Monetary favors bias judgement in unrelated domains

Work from Read Montague's group at Baylor College of Medicine in Houston, Texas, that explains how corporate sponsorship (of athletic or artistic events) can bias our judgements in a very general way:

Favors from a sender to a receiver are known to bias decisions made by the recipient, especially when the decision relates to the sender, a feature of social exchange known as reciprocity. Using an art-viewing paradigm possessing no objectively correct answer for preferring one piece of art over another, we show that sponsorship of the experiment by a company endows the logo of the company with the capacity to bias revealed preference for art displayed next to the logo. Merely offering to sponsor the experiment similarly endowed the gesturing logo of the company with the capacity to bias revealed preferences. These effects do not depend upon the size of the displayed art or the proximity of the sponsoring logo to the piece of art. We used functional magnetic resonance imaging to show that such monetary favors do not modulate a special collection of brain responses but instead modulate responses in neural networks normally activated by a wide range of preference judgments. The results raise the important possibility that monetary favors bias judgments in domains seemingly unrelated to the favor but nevertheless act in an implicit way through neural networks that underlie normal, ongoing preference judgments.

Our bias towards negative interpretation of ambiguous faces

Neta and Whalen make some interesting observations (on the usual cadre of undergraduate psychology students usually involved in such studies), showing that we have a 'better be safe than sorry' strategy in responding to ambiguous expressions of surprise that could signal either a negative or positive situation.  We pick the negative interpretation, and our background bias towards being positive or negative biases this effect.:

Low-spatial-frequency (LSF) visual information is processed in an elemental fashion before a finer analysis of high-spatial-frequency information. Further, the amygdala is particularly responsive to LSF information contained within negative (e.g., fearful) facial expressions. In a separate line of research, it has been shown that surprised facial expressions are ambiguous in that they can be interpreted as either negatively or positively valenced. More negative interpretations of surprise are associated with increased ventral amygdala activity. In this report, we show that LSF presentations of surprised expressions bias the interpretation of surprised expressions in a negative direction, a finding suggesting that negative interpretations are first and fast during the resolution of ambiguous valence.

Nuturing robots

A recent article by Benedict Carey suggests we may be heading towards a future in which instructional and emotional needs of those not able to obtain appropriate human contact are met through presentation of changing robotic emotional expressions that activate the same brain areas as normal human gestures. A report by Chaminade et al., however, on a multi-national collaboration involving the humanoid robot WE4-RII - which expresses emotions by using facial expressions and the movement of the upper-half of the body including neck, shoulders, trunk, waist, as well as arms and hands - suggests that we have some way to go:

...activity in cortical areas endowed with mirror properties, like left Broca's area for the perception of speech, and in the processing of emotions like the left anterior insula for the perception of disgust and the orbitofrontal cortex for the perception of anger, is reduced for robot stimuli, suggesting lesser resonance with the mechanical agent. Finally, instructions to explicitly attend to the emotion significantly increased response to robot, but not human facial expressions in the anterior part of the left inferior frontal gyrus, a neural marker of motor resonance.

The Carey article reviews a number of different robotic instructional studies that show, in spite of the attenuated effectiveness of robotic versus human emotions, that robots can engage people and teach them simple skills, including household tasks, vocabulary or, in the case of autistic children, playing, elementary imitation and taking turns.

Perceptual training enhances working memory in older adults.

Berry et al. demonstrate that training the visual discrimination of older adults enhances working memory, a cross-domain brain enhancement. (The visual discrimination task involved detecting whether a sine pattern grating was expanding or contracting. Training was adaptive such that the speed of expansion/contraction and the duration of the inter-stimulus interval scaled with improvements in response accuracy, so as to continuously challenge the trainees. The working memory test used a delayed recognition paradigm.):

Normal aging is associated with a degradation of perceptual abilities and a decline in higher-level cognitive functions, notably working memory. To remediate age-related deficits, cognitive training programs are increasingly being developed. However, it is not yet definitively established if, and by what mechanisms, training ameliorates effects of cognitive aging. Furthermore, a major factor impeding the success of training programs is a frequent failure of training to transfer benefits to untrained abilities. Here, we offer the first evidence of direct transfer-of-benefits from perceptual discrimination training to working memory performance in older adults. Moreover, using electroencephalography to evaluate participants before and after training, we reveal neural evidence of functional plasticity in older adult brains, such that training-induced modifications in early visual processing during stimulus encoding predict working memory accuracy improvements. These findings demonstrate the strength of the perceptual discrimination training approach by offering clear psychophysical evidence of transfer-of-benefit and a neural mechanism underlying cognitive improvement.

Sex promotes generation of new brain cells.

Stress usually adversely affects hippocampal structure and function in adult rats, inhibits cell division, and produces anxiety-like behavior. Leuner et al. show, however, that the stress associated with repeated (chronic) copulation has the opposite effect. The generation of new cells by cell division is stimulated and anxiety-like behaviors diminish. (Is this why I feel so mellow after...?) Here is the abstract:

Aversive stressful experiences are typically associated with increased anxiety and a predisposition to develop mood disorders. Negative stress also suppresses adult neurogenesis and restricts dendritic architecture in the hippocampus, a brain region associated with anxiety regulation. The effects of aversive stress on hippocampal structure and function have been linked to stress-induced elevations in glucocorticoids. Normalizing corticosterone levels prevents some of the deleterious consequences of stress, including increased anxiety and suppressed structural plasticity in the hippocampus. Here we examined whether a rewarding stressor, namely sexual experience, also adversely affects hippocampal structure and function in adult rats. Adult male rats were exposed to a sexually-receptive female once (acute) or once daily for 14 consecutive days (chronic) and levels of circulating glucocorticoids were measured. Separate cohorts of sexually experienced rats were injected with the thymidine analog bromodeoxyuridine in order to measure cell proliferation and neurogenesis in the hippocampus. In addition, brains were processed using Golgi impregnation to assess the effects of sexual experience on dendritic spines and dendritic complexity in the hippocampus. Finally, to evaluate whether sexual experience alters hippocampal function, rats were tested on two tests of anxiety-like behavior: novelty suppressed feeding and the elevated plus maze. We found that acute sexual experience increased circulating corticosterone levels and the number of new neurons in the hippocampus. Chronic sexual experience no longer produced an increase in corticosterone levels but continued to promote adult neurogenesis and stimulate the growth of dendritic spines and dendritic architecture. Chronic sexual experience also reduced anxiety-like behavior. These findings suggest that a rewarding experience not only buffers against the deleterious actions of early elevated glucocorticoids but actually promotes neuronal growth and reduces anxiety.

MRI evidence on how hypnosis works.

I just came across a paper by Cojan et al. on brain activity under hypnosis. While undergoing functional MRI, participants were instructed to prepare to move their hand. After a few seconds they were told whether or not to actually perform the movement. Some of the time, they were hypnotized and believed that their hand was paralyzed. Interestingly, when the volunteers were under hypnosis, the preparatory activity in motor cortex was normal; but there was increased activity in other regions related to attention, mental imagery and self-awareness. Moreover, the connectivity between these regions and motor cortex was enhanced, indicating that hypnosis doesn’t work by directly controlling motor activity, but rather through the effects of internal representations and self-monitoring processes on such activity. Here is the authors' summary of the work:

Brain mechanisms of hypnosis are poorly known. Cognitive accounts proposed that executive attentional systems may cause selective inhibition or disconnection of some mental operations. To assess motor and inhibitory brain circuits during hypnotic paralysis, we designed a go-nogo task while volunteers underwent functional magnetic resonance imaging (fMRI) in three conditions: normal state, hypnotic left-hand paralysis, and feigned paralysis. Preparatory activation arose in right motor cortex despite left hypnotic paralysis, indicating preserved motor intentions, but with concomitant increases in precuneus regions that normally mediate imagery and self-awareness. Precuneus also showed enhanced functional connectivity with right motor cortex. Right frontal areas subserving inhibition were activated by nogo trials in normal state and by feigned paralysis, but irrespective of motor blockade or execution during hypnosis. These results suggest that hypnosis may enhance self-monitoring processes to allow internal representations generated by the suggestion to guide behavior but does not act through direct motor inhibition.

Directly controlling 'fear' cells in the brain.

LeDoux and collaborators have done the clever experiment (in rats) of introducing an optically activated molecular label into cells in the amygdala thought to be causal in fear conditioning. Activation of these cells by light just after presentation of a auditory sensory cue (but with no aversive stimulus) caused the rats to exhibit behavioral fear responses when the cue was subsequently presented.

Humans and animals can learn that specific sensory cues in the environment predict aversive events through a form of associative learning termed fear conditioning. This learning occurs when the sensory cues are paired with an aversive event occuring in close temporal proximity. Activation of lateral amygdala (LA) pyramidal neurons by aversive stimuli is thought to drive the formation of these associative fear memories; yet, there have been no direct tests of this hypothesis. Here we demonstrate that viral-targeted, tissue-specific expression of the light-activated channelrhodopsin (ChR2) in LA pyramidal cells permitted optical control of LA neuronal activity. Using this approach we then paired an auditory sensory cue with optical stimulation of LA pyramidal neurons instead of an aversive stimulus. Subsequently presentation of the tone alone produced behavioral fear responses. These results demonstrate in vivo optogenetic control of LA neurons and provide compelling support for the idea that fear learning is instructed by aversive stimulus-induced activation of LA pyramidal cells.

Fool the brain to enhance performance with a carbohydrate rinse

Kolata reports on exercise physiologists stumbling on an unexpected feature: simply rinsing the mouth with a carbohydrate solution stimulates receptors that report to the brain, causing it to instruct increased intensity and duration of effort in anticipation of an imminent food reward.

Our dread of idleness

Being a hyper-purposeful person myself, I've always been attracted to the opposite pole represented by The Idler,  both the original book and the subsequent magazine whose intention is "to return dignity to the art of loafing, to make idling into something to aspire towards rather than reject."  Thus I thought this piece by Hsee et al. worth passing on. They set up experiments in which people who voluntarily choose busyness report being happier than those who voluntarily choose idleness. Further, people who are forced into busyness report being happier than those who are forced into idleness. People choose to be idle if they do not have reason to be busy, but that even a specious justification can prompt them to seek busyness.  Here is their abstract:

There are many apparent reasons why people engage in activity, such as to earn money, to become famous, or to advance science. In this report, however, we suggest a potentially deeper reason: People dread idleness, yet they need a reason to be busy. Accordingly, we show in two experiments that without a justification, people choose to be idle; that even a specious justification can motivate people to be busy; and that people who are busy are happier than people who are idle. Curiously, this last effect is true even if people are forced to be busy. Our research suggests that many purported goals that people pursue may be merely justifications to keep themselves busy.

Their (slightly edited) speculations are interesting to read:

We speculate that the concurrent desires for busyness and for justification are rooted in evolution. In their strife for survival, human ancestors had to conserve energy to compete for scarce resources; expending energy without purpose could have jeopardized survival. With modern means of production, however, most people today no longer expend much energy on basic survival needs, so they have excessive energy, which they like to release through action. Yet the long-formed tendency to conserve energy lingers, making people wary of expending effort without purpose.

Our research also complements recent research of Airely et al.  that suggests that people work in order to search for meaning (i.e., achievement and recognition), our study suggests that people search for meaning in order to work. In Greek mythology, Sisyphus’ punishment, imposed by Zeus, was to eternally roll a rock toward the top of a hill, never to arrive there. The research of Ariely et al. predicts that Sisyphus would have been happier if Zeus had allowed the rock to reach the top of the hill and had then recognized Sisyphus’ achievement. Our research suggests that Sisyphus was better off with his punishment than he would have been with a punishment of an eternity of doing nothing, and that he might have chosen rolling a rock over idleness if he had been given a slight reason for doing it.

Idleness is potentially malignant. If idle people remain idle, they are miserable. If idle people become busy, they will be happier, but the outcome may or may not be desirable, depending on the value of the chosen activity. Busyness can be either constructive or destructive. Ideally, idle people should devote their energy to constructive courses, but it is often difficult to predict which actions are constructive (e.g., are business investments or scientific discoveries always constructive?), and not every idle individual is capable of constructive contributions. Idle people often engage in destructive busyness (from inner-city crimes to cross-border wars); as Hippocrates observed in Decorum, “Idleness and lack of occupation tend―nay are dragged―towards evil.”

We advocate a third kind of busyness: futile busyness, namely, busyness serving no purpose other than to prevent idleness. Such activity is more realistic than constructive busyness and less evil than destructive busyness. However, as we demonstrated in the no-justification (same-candy or same-design) condition of our research, most people will not voluntarily choose futile busyness.

This is where paternalism can play a role. For example, homeowners may increase the happiness of their idle housekeepers by letting in some mice and prompting the housekeepers to clean up. Governments may increase the happiness of idle citizens by having them build bridges that are actually useless. Indeed, some such interventions already exist: Airports have tried to increase the happiness (or reduce the unhappiness) of passengers waiting at the baggage carousel by increasing the distance between the gate and the baggage claim area, forcing them to walk far rather than wait idly. Similar intentions may be applied at the societal level. Although these strategies may not be ethical, we believe that futile busyness trumps both idleness and destructive busyness.

Mindblog on the road

I'm in Ft. Lauderdale today through next Tuesday, attending the 85th birthday party/piano concert David Goldberger, the fellow I did a four-hands concert with last March. This may have an effect on the frequency of next week's posts.

Acetaminophen (tylenol) reduces physical and social pain.

DeWall et al. show that an anti-pain medication that acts on the brain's pain pathways, reduces both physical and social pain:

Pain, whether caused by physical injury or social rejection, is an inevitable part of life. These two types of pain—physical and social—may rely on some of the same behavioral and neural mechanisms that register pain-related affect. To the extent that these pain processes overlap, acetaminophen, a physical pain suppressant that acts through central (rather than peripheral) neural mechanisms, may also reduce behavioral and neural responses to social rejection. In two experiments, participants took acetaminophen or placebo daily for 3 weeks. Doses of acetaminophen reduced reports of social pain on a daily basis. We used functional magnetic resonance imaging to measure participants’ brain activity, and found that acetaminophen reduced neural responses to social rejection in brain regions previously associated with distress caused by social pain and the affective component of physical pain (dorsal anterior cingulate cortex, anterior insula). Thus, acetaminophen reduces behavioral and neural responses associated with the pain of social rejection, demonstrating substantial overlap between social and physical pain.

A growing isolated brain can organize itself.

How much of the development of our brain's cortex depends on it being able to talk with other parts of the brain and body? Apparently, not as much as had been thought. Zhou et al. have used a mouse mutant in which the neocortex had been disconnected from the rest of the brain in order to analyze the development of the surface map (which might be compared to a geopolitical map supported by an infrastructure of shipping, communication, and regulatory networks). In normal mice, a few weeks of postnatal development complete the brain's organization; the mutant mice survive during this phase but die at about 3 weeks of age. During these weeks, the mutant mice, despite having disconnected brains, display a variety of behaviors: eating, drinking, walking, and swimming. Thus, "protomap" formation, namely cortical lamination and formation of areas, proceed normally in absence of extrinsic connections, but survival of projection neurons and acquisition of mature morphological and some electrophysiological features depend on the establishment of normal cortical–subcortical relationships.

Dopamine, Time, and Our Impulsivity

Yet another fascinating piece of work from the group around Ray Dolan at the London Wellcome Trust Center for Neuroimaging. They show that enhancing dopamine activity can increase our propensity to choose smaller–sooner over larger–later rewards:

Disordered dopamine neurotransmission is implicated in mediating impulsiveness across a range of behaviors and disorders including addiction, compulsive gambling, attention-deficit/hyperactivity disorder, and dopamine dysregulation syndrome. Whereas existing theories of dopamine function highlight mechanisms based on aberrant reward learning or behavioral disinhibition, they do not offer an adequate account of the pathological hypersensitivity to temporal delay that forms a crucial behavioral phenotype seen in these disorders. Here we provide evidence that a role for dopamine in controlling the relationship between the timing of future rewards and their subjective value can bridge this explanatory gap. Using an intertemporal choice task, we demonstrate that pharmacologically enhancing dopamine activity increases impulsivity by enhancing the diminutive influence of increasing delay on reward value (temporal discounting) and its corresponding neural representation in the striatum. This leads to a state of excessive discounting of temporally distant, relative to sooner, rewards. Thus our findings reveal a novel mechanism by which dopamine influences human decision-making that can account for behavioral aberrations associated with a hyperfunctioning dopamine system.

Motivating only half our bodies.

Schmidt et al. do a simple experiment to show that motivation need not be a person-level concept, our left and right hemispheres can be separately motivated:

Motivation is generally understood to denote the strength of a person’s desire to attain a goal. Here we challenge this view of motivation as a person-level concept, in a study that targeted subliminal incentives to only one half of the human brain. Participants in the study squeezed a handgrip to win the greatest fraction possible of each subliminal incentive, which materialized as a coin image flashed in one visual hemifield. Motivation effects (i.e., more force exerted when the incentive was higher) were observed only for the hand controlled by the stimulated brain hemisphere. These results show that in the absence of conscious control, one brain hemisphere, and hence one side of the body, can be motivated independently of the other.

The mind is the body - tumor suppression by enriched environment

An amazing article by Cao et al. brings home the intimate attachment between mental well-being and health - in mice (and by implication, for us too).   An enriched environment promotes formation of a nerve growth factor which in turn inhibits tumor growth through a series of biochemical steps, shown in the summary graphic before the abstract. A commentary by Jonah Lehrer notes that we need "a new metaphor for the interactions of the brain and body. They aren't simply connected via some pipes and tubes. They are emulsified together, so hopelessly intertwined that everything that happens in one affects the other. Holism is the rule."

Cancer is influenced by its microenvironment, yet broader, environmental effects also play a role but remain poorly defined. We report here that mice living in an enriched housing environment show reduced tumor growth and increased remission. We found this effect in melanoma and colon cancer models, and that it was not caused by physical activity alone. Serum from animals held in an enriched environment (EE) inhibited cancer proliferation in vitro and was markedly lower in leptin. Hypothalamic brain-derived neurotrophic factor (BDNF) was selectively upregulated by EE, and its genetic overexpression reduced tumor burden, whereas BDNF knockdown blocked the effect of EE. Mechanistically, we show that hypothalamic BDNF downregulated leptin production in adipocytes via sympathoneural β-adrenergic signaling. These results suggest that genetic or environmental activation of this BDNF/leptin axis may have therapeutic significance for cancer.

How superstition improves performance

Interesting stuff from Damish et al. They demonstrate a causal effect of an activated good-luck-associated superstition on subsequent performance (using things like 'lucky charms'). Participants for whom a superstition was activated performed better in various motor and cognitive tasks compared with participants for whom no such concept was activated. Second, they showed that these performance-enhancing effects are mediated by an increase in perceived level of self-efficacy. Activating a good-luck superstition leads to improved performance by boosting people’s belief in their ability to master a task. Here is their abstract:

Superstitions are typically seen as inconsequential creations of irrational minds. Nevertheless, many people rely on superstitious thoughts and practices in their daily routines in order to gain good luck. To date, little is known about the consequences and potential benefits of such superstitions. The present research closes this gap by demonstrating performance benefits of superstitions and identifying their underlying psychological mechanisms. Specifically, four different experiments show that activating good-luck-related superstitions via a common saying or action (e.g., “break a leg,” keeping one’s fingers crossed) or a lucky charm improves subsequent performance in golfing, motor dexterity, memory, and anagram games. Furthermore, they demonstrate that these performance benefits are produced by changes in perceived self-efficacy. Activating a superstition boosts participants’ confidence in mastering upcoming tasks, which in turn improves performance. Finally, they show that increased task persistence constitutes one means by which self-efficacy, enhanced by superstition, improves performance.

Behavioral economics as a palliative cop-out

Loewenstein and Ubel make some very simple and compelling points in their article on the use of behavioral economics to guide public policy and nudge people's behavior in desired directions. They note that behavioral economics is being used as a political expedient, allowing policymakers to avoid painful but more effective solutions rooted in traditional economics:

Take, for example, our nation’s obesity epidemic. The fashionable response, based on the belief that better information can lead to better behavior, is to influence consumers through things like calorie labeling — for instance, there’s a mandate in the health care reform act requiring restaurant chains to post the number of calories in their dishes...But studies of New York City’s attempt at calorie posting have found that it has had little impact on dieters’ choices...Obesity isn’t a result of a lack of information; instead, economists argue that rising levels of obesity can be traced to falling food prices, especially for unhealthy processed foods...To combat the epidemic effectively, then, we need to change the relative price of healthful and unhealthful food — for example, we need to stop subsidizing corn, thereby raising the price of high fructose corn syrup used in sodas, and we also need to consider taxes on unhealthful foods. But because we lack the political will to change the price of junk food, we focus on consumer behavior.

A “gallons-per-mile” bill recently passed by the New York State Senate is intended to help drivers think more clearly about the fuel consumption of the vehicles they purchase; research has shown that gallons-per-mile is a more effective means of getting drivers to appreciate the realities of fuel consumption than the traditional miles-per-gallon...But more and better information fails to get at the core of the problem: people drive large, energy-inefficient cars because gas is still relatively cheap. An increase in the gas tax that made the price of gas reflect its true costs would be a far more effective — though much more politically painful — way to reduce fuel consumption.

Thriving on selfishness

I enjoyed Marina Krakovsky's article in the April Scientific American on Omar Tonsi Eldakar's game theoretical take on why it pays for cheaters to punish other cheaters in maintaining the best balance between altruistic cooperators and defectors:

It’s the altruism paradox: If everyone in a group helps fellow members, everyone is better off—yet as more work selflessly for the common good, cheating becomes tempting, because individuals can enjoy more personal gain if they do not chip in. But as freeloaders exploit the do-gooders, everybody’s payoff from altruism shrinks.

All kinds of social creatures, from humans down to insects and germs, must cope with this problem; if they do not, cheaters take over and leech the group to death. So how does altruism flourish? Two answers have predominated over the years: kin selection, which explains altruism toward genetic relatives—and reciprocity—the tendency to help those who have helped us. Adding to these solutions, evolutionary biologist Omar Tonsi Eldakar came up with a clever new one: cheaters help to sustain altruism by punishing other cheaters, a strategy called selfish punishment.

“All the theories addressed how altruists keep the selfish guys out,” explains Eldakar, who described his model with his Ph.D. thesis adviser David Sloan Wilson of Binghamton University in May 2008. Because selfishness undermines altruism, altruists certainly have an incentive to punish cheaters—a widespread behavior pattern known as altruistic punishment. But cheaters, Eldakar realized, also have reason to punish cheaters, only for motives of their own: a group with too many cheaters does not have enough altruists to exploit. As Eldakar puts it, “If you’re a single selfish individual in a group of altruists, the best thing you can do evolutionarily is to make sure nobody else becomes selfish—make sure you’re the only one.” That is why, he points out, some of the harshest critics of sports doping, for example, turn out to be guilty of steroid use themselves: cheating gives athletes an edge only if their competitors aren’t doing it, too.

Although it is hypocritical for cheaters to punish other cheaters, members of the group do not balk as long as they benefit. And when selfish punishment works well, benefit they do. In a colony of tree wasps (where workers care for the queen’s offspring instead of laying their own eggs), a special caste of wasps sting other worker wasps that try to lay eggs, even as the vigilante wasps get away with laying eggs themselves. In a strange but mutually beneficial bargain, punishing other cheaters earns punishers the right to cheat.

In the year since Eldakar and Wilson wrote up their analysis, their insights have remained largely under the radar. But the idea of a division of labor between cooperators and policing defectors appeals to Pete Richerson, who studies the evolution of cooperation at the University of California, Davis. “It’s nothing as complicated as a salary, but allowing the punishers to defect in effect does compensate them for their services in punishing other defectors who don’t punish,” he says. After all, policing often takes effort and personal risk, and not all altruists are willing to bear those costs.

Corrupt policing may evoke images of the mafia, and indeed Eldakar notes that when the mob monopolizes crime in a neighborhood, the community is essentially paying for protection from rival gangs—a deal that, done right, lowers crime and increases prosperity. But mob dynamics are not always so benign, as the history of organized crime reveals. “What starts out as a bunch of goons with guns willing to punish people [for breaching contracts] becomes a protection racket,” Richerson says. The next question, therefore, is, What keeps the selfish punishers themselves from overexploiting the group?

Wilson readily acknowledges this limitation of the selfish punishment model. Although selfish punishers allow cooperators to gain a foothold within a group, thus creating a mix of cheaters and cooperators, “there’s nothing telling us that that mix is an optimal mix,” he explains. The answer to that problem, he says, is competition not between individuals in a group but between groups. That is because whereas selfishness beats altruism within groups, altruistic groups are more likely to survive than selfish groups. So although selfish punishment aids altruism from within a group, the model also bolsters the idea of group selection, a concept that has seen cycles of popularity in evolutionary biology.

What is more, altruism sometimes evolves without selfish punishment. In a software simulation, Eldakar and Wilson have found that as the cost of punishing cheaters falls, so do the number of selfish punishers. “When punishment is cheap, lots of people punish,” Wilson explains. And among humans, there is no shortage of low-cost ways to keep others in line—from outright ostracism to good old-fashioned gossip.

Moral evaluations influence our mental state ascriptions.

Gilbert Chin, in the "Editor's Choice" section of Science, gives a nice summary of work by Uttich and Lombrozo in their Cognition article:

A robust phenomenon established empirically during the past decade is the tendency of observers to regard morally bad consequences (such as harm to the environment) that occur as a secondary effect of actions taken by an agent (such as a corporate CEO) in the course of achieving the primary effect—an increase in revenue—as having been committed intentionally. In contrast, morally good consequences in a similar scenario are judged as being incidental. A number of explanations for this asymmetry (also known as the Knobe effect) have been put forth; most prominent, perhaps, is the proposal that the moral valence of the side effect alters the observer's inference about the agent's mental state; that is, whether the CEO acted with intent. Uttich and Lombrozo bring to bear a series of vignettes in which the type of social norm (moral versus conventional), the kind of behavior (norm-conforming versus norm-violating), and the outcome valence (helpful versus harmful) were varied independently. Their results support a "rational scientist" framework, so that the observer's computation of the agent's state of mind weights actions that flout commonly accepted rules of behavior as being more informative and hence diagnostic of intentionality than conformist ones.

Here is the abstract from the article:

Theory of mind, the capacity to understand and ascribe mental states, has traditionally been conceptualized as analogous to a scientific theory. However, recent work in philosophy and psychology has documented a “side-effect effect” suggesting that moral evaluations influence mental state ascriptions, and in particular whether a behavior is described as having been performed ‘intentionally.’ This evidence challenges the idea that theory of mind is analogous to scientific psychology in serving the function of predicting and explaining, rather than evaluating, behavior. In three experiments, we demonstrate that moral evaluations do inform ascriptions of intentional action, but that this relationship arises because behavior that conforms to norms (moral or otherwise) is less informative about underlying mental states than is behavior that violates norms. This analysis preserves the traditional understanding of theory of mind as a tool for predicting and explaining behavior, but also suggests the importance of normative considerations in social cognition.

How exercise stimulates brain nerve cell growth

Human and animal brains produce new brain cells (neurogenesis), and exercise increases this process. Gretchen Reynolds reviews work of Cage and others suggesting a mechanism for how this works: exercise lowers the levels of a protein (BMP, or bone morphogenetic protein) that suppresses nerve cell division in the hippocampus.