlights:

-Political liberalism and conservatism were correlated with brain structure
-Liberalism was associated with the gray matter volume of anterior cingulate cortex
-Conservatism was associated with increased right amygdala size
-Results offer possible accounts for cognitive styles of liberals and conservatives

Summary:

Substantial differences exist in the cognitive styles of liberals and conservatives on psychological measures [1]. Variability in political attitudes reflects genetic influences and their interaction with environmental factors [2,3]. Recent work has shown a correlation between liberalism and conflict-related activity measured by event-related potentials originating in the anterior cingulate cortex [4]. Here we show that this functional correlate of political attitudes has a counterpart in brain structure. In a large sample of young adults, we related self-reported political attitudes to gray matter volume using structural MRI. We found that greater liberalism was associated with increased gray matter volume in the anterior cingulate cortex, whereas greater conservatism was associated with increased volume of the right amygdala. These results were replicated in an independent sample of additional participants. Our findings extend previous observations that political attitudes reflect differences in self-regulatory conflict monitoring [4] and recognition of emotional faces [5] by showing that such attitudes are reflected in human brain structure. Although our data do not determine whether these regions play a causal role in the formation of political attitudes, they converge with previous work [4,6] to suggest a possible link between brain structure and psychological mechanisms that mediate political attitudes.

Multitasking compromises short term memory in seniors.

Sigh... A careful noting "by Clapp et al. of the "deficient ability to dynamically switch between functional brain networks" that I so clearly note in my 69 year old brain as I sit here in front of my new toy, an Apple 27" cinema display monitor I'm using to do four simultaneous tasks (and can't remember activities a few steps back when I switch to a different window) ..... Their basic observation is that people between the ages of 60 and 80 have significantly more trouble remembering tasks after experiencing a brief interruption than do people in their 20s and 30s.

Multitasking negatively influences the retention of information over brief periods of time. This impact of interference on working memory is exacerbated with normal aging. We used functional MRI to investigate the neural basis by which an interruption is more disruptive to working memory performance in older individuals. Younger and older adults engaged in delayed recognition tasks both with and without interruption by a secondary task. Behavioral analysis revealed that working memory performance was more impaired by interruptions in older compared with younger adults. Functional connectivity analyses showed that when interrupted, older adults disengaged from a memory maintenance network and reallocated attentional resources toward the interrupting stimulus in a manner consistent with younger adults. However, unlike younger individuals, older adults failed to both disengage from the interruption and reestablish functional connections associated with the disrupted memory network. These results suggest that multitasking leads to more significant working memory disruption in older adults because of an interruption recovery failure, manifest as a deficient ability to dynamically switch between functional brain networks.

Neuromarketing - not ready for prime time...

I don't usually react to emails suggesting that mindblog consider mentioning what turn out to be commercial sites, but I thought the points raised by Dan Hill in this article (PDF) were quite interesting, apart from the fact this his company, Sensory Logic, would like to sell your business their services on facial analysis of emotional reactions to stimuli or services. His contention is that facial coding, which follows the response of 43 facial muscles that signal emotion, is superior to other emotional monitors such as EMG (bio feedback), EEG (electrical activity on or just below the scalp), or fMRI (brain scans).

Juvenile training improves adult skills - at a cost.

Sarro and Sanes ask whether there are long-term effects of early sensory training that can only be assessed after maturation. The experiments examine auditory processing in gerbils and find that early training in detecting amplitude modulation yield adults with abilities superior to other animals trained as adults. This would probably hold for us humans, but you don't do conditioned avoidance experiments on human infants...

Sensory experience during development can modify the CNS and alter adult perceptual skills. While this principle draws support from deprivation or chronic stimulus exposure studies, the effect of training is addressed only in adults. Here, we asked whether a brief period of training during development can exert a unique impact on adult perceptual skills. Juvenile gerbils were trained to detect amplitude modulation (AM), a stimulus feature elemental to animal communication sounds. When the performance of these juvenile-trained animals was subsequently assessed in adulthood, it was superior to a control group that received an identical regimen of training as adults. The juvenile-trained animals displayed significantly better AM detection thresholds. This was not observed in an adult group that received only exposure to AM stimuli as juveniles. To determine whether enhanced adult performance was due solely to learning the conditioned avoidance procedure, juveniles were trained on frequency modulation (FM) detection, and subsequently assessed on AM detection as adults. These animals displayed significantly poorer AM detection thresholds than all other groups. Thus, training on a specific auditory task (AM detection) during development provided a benefit to performance on that task in adulthood, whereas an identical training regimen in adulthood did not bring about this enhancement. In contrast, there was a cost, in adulthood, following developmental training on a different task (FM detection). Together, the results demonstrate a period of heightened sensitivity in the developing CNS such that behavioral training in juveniles has a unique impact on adult behavioral capabilities.

Pain reduction by mindfulness meditation - brain correlates

Zeidan et al. offer these interesting results on possible consequences of a form of mindfulness meditation called Shamatha, or focused attention, which is a cognitive practice of sustaining attention on the changing sensations of the breath, monitoring discursive events as they arise, disengaging from those events without affective reaction, and redirecting attention back to the breath. Slightly edited clips from the abstract:

The subjective experience of one's environment is constructed by interactions among sensory, cognitive, and affective processes. For centuries, meditation has been thought to influence such processes by enabling a nonevaluative representation of sensory events. To better understand how meditation influences the sensory experience, we used arterial spin labeling functional magnetic resonance imaging to assess the neural mechanisms by which mindfulness meditation influences pain in healthy human participants. After 4 d of mindfulness meditation training, meditating in the presence of noxious stimulation significantly reduced pain unpleasantness by 57% and pain intensity ratings by 40% when compared to rest... Meditation reduced pain-related activation of the contralateral primary somatosensory cortex [note: the noxious stimulus was a thermal stimulator placed on the rear right calf, and thus would be reported to the left (contralateral) somatosensory cortex]...Meditation-induced reductions in pain intensity ratings were associated with increased activity in the anterior cingulate cortex and anterior insula, areas involved in the cognitive regulation of nociceptive (pain) processing. Reductions in pain unpleasantness ratings were associated with orbitofrontal cortex activation, an area implicated in reframing the contextual evaluation of sensory events. Moreover, reductions in pain unpleasantness also were associated with thalamic deactivation, which may reflect a limbic gating mechanism involved in modifying interactions between afferent input and executive-order brain areas. Together, these data indicate that meditation engages multiple brain mechanisms that alter the construction of the subjectively available pain experience from afferent (incoming) information.

Self control makes us angry

In several different places I have come across this interesting article by Gal and Liu. Exerting self control is usually assoicated with positive emotions and wellbeing, but some research has also shown that exerting self control can lead to increased aggression. The authors:

...find that exerting self control is associated with angry behavior more broadly. In particular, using a “matched-choice paradigm,” we find that after exerting self control people exhibit increased preference for anger-themed content, greater interest in faces exhibiting anger, greater endorsement of anger-framed appeals, and greater irritation to others‟ attempts to control one‟s behavior.

The authors note that because the anger-related behaviors examined in their experiments are not inappropriate, they are unlikely to reflect diminished capacities of self-regulation. Three of the several possible reasons why exerting self-control might elicit (implicit) anger they list are:

Goal Frustration - primitive and evolutionary roots drive angry facial expressions and the autonomic response of facial flushing in a newborn baby when a sucking treat is removed.

Diminished sense of Autonomy - anger from the sense that one‟s sense of freedom is restricted and that one is "forced" to choose the virtuous path rather than indulgence.

Ego depletion - the state of being depleted (not having the short term goal deferred for the long term goal) makes people angry.

Dialing numbers on your cellphone can elicit concepts

Observations by Topolinski note an interesting consequence of our cell phone habits:

When people perform actions, effects associated with the actions are activated mentally, even if those effects are not apparent. This study tested whether sequences of simulations of virtual action effects can be integrated into a meaning of their own. Cell phones were used to test this hypothesis because pressing a key on a phone is habitually associated with both digits (dialing numbers) and letters (typing text messages).  In the first experiment, dialing digit sequences induced the meaning of words that share the same key sequence (e.g., 5683, LOVE). This occurred even though the letters were not labeled on the keypad, and participants were not aware of the digit-letter correspondences. In a second experiment, subjects preferred dialing numbers implying positive words (e.g., 37326, DREAM) over dialing numbers implying negative words (e.g., 75463, SLIME). Finally, subjects preferred companies with phone numbers implying a company-related word (e.g., LOVE for a dating agency, CORPSE for a mortician) compared with companies with phone numbers implying a company-unrelated word.

Outsourcing self regulation

It seems reasonable that thinking about supportive partners should be motivationally bolstering - leading us to work harder. Fitzsimonds and Finkel make observations that suggest just the opposite - that such thoughts are motivationally undermining, causing us to make less ambitious plans to pursue goals and to spend less time on the pursuit.
The their first experiment,

...participants who thought about how their partner helped them with health goals (as opposed to career goals) planned to spend less time and effort on health goals in the upcoming week. This pattern was stronger for depleted participants than for nondepleted participants.

In a second experiment,

...participants who thought about how their partner helped them with academic-achievement goals procrastinated more, leaving themselves less time for an academic task, than did participants in two control conditions. This pattern was stronger for participants who were told that procrastinating would drain their resources for the academic task than for participants who were told that procrastinating would not drain their resources for that task.

A final experiment

...found that participants who decreased their effort after thinking of an instrumental significant other reported higher relationship commitment to that individual than did participants who did not decrease their effort.

The authors suggest that:

...partners may develop shared self-regulatory systems, or “transactive self-control,” relying on each other for help with self-control. Individuals who rely on their romantic partner for help with self-control in one area may be able to conserve valuable resources for other goal pursuits. If so, such a shared self-regulatory system—although it could ironically undermine short-term outcomes, as in the case of the outsourcing phenomenon shown here—could ultimately benefit partners if it allowed them to best make use of their limited self-control resources over time.

A long, diligent life...

Lagergren reviews Friedman and Martin's recent book on the 8-decade long longevity study started in 1921 at Stanford University by Lewis Terman, which has followed the histories of 1,500 gifted children from schools in the state and followed them from the age of 11 into adulthood, collecting a variety of data to see what might predict later success and accomplishment. The recent update collects information on those who have died.

Some results are as expected, such as that smoking is bad for longevity. Others turn conventional wisdom on its head...working hard for long hours in a demanding job to achieve high status is better for your health and life expectancy than taking it easy and lacking ambition. Marriage is a blessing for men more than women; and men suffer more adverse health effects from divorce, perhaps turning to drink or drugs. The authors emphasize the benefits of an active social network — more common for women — as a buffer against life's harmful events. And they are critical of simple health advice, such as to jog or eat less fat, arguing that it is the whole approach to life that is essential, not the details. To give a person a list of health recommendations does not work, they point out, if the person cannot or does not follow them.

The best predictor of a long and healthy life turned out to be conscientiousness — the extent to which a child was prudent, dependable and persistent in the accomplishment of his or her goals...You do not become conscientious overnight. It is the long-term, determined work of adopting and sticking to healthy habits and seeking good social environments and relationships that makes the difference. Later follow-up of Terman's subjects showed that conscientiousness in middle age and later counts almost as much as in childhood... Conscientious people do more to protect their health and are less likely to engage in risky activities such as smoking, drinking or drug-taking, the study found. They also find their way to happier marriages, better friendships and optimum work situations. As a result, they are less likely to die from all causes...

Being physically active as a child is also a predictor of longevity, but only if that activity is maintained into and beyond middle age. The life-years gained by jogging may amount to no more than the time you spend doing it, the authors note. So we needn't all aim to run marathons; rather, we should just maintain an activity that we enjoy.

Disorder promotes discrimination and stereotyping

Stapel and Lindenberg find that environmental signs of disorder, such as uncollected trash at a train station or cars parked askew on a sidewalk, are sufficient to induce bystanders to desire orderliness. The consequences are that these bystanders elect to sit further from minorities when asked to fill in a survey and donated less of their payments (for participating in the survey) to help immigrants and the homeless. The desire for order is fulfilled by an increased propensity toward classification, which includes stereotyping. [One field study used the Utrecht train hub in the middle of the Netherlands, where thousands of travelers pass through on a daily basis. During a cleaners’ strike, the train station quickly turned into a dirty and disordered environment. After the station had not been cleaned for a few days in a row, the authors asked 40 travelers who were waiting for their train to participate in their study in return for a candy bar or an apple. They were asked to judge the extent to which they thought certain traits applied to a particular group (in their case, Muslims, homosexuals, and the Dutch). The laboratory experiments, where behaviors after pictures of order versus disorder were used, employed 40-70 subjects.]. Here is their abstract:

Being the victim of discrimination can have serious negative health- and quality-of-life–related consequences. Yet, could being discriminated against depend on such seemingly trivial matters as garbage on the streets? In this study, we show, in two field experiments, that disordered contexts (such as litter or a broken-up sidewalk and an abandoned bicycle) indeed promote stereotyping and discrimination in real-world situations and, in three lab experiments, that it is a heightened need for structure that mediates these effects (number of subjects: between 40 and 70 per experiment). These findings considerably advance our knowledge of the impact of the physical environment on stereotyping and discrimination and have clear policy implications: Diagnose environmental disorder early and intervene immediately.

Hurt the flesh, cleanse the soul....

Here are some summary, slightly edited, clips from an interesting study by Bastian et al. (performed on the usual batch of college undergraduates, paid $10 for their participation in the study):

Pain purifies. History is replete with examples of ritualized or self-inflicted pain aimed at achieving purification...When reminded of an immoral deed, people are motivated to experience physical pain. Student participants in the study who wrote about an unethical behavior not only held their hands in ice water longer but also rated the experience as more painful than did participants who wrote about an everyday interaction. Critically, experiencing pain reduced people’s feelings of guilt, and the effect of the painful task on ratings of guilt was greater than the effect of a similar but nonpainful task.

Pain has traditionally been understood as purely physical in nature, but it is more accurate to describe it as the intersection of body, mind, and culture. People give meaning to pain, and we argue that people interpret pain within a judicial model of pain as punishment. Our results suggest that the experience of pain has psychological currency in rebalancing the scales of justice—an interpretation of pain that is analogous to notions of retributive justice. Interpreted in this way, pain has the capacity to resolve guilt.

People are socialized to understand pain within this judicial framework. Physical pain is employed as a penalty (e.g., spanking children for misbehavior), and unexplained pain is often understood as punishment from God. The judicial model is explicit in the Latin word for pain, poena, which means “to pay the penalty.” Understood this way, pain may be perceived as repayment for sin in three ways. First, pain is the embodiment of atonement. Just as physical cleansing washes away sin, physical pain is experienced as a penalty, and paying that penalty reestablishes moral purity. Second, subjecting oneself to pain communicates remorse to others (including God) and signals that one has paid for one’s sins, and this removes the threat of external punishment. Third, tolerating the punishment of pain is a test of one’s virtue, reaffirming one’s positive identity to oneself and others.

Previous work has demonstrated that giving meaning to pain affects people’s management of that pain. By introducing the judicial model of pain, we emphasize that giving meaning to pain can also affect other psychological processes. Although additional research is needed, our findings demonstrate that experiencing pain as a penalty can cause people to feel that their guilt is resolved and their soul cleansed.

Improving your cognitive toolkit - VII

Continuation of my sampling of a few of the answers to the annual question at edge.org, "What scientific concept would improve everybody's cognitive toolkit?":
Alun Anderson - Homo Dilatus

Our species might well be renamed Homo Dilatus, the procrastinating ape. Somewhere in our evolution we acquired the brain circuitry to deal with sudden crises and respond with urgent action. Steady declines and slowly developing threats are quite different. "Why act now when the future is far off," is the maxim for a species designed to deal with near-term problems and not long term uncertainties. It's a handy view of humankind which everyone who uses science to change policy should keep in their mental took kit, and one that that is greatly reinforced by the endless procrastination in tacking climate change. Cancun follows Copenhagen follows Kyoto but the more we dither and no extraordinary disaster follows, the more dithering seems just fine.

Such behaviour is not unique to climate change. It took the sinking of the Titanic to put sufficient life boats on passenger ships, the huge spill from the Amoco Cadiz to set international marine pollution rules and the Exxon Valdez disaster to drive the switch to double-hulled tankers. The same pattern is seen in the oil industry, with the Gulf spill the latest chapter in the disaster first-regulations later mindset of Homo dilatus.

Geoffrey Miller - Personality traits are continuous with mental illnesses

Our instinctive way of thinking about insanity — our intuitive psychiatry — is dead wrong... There's a scientific consensus that personality traits can be well-described by five main dimensions of variation. These "Big Five" personality traits are called openness, conscientiousness, extraversion, agreeableness, and emotional stability. The Big Five are all normally distributed in a bell curve, statistically independent of each other, genetically heritable, stable across the life-course, unconsciously judged when choosing mates or friends, and found in other species such as chimpanzees. They predict a wide range of behavior in school, work, marriage, parenting, crime, economics, and politics.

Mental disorders are often associated with maladaptive extremes of the Big Five traits. Over-conscientiousness predicts obsessive-compulsive disorder, whereas low conscientiousness predicts drug addiction and other "impulse control disorders". Low emotional stability predicts depression, anxiety, bipolar, borderline, and histrionic disorders. Low extraversion predicts avoidant and schizoid personality disorders. Low agreeableness predicts psychopathy and paranoid personality disorder. High openness is on a continuum with schizotypy and schizophrenia. Twin studies show that these links between personality traits and mental illnesses exist not just at the behavioral level, but at the genetic level. And parents who are somewhat extreme on a personality trait are much more likely to have a child with the associated mental illness.