The Jekyll and Hyde of emotional intelligence

Côté et al. make some observations about emotional smarts:

Does emotional intelligence promote behavior that strictly benefits the greater good, or can it also advance interpersonal deviance? In the investigation reported here, we tested the possibility that a core facet of emotional intelligence—emotion-regulation knowledge—can promote both prosocial and interpersonally deviant behavior. Drawing from research on how the effective regulation of emotion promotes goal achievement, we predicted that emotion-regulation knowledge would strengthen the effects of other-oriented and self-oriented personality traits on prosocial behavior and interpersonal deviance, respectively. Among individuals with higher emotion-regulation knowledge, a first study noted that moral identity exhibited a stronger positive association with prosocial behavior in a social dilemma [i.e. the study confirmed the authors' prediction that there is an association between moral identity and prosocial behavior in a social dilemma, this association being stronger among individuals with high emotion-regulation knowledge]. A second study found that the positive relation between Machiavellianism and interpersonal deviance was stronger when emotion-regulation knowledge was high rather than when it was low, thus pointing out the dark side of emotion-regulation knowledge.

How our brain links to our immune system via vagus nerve

A large number of studies show that our psychological state can influence our immune system. Social isolation and stress weaken our immune system, and social affiliation and calm can strengthen it (the latter are associated with increased activity of the vagus nerve, which runs from the brainstem to many parts of the body). Now a multinational collaboration headed by Kevin Tracey has shown that stimulating the vagus nerve halts the pumping out of inflammatory signals by the immune system, with the neurotransmitter molecular responsible being acetyl choline - but, the Vagus nerve is not releasing it directly. Instead the splenic branch of the Vagus nerve is releasing noradrenaline in the spleen whose white blood cells (CD4 lymphocytes) are then secreting the acetyl choline which switches off production of inflammatory chemical by nearby cells. Here is the abstract:

Neural circuits regulate cytokine production to prevent potentially damaging inflammation. A prototypical vagus nerve circuit, the inflammatory reflex, inhibits tumor necrosis factor–α production in spleen by a mechanism requiring acetylcholine signaling through the  alpha 7 nicotinic acetylcholine receptor expressed on cytokine-producing macrophages. Nerve fibers in spleen lack the enzymatic machinery necessary for acetylcholine production; therefore, how does this neural circuit terminate in cholinergic signaling? We identified an acetylcholine-producing, memory phenotype T cell population in mice that is integral to the inflammatory reflex. These acetylcholine-producing T cells were required for the inhibition of cytokine production by vagus nerve stimulation. Thus, action potentials originating in the vagus nerve regulate T cells, which in turn produce the neurotransmitter acetylcholine required to control innate immune responses.

Be Happy! ... regulate your own amygdala

Not really....the conditions used in the experiments by Zotev et al.et al. - having a handy fMRI machine nearby - are not exactly accessible to most of us. Because it is known that activation of the left amygdala is associated with happy emotions, they tried a biofeedback trick:

We investigated the feasibility of training healthy humans to self-regulate the hemodynamic activity of the amygdala, which plays major roles in emotional processing. Participants in the experimental group were provided with ongoing information about the blood oxygen level dependent (BOLD) activity in the left amygdala (LA) and were instructed to raise the BOLD rtfMRI signal by contemplating positive autobiographical memories. A control group was assigned the same task but was instead provided with sham feedback from the left horizontal segment of the intraparietal sulcus (HIPS) region. In the LA, we found a significant BOLD signal increase due to rtfMRI neurofeedback training in the experimental group versus the control group...The whole brain data analysis revealed significant differences for Happy Memories versus Rest condition between the experimental and control groups...The findings demonstrate that healthy subjects can learn to regulate their amygdala activation using rtfMRI neurofeedback, suggesting possible applications of rtfMRI neurofeedback training in the treatment of patients with neuropsychiatric disorders.

Psychological resources correlate with an Oxytocin receptor gene.

Interesting work from Saphire-Bernstein et al.. An SNP is a single nucleotide polymorphism, in this case a switch at a particular site between the base adenine (A) and guanine (G) in the DNA coding for an oxytocin receptor named OXTR. Every person carries two copies of this gene (one from each parent), and the finding is that A/A or A/G individuals are less psychologically robust than G/G individuals. This suggests a strong relationship between OXTR and psychological resources. Here is the abstract:

Psychological resources—optimism, mastery, and self-esteem—buffer the deleterious effects of stress and are predictors of neurophysiological and psychological health-related outcomes. These resources have been shown to be highly heritable, yet the genetic basis for this heritability remains unknown. Here, we report a link between the oxytocin receptor (OXTR) SNP rs53576 and psychological resources, such that carriers of the “A” allele have lower levels of optimism, mastery, and self-esteem, relative to G/G homozygotes. OXTR was also associated with depressive symptomatology. Mediation analysis indicates that the effects of OXTR on depressive symptoms may be largely mediated by the influence of OXTR on psychological resources.

Income inequality, happiness, and trust.

From Oishi et al., observations that correlate with many experiments showing that people are more concerned with their relative income rank and fairness, rather than absolute income:

Using General Social Survey data from 1972 to 2008, we found that Americans were on average happier in the years with less national income inequality than in the years with more national income inequality. We further demonstrated that this inverse relation between income inequality and happiness was explained by perceived fairness and general trust. That is, Americans trusted other people less and perceived other people to be less fair in the years with more national income inequality than in the years with less national income inequality. The negative association between income inequality and happiness held for lower-income respondents, but not for higher-income respondents. Most important, we found that the negative link between income inequality and the happiness of lower-income respondents was explained not by lower household income, but by perceived unfairness and lack of trust.

Think away colds, and...Less fat, less depression

My thanks to a colleague (Ken Munkres, Emeritus Professor of Molecular Biology and Genetics at UW Madison) who sent me these two tidbits:

How to Think Away Those Cold Symptoms
Tinker Bell was right all along

Balancing Your Fat Intake Controls Depression
The intersection of diet and psychiatry

There is nothing paranormal about near-death experiences.

Mobbs and Watt argue that neuroscience can explain seeing bright lights, meeting the dead, or being convinced you are one of them, suggesting that there is nothing paranormal about these experiences. Instead, near-death experiences are the manifestation of normal brain function gone awry, during a traumatic, and sometimes harmless, event. They engage several basic features of near death experiences (awareness of being dead, out of body experiences, tunnel of light, meeting deceased people, euphoric emotions) and note the brain regions whose perturbation by electrical stimulation or ischemic strokes can induce each phenomenon. Some can be observed in normal individuals under particular conditions of sensory stimulation (I've done posts on the Blanke experiments on out of body experiences). Their arguments are of the "may be" or "could be" sort, and their summary seems to to be particularly vague hand waving...

The near-death experience is a complex set of phenomena and a single account will not capture all its components. One recent theory is that the basic arousal systems beginning in the midbrain may account for many of the components of the near-death experience. Of interest is the locus coeruleus, a midbrain region involved in the release of noradrenaline. Noradrenaline is known to be involved in arousal related to fear, stress, and hypercarbia, and is highly connected to regions that mediate emotion and memory, including the amygdala and hippocampus. Indeed, stimulation of the noradrenaline system has been shown to enhance and consolidate memory, and plays a critical role in the sleep-wake cycle, including REM sleep. Along with basic midbrain systems, such as the periaqueductal gray, a region involved in opioid analgesia and basic fear responses, and the ventral tegmental area, which is a core dopamine reward area, the noradrenaline system may be part of a basic set of systems that directly or indirectly evoke positive emotions, hallucinations and other features of the near-death experience.

Taken together, the scientific evidence suggests that all aspects of the near-death experience have a neurophysiological or psychological basis: the vivid pleasure frequently experienced in near-death experiences may be the result of fear-elicited opioid release, while the life review and REM components of the near-death experience could be attributed to the action of the locus coeruleus- noradrenaline system. Out-of-body experiences and feelings of disconnection with the physical body could arise because of a breakdown in multisensory processes, and the bright lights and tunneling could be the result of a peripheral to fovea breakdown of the visual system through oxygen deprivation. A priori expectations, where the individual makes sense of the situation by believing they will experience the archetypal near-death experience package, may also play a crucial role. If one challenge of science is to demystify the world, then research should begin to test these and other hypotheses. Only then will discussion of near-death experiences move beyond theological dialogue and into the lawful realm of empirical neurobiology.

Longevity gene debate.

A collaboration between German, French, and British laboratories is challenging the basic observations on extending life span in nematodes and fruitflies, made in American laboraties, that started off the excitement about resveratrol (in red wine) and the sirtuin genes. From Wade's review:

Both experiments were flawed, they say, because the worms and flies used as a control were not genetically identical to the test organisms. The London researchers report that they have repeated the experiments with proper controls and found that extra sirtuin does not, after all, make the worms or flies live longer.

Yoghurt lowers stress in the brain.

Here is a totally fascinating study done at the University College Cork indicating that the presence of probiotic bacteria in the gut can result in lower stress in the brain (via a pathway involving the vagus nerve and the brain neurotransmitter GABA). Perhaps that’s one reason for the longevity observed in many yogurt-eating populations. Their

...findings highlight the important role of bacteria in the bidirectional communication of the gut–brain axis and suggest that certain organisms may prove to be useful therapeutic adjuncts in stress-related disorders such as anxiety and depression.

I've started having organic yoghurt with mixes of different probiotic bacteria such as the Lactobacillus mentioned below for lunch (not the usual supermarket stuff larded with high fructose corn syrup), and of course am feeling more calm already (placebo effect, anyone?). Here is the whole abstract that notes the brain chemistry involved:

There is increasing, but largely indirect, evidence pointing to an effect of commensal gut microbiota on the central nervous system (CNS). However, it is unknown whether lactic acid bacteria such as Lactobacillus rhamnosus could have a direct effect on neurotransmitter receptors in the CNS in normal, healthy animals. GABA is the main CNS inhibitory neurotransmitter and is significantly involved in regulating many physiological and psychological processes. Alterations in central GABA receptor expression are implicated in the pathogenesis of anxiety and depression, which are highly comorbid with functional bowel disorders. In this work, we show that chronic treatment with L. rhamnosus (JB-1) induced region-dependent alterations in GABAB1b mRNA in the brain with increases in cortical regions (cingulate and prelimbic) and concomitant reductions in expression in the hippocampus, amygdala, and locus coeruleus, in comparison with control-fed mice. In addition, L. rhamnosus (JB-1) reduced GABAAα2 mRNA expression in the prefrontal cortex and amygdala, but increased GABAAα2 in the hippocampus. Importantly, L. rhamnosus (JB-1) reduced stress-induced corticosterone and anxiety- and depression-related behavior. Moreover, the neurochemical and behavioral effects were not found in vagotomized mice, identifying the vagus as a major modulatory constitutive communication pathway between the bacteria exposed to the gut and the brain. Together, these findings highlight the important role of bacteria in the bidirectional communication of the gut–brain axis and suggest that certain organisms may prove to be useful therapeutic adjuncts in stress-related disorders such as anxiety and depression.

Infidelity yields better offspring

Here is a study of birds (dark-eyed juncos) who form a social pair with one partner but produce more than one-quarter of their offspring from extra-pair matings. These young go on to reproduce more successfully than those sired within the social pair. (I could wonder if this is relevant to us humans.)

In many species, each female pairs with a single male for the purpose of rearing offspring, but may also engage in extra-pair copulations. Despite the prevalence of such promiscuity, whether and how multiple mating benefits females remains an open question. Multiple mating is typically thought to be favoured primarily through indirect benefits (i.e. heritable effects on the fitness of offspring). This prediction has been repeatedly tested in a variety of species, but the evidence has been equivocal, perhaps because such studies have focused on pre-reproductive survival rather than lifetime fitness of offspring. Here, we show that in a songbird, the dark-eyed junco (Junco hyemalis), both male and female offspring produced by extra-pair fertilizations have higher lifetime reproductive success than do offspring sired within the social pair. Furthermore, adult male offspring sired via extra-pair matings are more likely to sire extra-pair offspring (EPO) themselves, suggesting that fitness benefits to males accrue primarily through enhanced mating success. By contrast, female EPO benefited primarily through enhanced fecundity. Our results provide strong support for the hypothesis that the evolution of extra-pair mating by females is favored by indirect benefits and shows that such benefits accrue much later in the offspring's life than previously documented.

Atul Gawande on improving skilled performance by coaching

Anything Gawande writes is worth reading. I have previously noted his essays on aging and medical practice. In his most recent New Yorker essay, he discusses how expert coaching is used in many fields, and describes his own experience with recruiting a senior surgeon to improve his own experience as a surgeon.

The Buddha's Biology

I had started to occasionally re-post an old post that really struck me during my scan of this blog since its beginning in 2006, and now repeat the following old post, having come upon it for a second time:

I want to mention a book by that I have found to be a useful summary and distillation of correspondences between classical Buddhist psychology and modern psychology and evolutionary biology. Don't let its self-helpy new-agey title put you off (Buddha's Nature: A Practical Guide to Discovering Your Place in the Cosmos). It's by a crazy guy named Wes Nisker, a stand up Buddhist comic and veteran of the sixties and seventies new age San Francisco scene whose other writings include "The Big Bang, The Buddha, and the Baby Boom" and "The Essential Crazy Wisdom". It is a largely accurate descriptions of how Buddhism's four foundations of mindfulness can be taken to correspond to the bottom-up construction of our nervous system and consciousness, and to stages in the evolution of our nervous systems.

Sensing or exploring the nature of our elemental physical existence, our body breathing and homeostasis, is a focus of the Buddha's First Foundation of Mindfulness. This first foundation corresponds to physical elements of the body and homeostasis (regulation of blood flow, body temperature, etc.) These functions center in primitive brain stem structures we share with reptiles and other vertebrates. This core regulates interactions with the physical world elemental to having a self that we seldom think about - like breathing, supporting ourselves against gravity, seeing, tasting, smelling, touching, hearing.

These core structures also regulate our urge to remedy hunger, to have sex, to approach or avoid, to flee or fight when suddenly presented with very threatening situations. Our experience of these primary and instinctual basic drives, in its urgency and automaticity, has a very different quality than our experience of thoughts or more complicated emotions. The Buddha's Second Foundation of Mindfulness rests on the sentience of the nervous system which can note these elemental feelings, impressions of pleasant/unpleasant/neutral/painful, etc. We can, in more quiet moments of reflection or meditation note the more muted `flickers' of these primal forces, appearing and disappearing almost as transient quantal energies.

Our human introspective access to, observation of, emotional feelings more nuanced than the basic drives mentioned above is the focus of the Buddha's third foundation of mindfulness (affection, fear, anger, sadness, playfulness, etc.). These are regulated by a new kind of cortex that appears in mammals between the brain stem and the outer layer of the cortex, usually referred to as the limbic system.

Finally, our higher level cognitive abilities associated with the newer cortex (neocortex) that forms the top layers or our brain - our ability to note how thoughts and feelings are produced, as natural occurrences like breathing or the heartbeat - are a focus of the Buddha's fourth foundation of mindfulness.

Nisker's book has several sections of exercises or meditations useful in sensing layers of the self, its evolutionary nature, and its symbiosis with the external social and physical world.

Delayed gratification - 40 years later.

Casey et al. (open access) do a followup of the famous "marshmallow experiments" that showed young children who are better at delaying gratification to obtain a greater reward do better latter in life. They were able to test 60 individuals from the original study, now in their mid-40s, and in a subset of these were able to demonstrate stable differences in frontostriatal circuitries that integrate motivational and control processes in low delayers versus high delayers.

We examined the neural basis of self-regulation in individuals from a cohort of preschoolers who performed the delay-of-gratification task 4 decades ago. Nearly 60 individuals, now in their mid-forties, were tested on “hot” and “cool” versions of a go/nogo task to assess whether delay of gratification in childhood predicts impulse control abilities and sensitivity to alluring cues (happy faces). Individuals who were less able to delay gratification in preschool and consistently showed low self-control abilities in their twenties and thirties performed more poorly than did high delayers when having to suppress a response to a happy face but not to a neutral or fearful face. This finding suggests that sensitivity to environmental hot cues plays a significant role in individuals’ ability to suppress actions toward such stimuli. A subset of these participants (n = 26) underwent functional imaging for the first time to test for biased recruitment of frontostriatal circuitry when required to suppress responses to alluring cues. Whereas the prefrontal cortex differentiated between nogo and go trials to a greater extent in high delayers, the ventral striatum showed exaggerated recruitment in low delayers. Thus, resistance to temptation as measured originally by the delay-of-gratification task is a relatively stable individual difference that predicts reliable biases in frontostriatal circuitries that integrate motivational and control processes.

Nurture affects gender differences in spatial abilities

Here is a fascinating bit from Hoffman et al.:

Women remain significantly underrepresented in the science, engineering, and technology workforce. Some have argued that spatial ability differences, which represent the most persistent gender differences in the cognitive literature, are partly responsible for this gap. The underlying forces at work shaping the observed spatial ability differences revolve naturally around the relative roles of nature and nurture. Although these forces remain among the most hotly debated in all of the sciences, the evidence for nurture is tenuous, because it is difficult to compare gender differences among biologically similar groups with distinct nurture. In this study, we use a large-scale incentivized experiment with nearly 1,300 participants to show that the gender gap in spatial abilities, measured by time to solve a puzzle, disappears when we move from a patrilineal society to an adjoining matrilineal society. We also show that about one-third of the effect can be explained by differences in education. Given that none of our participants have experience with puzzle solving and that villagers from both societies have the same means of subsistence and shared genetic background, we argue that these results show the role of nurture in the gender gap in cognitive abilities.

Testosterone modulates brain talk in social emotional behavior.

People with higher testosterone levels show more approach-related behavior during short social exchanges, and recent work has shown that this hormone influences activity of the amygdala (central to emotional behavior) and the ventral lateral (VLPFC) and orbital frontal (OFC) prefrontal areas of our cortex. I'm passing on this link to an open access article by Volman et al. that details experiments showing that testosterone modulates the effective connectivity between amygdala and VLPFC in approach-avoidance behavior. Their results indicate that endogenous testosterone influences local prefrontal activity and interregional connectivity supporting the control of social emotional behavior.

Evolutionary rationale for positive illusions.

Johnson and Fowler offer a fascinating explanation for why 70% of us (and 90% of college professors) feel we are above average in physical skills, intelligence, leadership, importance to our groups, driving skills, healthiness of our behavior, etc. etc. The authors make the striking suggestion that biased self-beliefs can actually lead people to make the right decision, whereas unbiased self-images would lead to a suboptimal decision. In their model overconfident populations are evolutionarily stable over a more wide range of environments than realistic populations, and they suggest this "may help to explain why overconfidence remains prevalent today, even if it contributes to hubris, market bubbles, financial collapses, policy failures, disasters and costly wars." Here is their abstract:

Confidence is an essential ingredient of success in a wide range of domains ranging from job performance and mental health to sports, business and combat. Some authors have suggested that not just confidence but overconfidence—believing you are better than you are in reality—is advantageous because it serves to increase ambition, morale, resolve, persistence or the credibility of bluffing, generating a self-fulfilling prophecy in which exaggerated confidence actually increases the probability of success. However, overconfidence also leads to faulty assessments, unrealistic expectations and hazardous decisions, so it remains a puzzle how such a false belief could evolve or remain stable in a population of competing strategies that include accurate, unbiased beliefs. Here we present an evolutionary model showing that, counterintuitively, overconfidence maximizes individual fitness and populations tend to become overconfident, as long as benefits from contested resources are sufficiently large compared with the cost of competition. In contrast, unbiased strategies are only stable under limited conditions. The fact that overconfident populations are evolutionarily stable in a wide range of environments may help to explain why overconfidence remains prevalent today, even if it contributes to hubris, market bubbles, financial collapses, policy failures, disasters and costly wars.

Rewriting self-fulfilling prophecies about social rejection

Stinson et al. provide yet another example of how even a very modest intervention to alter self-image can have long lasting effects:

Chronically insecure individuals often behave in ways that result in the very social rejection that they most fear. We predicted that this typical self-fulfilling prophecy is not immutable. Self-affirmation may improve insecure individuals’ relational security, and this improvement may allow them to express more welcoming social behavior. In a longitudinal experiment, a 15-min self-affirmation improved both the relational security and experimenter-rated social behavior of insecure participants up to 4 weeks after the initial intervention. Moreover, the extent to which self-affirmation improved insecure participants’ relational security at 4 weeks predicted additional improvements in social behavior another 4 weeks after that. Our finding that insecure participants continued to reap the social benefits of self-affirmation up to 8 weeks after the initial intervention demonstrates that it is indeed possible to rewrite the self-fulfilling prophecy of social rejection.

The experiment used the usual gaggle of psychology undergraduates. After answering a relational security questionaire,

Participants were assigned to one of two conditions, in both of which they ranked 11 values (e.g., academics) according to personal importance. Participants in the self-affirmation condition were instructed to write several paragraphs describing why their top-ranked value was important to them. They then listed the top two reasons why they picked that value as most important and indicated the extent to which their top-ranked value influenced their lives and was an important part of their self-image. Participants in the control condition were also instructed to write several paragraphs and answer similar questions, except that we asked this group to focus on their ninth-ranked value and why it might be important to someone else.

Musical expertise boosts language perception

Perhaps the thousands of hours I have put in on piano practice have made it easier for me to write? A few clips from the introduction of Francois and Schön :

The fact that musicians perceive some sound features more accurately than nonmusicians do is not so surprising. After all, they spend hours and hours of their life focusing on sounds and the way they are generated, paying particular attention to pitch, timber, duration, and timing. However, what seems less evident to us is whether or not this intensive musical practice can affect nonmusical abilities. Several recent studies seem to confirm this possibility….In this study, we took the challenge of focusing on a rather high cognitive function: word segmentation, namely, the ability to extract words from continuous speech…Participants listened to an artificial sung language (wherein music and language dimensions are highly intertwined) and were then tested with a 2-alternative forced-choice task on pairs of words and melodies (familiar vs. unfamiliar). The main goal of this study was to test whether musical expertise can facilitate word segmentation. With this aim, we compared 2 groups, one group with formal musical training and one without.

And here is their abstract:

Musical training is known to modify auditory perception and related cortical organization. Here, we show that these modifications may extend to higher cognitive functions and generalize to processing of speech. Previous studies have shown that adults and newborns can segment a continuous stream of linguistic and nonlinguistic stimuli based only on probabilities of occurrence between adjacent syllables or tones. In the present experiment, we used an artificial (sung) language learning design coupled with an electrophysiological approach. While behavioral results were not clear cut in showing an effect of expertise, Event-Related Potentials data showed that musicians learned better than did nonmusicians both musical and linguistic structures of the sung language. We discuss these findings in terms of practice-related changes in auditory processing, stream segmentation, and memory processes.

Neural correlates of pain reduction through meditation

Salomons and Kucyi present a nice review of experiments examining meditation and pain reduction (PDF here).

...A cognitive mechanism that is thought to be unique to mindfulness is the combination of increased attention and reduced negative evaluation...the key to reported analgesic effects of meditation training might be the co-occurring reduction in emotional and evaluative responses. Thus it is noteworthy that [several experiments] found activation patterns in regions associated with downregulation of negative affective responses, and functional decoupling of dorso-lateral prefrontal cortex and cingulate...attributed to dissociation between attention to pain and evaluation of pain. Zeidan and colleagues noted an inverse correlation between OFC activation and unpleasantness ratings, which was attributed to altered processing of reward and hedonic experiences. The degree of concordance between these studies suggests that meditative practices may indeed reduce pain through a unique neural mechanism, one corresponding to increased attention and reduced evaluative/emotional responses.

Why laughing feels so good...

Robin Dunbar, the evolutionary psychologist at Oxford who has correlated social group size with brain size in evolution, and also argued for the importance of grooming as a group bonding mechanism, has come up with a simple and fascinating observation: social laughter increases pain resistance, suggesting that moving the muscles that are involved in a laugh causes the release of endorphins (Pain thresholds are taken to be a proxy for endorphin release). Here is the abstract from Dunbar et al.:

Although laughter forms an important part of human non-verbal communication, it has received rather less attention than it deserves in both the experimental and the observational literatures. Relaxed social (Duchenne) laughter is associated with feelings of wellbeing and heightened affect, a proximate explanation for which might be the release of endorphins. We tested this hypothesis in a series of six experimental studies in both the laboratory (watching videos) and naturalistic contexts (watching stage performances), using change in pain threshold as an assay for endorphin release. The results show that pain thresholds are significantly higher after laughter than in the control condition. This pain-tolerance effect is due to laughter itself and not simply due to a change in positive affect. We suggest that laughter, through an endorphin-mediated opiate effect, may play a crucial role in social bonding.

In a review James Gorman quotes Dunbar:

“Laughter is very weird stuff, actually,” Dr. Dunbar said. “That’s why we got interested in it.” And the findings fit well with a growing sense that laughter contributes to group bonding and may have been important in the evolution of highly social humans....Social laughter, Dr. Dunbar suggests, relaxed and contagious, is “grooming at a distance,” an activity that fosters closeness in a group the way one-on-one grooming, patting and delousing promote and maintain bonds between individual primates of all sorts.