Our bias against creativity

In principle we are all for creativity, but, when faced with the prospect of actually altering our behavior or opinions we falter. Mueller et al suggest that this is a covert, largely unconscious process regulated by how uncertain we feel. Their results show that regardless of the degree to which people are open minded, when they feel motivated to reduce uncertainty (either because they have an immediate goal of reducing uncertainty or they feel uncertain generally), they may experience more negative associations with creativity, which results in lower evaluations of a creative idea. Their findings imply an irony. Other research has shown that uncertainty spurs the search for and generation of creative ideas, yet these findings reveal that uncertainty also makes people less able to recognize creativity, perhaps when they need it most. Here is the abstract.:

People often reject creative ideas, even when espousing creativity as a desired goal. To explain this paradox, we propose that people can hold a bias against creativity that is not necessarily overt and that is activated when people experience a motivation to reduce uncertainty. In two experiments, we manipulated uncertainty using different methods, including an uncertainty-reduction prime. The results of both experiments demonstrated the existence of a negative bias against creativity (relative to practicality) when participants experienced uncertainty. Furthermore, this bias against creativity interfered with participants’ ability to recognize a creative idea. These results reveal a concealed barrier that creative actors may face as they attempt to gain acceptance for their novel ideas.

IQ scores are malleable.

Brinch and Galloway do a rather clean demonstration that contests the common notion that education has little effect on IQ. Here is the abstract and one figure from the paper.:

Although some scholars maintain that education has little effect on intelligence quotient (IQ) scores, others claim that IQ scores are indeed malleable, primarily through intervention in early childhood. The causal effect of education on IQ at later ages is often difficult to uncover because analyses based on observational data are plagued by problems of reverse causation and self-selection into further education. We exploit a reform that increased compulsory schooling from 7 to 9 y in Norway in the 1960s to estimate the effect of education on IQ. We find that this schooling reform, which primarily affected education in the middle teenage years, had a substantial effect on IQ scores measured at the age of 19 y.

Average IQ and education by time to reform.

BioDigitalHuman - You've got to check out this site!

I've just spent the last two hours marveling at the incredibly elegant 3-D human anatomy website developed by BioDigital Systems (pointed to by Natashe Singer's article). (I'm finding the 3-D graphics work on either Firefox or Chrome, but not both, depending of which of my MacBook Pro laptops I'm using.  Go figure.  I use Apple computers, so can't comment on Microsoft Explorer.) You can view gross to detailed levels of skeletal, muscular, nervous, endocrine, cardiovascular, digestive, etc., systems. A click on a structure brings up a detailed description along with relevant clinical issues. I focused first on the brain (finding it helps if you first toggle off viewing the skeleton system skull that covers it. Duh!) You can zoom in and out, performing 3-D rotations to see precisely where structures are. Asking for smaller internal structure like the pituitary, or left or right amygdala, takes you to their internal location, and you can zoom in and out to appreciate how to get there. The transitions from external to internal brain structures are crude and jerky at this point, and I hope the developers will be adding more fine structure and smoother transitions during zooming. (It will take a massive amount of work to do this.)

I moved next to the muscular system, particularly around the knee joints (whose malfunctions in my case over the past year have convinced me I may no longer a teenager, in fact might be "old"). I found a more clear view of the muscles and their insertions that might underlie the pain than I've been able to get from several doctor's appointments.

Happy hunting!

Classic versus modern violins: beauty in the eye of the beholder?

It is a truism among musicians that no modern violin can, or ever will, approach the perfection of the instruments crafted by Renaissance violin makers such as Stradivari or Guarneri del Gesù in the late 17th and early 18th centuries. Nichlas Wade describes an interesting test published in PNAS that aims to determine if this is in fact the case. Violinists attending an international competition were asked to wear goggles (so they could not identify the instruments they were playing) and play three classic (a Guarneri and two Stradivari instruments) and three high quality modern violins. (It has been as pastime of physicists for years to analyze the sound qualities of old violins and devise construction techniques that could reproduce them in modern instruments.)

...participants in Dr. Fritz’s test could not reliably distinguish the old instruments from modern violins. Only 8 of the 21 subjects chose an old violin as the one they’d like to take home. In the old-to-new comparison, a Stradivarius came in last and a new violin as the most preferred.

The results are clear, even though there was grumbling from other players that the test was performed in a hotel room rather than a concert hall, so projection qualities of the instruments might not have been appreciated.

This reminds me of the numerous blind taste tests involving hundreds of people have shown no correlation between the price of wines costing from $1.50 to $150 and their reported taste. In fact, I've done a posting on the neural correlates of this effect (see also this related posting).

Are the Humanities becoming the “Animal Sciences”

A theme of my "Biology of Mind" course at the University of Wisconsin and the book of that title that I generated from my lecture notes was that our understanding of almost any aspect of our culture and literature could be enhanced by knowledge of its biological underpinnings. As more or and more of the cognitive faculties once assumed to be unique to humans are found in animals (aspects of math, language, tool use, the roots of morality) the citadel of the Humanities has increasingly taken note and an
article by James Gorman points to the consequences of this: a array of courses that bridge animal studies and human animal interactions.

This spring, freshmen at Harvard can take “Human, Animals and Cyborgs.” Last year Dartmouth offered “Animals and Women in Western Literature: Nags, Bitches and Shrews.” New York University offers “Animals, People and Those in Between.”

The existence of an emerging scholarly community is reflected by the recent formation of the Animals and Society Institute, which lists more than 100 college level courses that fit under the broad banner of animal studies. Previously ignored ethical issues in the treatment of animals are being scrutinized. The human-animal divide is being eroded as humans increasingly realize they too are animals, and subject to the same natural forces. Any cultural trend that injects just a bit more humility into us humans has to be a good thing.

Structural changes in adult brains caused by acquiring knowledge

A number of reports have appeared over the past 20 years suggesting that the hippocampus region of the brain involved in place memory is larger than normal in London Taxi drivers (who must pass a memory test of London streets to become licensed taxi drivers). Woollett and Maguire have now examined this more carefully. Their summaries:

-Trainee taxi drivers in London spend 3–4 years learning the city's layout
-We assessed the brain and memory of trainees before and after this long training
-Those who qualified experienced increased gray matter in posterior hippocampus
-Successful qualification was also associated with changes in memory profile

The last decade has seen a burgeoning of reports associating brain structure with specific skills and traits. Although these cross-sectional studies are informative, cause and effect are impossible to establish without longitudinal investigation of the same individuals before and after an intervention. Several longitudinal studies have been conducted; some involved children or young adults, potentially conflating brain development with learning, most were restricted to the motor domain, and all concerned relatively short timescales (weeks or months). Here, by contrast, we utilized a unique opportunity to study average-IQ adults operating in the real world as they learned, over four years, the complex layout of London's streets while training to become licensed taxi drivers. In those who qualified, acquisition of an internal spatial representation of London was associated with a selective increase in gray matter (GM) volume in their posterior hippocampi and concomitant changes to their memory profile. No structural brain changes were observed in trainees who failed to qualify or control participants. We conclude that specific, enduring, structural brain changes in adult humans can be induced by biologically relevant behaviors engaging higher cognitive functions such as spatial memory, with significance for the “nature versus nurture” debate.

Can ignorance promote democracy?

It is easy to despair over the continuing decay in the intelligence and rationality of American voters, and worry about their susceptibility to manipulation by loud voices offering simplistic solutions. Past work has suggested that when many individuals (human voters, flocks of birds, schools of fish) must come together to make a single collective decision, a strongly opinionated minority (tea party anyone?), might be able to exert disproportional pressure on the decision-making process. Couzin et al. develop a theoretical model in which uninformed individuals inhibit the influence of a strongly opinionated minority, returning control to the numerical majority, and in experiments on the shiner, a schooling fish, show the utility of their model. In the presence of an intransigent (and not proselytizing) minority uninformed individuals tend to adopt the opinions of those around them, amplifying the majority opinion and preventing erosion by the intransigent minority. Thus, adding uninformed individuals to a group can facilitate fair representation during the process of information integration. Here is the abstract:

Conflicting interests among group members are common when making collective decisions, yet failure to achieve consensus can be costly. Under these circumstances individuals may be susceptible to manipulation by a strongly opinionated, or extremist, minority. It has previously been argued, for humans and animals, that social groups containing individuals who are uninformed, or exhibit weak preferences, are particularly vulnerable to such manipulative agents. Here, we use theory and experiment to demonstrate that, for a wide range of conditions, a strongly opinionated minority can dictate group choice, but the presence of uninformed individuals spontaneously inhibits this process, returning control to the numerical majority. Our results emphasize the role of uninformed individuals in achieving democratic consensus amid internal group conflict and informational constraints.

Dynamics of improvising together.

In a previous life (when I was a 30-something) I frequently participated in dance improvisation sessions sponsored by either the Univ. of Wisc. Dance Department or local dance groups. One of the basic exercises was 'mirroring', two dancers generating novel movements by attempting to spontaneously generate matching movements. This worked much better when participants were equal, rather than one being designated the leader. Here is an interesting bit of work by Noy et al. describing why that was the case:

Joint improvisation is the creative action of two or more people without a script or designated leader. Examples include improvisational theater and music, and day-to-day activities such as conversations. In joint improvisation, novel action is created, emerging from the interaction between people. Although central to creative processes and social interaction, joint improvisation remains largely unexplored due to the lack of experimental paradigms. Here we introduce a paradigm based on a theater practice called the mirror game. We measured the hand motions of two people mirroring each other at high temporal and spatial resolution. We focused on expert actors and musicians skilled in joint improvisation. We found that players can jointly create novel complex motion without a designated leader, synchronized to less than 40 ms. In contrast, we found that designating one player as leader deteriorated performance: The follower showed 2–3 Hz oscillation around the leader's smooth trajectory, decreasing synchrony and reducing the range of velocities reached. A mathematical model suggests a mechanism for these observations based on mutual agreement on future motion in mirrored reactive–predictive controllers. This is a step toward understanding the human ability to create novelty by improvising together.

Have a scary memory? Erase it with prozac plus psychotherapy.

Numerous clinical studies by now have shown that a combination of antidepressant medication and psychological treatment works better for mood disorders than either therapy on its own. Karpova et al. have now ferreted out the mechanisms that might underlie this fact by investigating the effect of fluoxetine (Prozac) on fear-conditioned memories in mice. Fluoxetine accelerated extinction of fear responses, and together with extinction training disrupted fear renewal and fear reinstatement, but neither treatment by itself produced long term fear extinction. Their results suggest that fluoxetine reactivates plasticity within the amygdala, which, in combination with extinction training, can lead to the erasure of conditioned fear responses. Here is their abstract:

Antidepressant drugs and psychotherapy combined are more effective in treating mood disorders than either treatment alone, but the neurobiological basis of this interaction is unknown. To investigate how antidepressants influence the response of mood-related systems to behavioral experience, we used a fear-conditioning and extinction paradigm in mice. Combining extinction training with chronic fluoxetine, but neither treatment alone, induced an enduring loss of conditioned fear memory in adult animals. Fluoxetine treatment increased synaptic plasticity, converted the fear memory circuitry to a more immature state, and acted through local brain-derived neurotrophic factor. Fluoxetine-induced plasticity may allow fear erasure by extinction-guided remodeling of the memory circuitry. Thus, the pharmacological effects of antidepressants need to be combined with psychological rehabilitation to reorganize networks rendered more plastic by the drug treatment.

Our genes and our behavior, a paradigm shift in our understanding

I thought it would be interesting to pass on two recent items I've come across. The first is the paper by Schultz et al. (also, see commentary by Wade.) that challenges some of the leading theories of social behavior (that stress environment, larger groups sizes forcing larger more intelligent brains, stepwise progression to complexity,etc.) to argue that genetic determinants force primate species, including ours, into whatever social structures they inherit.

Compare this with the proposed article from Behavioral and Brain Sciences "Behavior genetics and post genomics", by Charney (PDF download here), which points to the much more tortuous road from genotype to phenotype. Here is his abstract:

The science of genetics is undergoing a paradigm shift. Recent discoveries, including the activity of retrotransposons, the extent of copy number variations, somatic and chromosomal mosaicism, and the nature of the epigenome as a regulator of DNA expressivity, are challenging a series of dogmas concerning the nature of the genome and the relationship between genotype and phenotype. DNA, once held to be the unchanging template of heredity, now appears subject to a good deal of environmental change; considered to be identical in all cells and tissues of the body, there is growing evidence that somatic mosaicism is the normal human condition; and treated as the sole biological agent of heritability, we now know that the epigenome, which regulates gene expressivity, can be inherited via the germline. These developments are particularly significant for behavior genetics for at least three reasons: First, these phenomena appear to be particularly prevalent in the human brain, and likely are involved in much of human behavior; second, they have important implications for the validity of heritability and gene association studies, the methodologies that largely define the discipline of behavior genetics; and third, they appear to play a critical role in development during the perinatal period, and in enabling phenotypic plasticity in offspring in particular. I examine one of the central claims to emerge from the use of heritability studies in the behavioral sciences, the principle of "minimal shared maternal effects," in light of the growing awareness that the maternal perinatal environment is a critical venue for the exercise of adaptive phenotypic plasticity. This consideration has important implications for both developmental and evolutionary biology.

Friends with benefits - pet ownership and well-being

My two abyssinian cats and I agree with the (obvious) results of this study by Harmon-Jones et al.:

Social support is critical for psychological and physical well-being, reflecting the centrality of belongingness in our lives. Human interactions often provide people with considerable social support, but can pets also fulfill one's social needs? Although there is correlational evidence that pets may help individuals facing significant life stressors, little is known about the well-being benefits of pets for everyday people. Study 1 found in a community sample that pet owners fared better on several well-being (e.g., greater self-esteem, more exercise) and individual-difference (e.g., greater conscientiousness, less fearful attachment) measures. Study 2 assessed a different community sample and found that owners enjoyed better well-being when their pets fulfilled social needs better, and the support that pets provided complemented rather than competed with human sources. Finally, Study 3 brought pet owners into the laboratory and experimentally demonstrated the ability of pets to stave off negativity caused by social rejection. In summary, pets can serve as important sources of social support, providing many positive psychological and physical benefits for their owners.

Local Jekyll and global Hyde - duality of face perception

Miellet et al. make the curious observation that we can identify faces with either focused foveal global (peripheral) vision:

The main concern in face-processing research is to understand the processes underlying the identification of faces. In the study reported here, we addressed this issue by examining whether local or global information supports face identification. We developed a new methodology called “iHybrid.” This technique combines two famous identities in a gaze-contingent paradigm, which simultaneously provides local, foveated information from one face and global, complementary information from a second face. Behavioral face-identification performance and eye-tracking data showed that the visual system identified faces on the basis of either local or global information depending on the location of the observer’s first fixation. In some cases, a given observer even identified the same face using local information on one trial and global information on another trial. A validation in natural viewing conditions confirmed our findings. These results clearly demonstrate that face identification is not rooted in a single, or even preferred, information-gathering strategy.

Figure - Procedure used to create iHybrid faces. The spatial frequencies (SFs) of two original face images (illustrated here with Brad Pitt and William H. Macy) were decomposed separately into four nonoverlapping SF bands of 1 octave each (<3, 3–6, 6–12, >12 cycles per degree of visual angle). A Gaussian window (SD = 25 pixels, ~1° of visual angle) was then centered on every potential fixation location on each face; this procedure formed a lattice of 5- × 5-pixel cells covering the original 260 × 260 image. When an observer fixated on the stimulus, the local information across the four SF bands for one identity was extracted through the Gaussian window at that location, and the complementary global SF information was extracted from the other identity. The sum of the complementary, fixation-dependent identities formed the iHybrid stimulus. In the example illustrated here, the dashed red line indicates a fixation location at the left eye; local SF information was extracted from this location in the image of Brad Pitt, and the complementary SF information was taken from the image of William H. Macy. An observer who identifies the resulting face as Brad Pitt is using local information, and an observer who identifies this face as William H. Macy is using global information.

Leaning to the left makes an object seem smaller.

From Eerland et al., here is yet another neat example of embodied cognition, how a body state can influence "objective" estimations:

In two experiments, we investigated whether body posture influences people’s estimation of quantities. According to the mental-number-line theory, people mentally represent numbers along a line with smaller numbers on the left and larger numbers on the right. We hypothesized that surreptitiously making people lean to the right or to the left would affect their quantitative estimates. Participants answered estimation questions while standing on a Wii Balance Board. Posture was manipulated within subjects so that participants answered some questions while they leaned slightly to the left, some questions while they leaned slightly to the right, and some questions while they stood upright. Crucially, participants were not aware of this manipulation. Estimates were significantly smaller when participants leaned to the left than when they leaned to the right.

Musicians use both sides of their brains more frequently.

A colleague pointed me to this interesting (to me, because I'm a pianist) work by Sohee Park's laboratory at Vanderbilt. Their central finding is that professionally trained musicians more effectively use divergent thinking (the ability to come up with new solutions to open-ended, multifaceted problems, or thinking 'outside of the box'). Creative thinking was tested both with written word association test and by asking subjects to make up new functions for a variety of household objects. Brain activity was measured by near infrared spectroscopy (NIRS), a noninvasive neuroimaging method that allows in-vivo measurement of changes in the concentrations of oxygenated hemoglobin and deoxygenated hemoglobin in the cortex. They suggest that musician's elevated use of both brain hemispheres may be related to having to use two hands independently, as well as follow multiple voices on musical scores. Folley, one of the authors, noted "“Musicians may be particularly good at efficiently accessing and integrating competing information from both hemispheres...Instrumental musicians often integrate different melodic lines with both hands into a single musical piece, and they have to be very good at simultaneously reading the musical symbols, which are like left-hemisphere-based language, and integrating the written music with their own interpretation, which has been linked to the right hemisphere.” Here is the PDF of their article, and here is the abstract:

Empirical studies of creativity have focused on the importance of divergent thinking, which supports generating novel solutions to loosely defined problems. The present study examined creativity and frontal cortical activity in an externally-validated group of creative individuals (trained musicians) and demographically matched control participants, using behavioral tasks and near-infrared spectroscopy (NIRS). Experiment 1 examined convergent and divergent thinking with respect to intelligence and personality. Experiment 2 investigated frontal oxygenated and deoxygenated hemoglobin concentration changes during divergent thinking with NIRS. Results of Experiment 1 indicated enhanced creativity in musicians who also showed increased verbal ability and schizotypal personality but their enhanced divergent thinking remained robust after co-varying out these two factors. In Experiment 2, NIRS showed greater bilateral frontal activity in musicians during divergent thinking compared with nonmusicians. Overall, these results suggest that creative individuals are characterized by enhanced divergent thinking, which is supported by increased frontal cortical activity.

Good minus God - distrust of atheists

Gervais et al offer yet another study on us poor atheists. I follow their abstract with some comments on such studies:

Recent polls indicate that atheists are among the least liked people in areas with religious majorities (i.e., in most of the world). The sociofunctional approach to prejudice, combined with a cultural evolutionary theory of religion's effects on cooperation, suggest that anti-atheist prejudice is particularly motivated by distrust. Consistent with this theoretical framework, a first study using a broad sample of American adults revealed that distrust characterized anti-atheist prejudice but not anti-gay prejudice. In subsequent studies, distrust of atheists generalized even to participants from more liberal, secular populations. In three further studies description of a criminally untrustworthy individual was seen as comparably representative of atheists and rapists but not representative of Christians, Muslims, Jewish people, feminists, or homosexuals. In addition, results were consistent with the hypothesis that the relationship between belief in God and atheist distrust was fully mediated by the belief that people behave better if they feel that God is watching them. In implicit measures, participants strongly associated atheists with distrust, and belief in God was more strongly associated with implicit distrust of atheists than with implicit dislike of atheists. Finally, atheists were systematically socially excluded only in high-trust domains; belief in God, but not authoritarianism, predicted this discriminatory decision-making against atheists in high trust domains. These 6 studies are the first to systematically explore the social psychological underpinnings of anti-atheist prejudice, and converge to indicate the centrality of distrust in this phenomenon.

In the New York Times online Opinionator, Louise Anthony makes some interesting points about such studies. A few brief clips:

I gather that many people believe that atheism implies nihilism — that rejecting God means rejecting morality. A person who denies God, they reason, must be, if not actively evil, at least indifferent to considerations of right and wrong. After all, doesn’t the dictionary list “wicked” as a synonym for “godless?” And isn’t it true, as Dostoevsky said, that “if God is dead, everything is permitted”?

Well, actually — no, it’s not. (And for the record, Dostoevsky never said it was.) Atheism does not entail that anything goes.

We “moralistic atheists” do not see right and wrong as artifacts of a divine protection racket. Rather, we find moral value to be immanent in the natural world, arising from the vulnerabilities of sentient beings and from the capacities of rational beings to recognize and to respond to those vulnerabilities and capacities in others...many theists, like many atheists, believe that moral value is inherent in morally valuable things. Things don’t become morally valuable because God prefers them; God prefers them because they are morally valuable.

Prosocial behavior as intrinsic to our brains in absence of social pressure

Zaki and Mitchell question the evolutionary and economic models assume that humans are fundamentally selfish and perform altruistic behaviors only because of social pressure:

Standard economic and evolutionary models assume that humans are fundamentally selfish. On this view, any acts of prosociality—such as cooperation, giving, and other forms of altruism—result from covert attempts to avoid social injunctions against selfishness. However, even in the absence of social pressure, individuals routinely forego personal gain to share resources with others. Such anomalous giving cannot be accounted for by standard models of social behavior. Recent observations have suggested that, instead, prosocial behavior may reflect an intrinsic value placed on social ideals such as equity and charity. Here, we show that, consistent with this alternative account, making equitable interpersonal decisions engaged neural structures involved in computing subjective value, even when doing so required foregoing material resources. By contrast, making inequitable decisions produced activity in the anterior insula, a region linked to the experience of subjective disutility. Moreover, inequity-related insula response predicted individuals’ unwillingness to make inequitable choices. Together, these data suggest that prosocial behavior is not simply a response to external pressure, but instead represents an intrinsic, and intrinsically social, class of reward.

Single nucleotide change in oxytocin receptor gene decreases stress relief by social support.

In recent years, the human oxytocin system has been increasingly studied as essential to our prosocial behavior and also buffering stress. One single nucleotide variation in the oxytocin receptor (OXTR) gene named rs53576 (G/A) involves switching between the G and A nucleotides. THe A allel of rs5376 has been associated with lower empathy, reduced reward dependence, lower optimism and self-esteem, and negative affect. Now Chen et al. find a further correlation; individuals with two copies of AA do not show lower cortisol responses to stress after social support. Here is their abstract:

The neuropeptide oxytocin has played an essential role in the regulation of social behavior and attachment throughout mammalian evolution. Because recent studies in humans have shown that oxytocin administration reduces stress responses and increases prosocial behavior, we investigated whether a common single nucleotide polymorphism (rs53576) in the oxytocin receptor gene (OXTR) might interact with stress-protective effects of social support. Salivary cortisol samples and subjective stress ratings were obtained from 194 healthy male participants before, during, and after a standardized psychosocial laboratory stress procedure. Participants were randomly assigned either to prepare alone or to receive social support from their female partner or close female friend while preparing for the stressful task. Differential stress responses between the genotype groups were observed depending on the presence or absence of social support. Only individuals with one or two copies of the G allele of rs53576 showed lower cortisol responses to stress after social support, compared with individuals with the same genotype receiving no social support. These results indicate that genetic variation of the oxytocin system modulates the effectiveness of positive social interaction as a protective buffer against a stressful experience.

A face only an investor could love...

Here is a quirky item, a bit of a stretch but curious. Given that psychological traits are thought to relate to effective leadership, Wong et al. ask whether any simple physical traits in a leader might correlate with a firms financial performance. They determined the the face width to height ratio of male leaders of 55 Fortune 500 organizations that formed part of the sample of a larger study examining the relationships among CEO characteristics, top-management-team1 processes, and organizational outcomes between 1996 and 2002:

Researchers have theorized that innate personal traits are related to leadership success. Although links between psychological characteristics and leadership success have been well established, research has yet to identify any objective physical traits of leaders that predict organizational performance. In the research reported here, we identified leaders’ facial structure as a specific physical trait that correlates with organizational performance. Specifically, we found that firms whose male CEOs have wider faces (relative to facial height) achieve superior financial performance. Decision-making dynamics within a firm’s leadership team moderate this effect, such that the relationship between a given CEO’s facial measurements and his firm’s financial performance is stronger in firms with cognitively simple leadership teams.

Figure - Industry-adjusted return on assets (ROA) as a function of the cognitive complexity of firms’ top management teams (TMTs) and CEOs’ facial width-to-height ratio (WHR). The slopes illustrated in this graph were calculated using the minimum (low) and maximum (high) values for cognitive complexity and CEO facial WHR. USD = U.S. dollars.

Our mindreading of another person depends on how much skin we see!

This interesting piece in the Journal of Personality and Social Psychology makes observations on how our mindreading, or inferring someone's nature, depends on how much of them we are seeing. From the introduction:

Do people’s mental capacities fundamentally change when they remove a sweater? This seems absurd: How could removing a piece of clothing change one’s capacity for acting or feeling? In six studies, however, we show that taking off a sweater—or otherwise revealing flesh—can significantly change the way a mind is perceived. In this article, we suggest that the kind of mind ascribed to another person depends on the relative salience of his or her body—that the perceived capacity for both pain and planned action depends on whether someone wears a sweater or tank-top.

The abstract:

According to models of objectification, viewing someone as a body induces de-mentalization, stripping away their psychological traits. Here evidence is presented for an alternative account, where a body focus does not diminish the attribution of all mental capacities but, instead, leads perceivers to infer a different kind of mind. Drawing on the distinction in mind perception between agency and experience, it is found that focusing on someone's body reduces perceptions of agency (self-control and action) but increases perceptions of experience (emotion and sensation). These effects were found in three experiments when comparing targets represented by both revealing versus nonrevealing pictures or by simply directing attention toward physical characteristics. In two further experiments he effect of a body focus on mind perception also influenced moral intuitions, with those represented as a body seen to be less morally responsible (i.e., lesser moral agents) but more sensitive to harm (i.e., greater moral patients). These effects suggest that a body focus does not cause objectification per se but, instead, leads to a redistribution of perceived mind.

Why do humans collaborate so much?

Chimpanzees apparently have the cognitive skills needed to be a good collaborator. They recognize and attend to other's goals and understand how to pick an effective cooperative partner. Yet, they collaborate very little. Tomasello and his colleagues have designed an experiment that shows that problem is one of motivation rather than understanding. They presented human children and chimpanzees with a foraging problem that could be solved equally well either individually or collaboratively. Children chose the teamwork option three quarters of the time. Chimps,in contrast, performed at chance levels, indifferent to whether a conspecific worked with them. Here is a description of the setup in Santos' review:

Participants from both species were presented with the opportunity to obtain food from one of two out-of-reach boards. To get food from the first board, participants had to pull a set of ropes on their own to move the food board closer. To access food from the second board, participants had to work collaboratively with a conspecific partner, pulling the set of ropes simultaneously with their partner to access the food. Participants from both species were then given a choice between the two boards: did they want to work with a partner or would they prefer to operate the board by themselves? The authors found a big difference across the two populations. Children preferred to obtain food using the collaborative board, choosing the teamwork option about three quarters of the time. Chimpanzees, in contrast, performed at chance; they were indifferent to whether another conspecific worked with them to solve this problem, suggesting they're not as motivated to seek out opportunities to work together.

To explore the chimps motivation in more detail:

They presented chimpanzees with a similar foraging problem to that of the previous study, but varied the payoffs across the solitary and collaborative boards. In their first study, they observed that chimpanzees show a striking preference to work by themselves when the pay-offs are equated across the two boards. They then changed the pay-off structure in the next study, allowing chimpanzees to earn more food when they worked with a partner. Only when the relative pay-off from the collaborative board was increased did chimpanzees show the kind of preference that children showed for foraging collaboratively. Chimpanzees, it seems, need a little something extra to work in a team; children are motivated to do it for free.