Friday, July 30, 2010

Resilience in the face of adversity - brain correlates

Interesting work from Dolan's group on how we modulate expected aversive outcomes:
The value assigned to aversive events is susceptible to contextual influences. Here, we asked whether a change in the valuation of negative events is reflected in an altered neuronal representation of their expected aversive outcome. We show that experiencing an aversive event in the past, and choosing to experience it in the future, reduces its aversive value. This psychological change is mirrored in an altered neural representation of aversive value in the caudate nucleus and anterior cingulate cortex. Our findings indicate that subcortical regions known to track expected value such as the caudate nucleus, together with anterior cingulate cortical regions implicated in emotional modulation, mediate a revaluation in expectancies of aversive states. The results provide a striking example of a contextual sensitivity in how the brain ascribes value to events, in a manner that may foster resilience in the face of adversity.

Reciprocity engages our brain's reward system.

Interesting stuff from Phan et al:
Brain reward circuitry, including ventral striatum and orbitofrontal cortex, has been independently implicated in preferences for fair and cooperative outcomes as well as learning of reputations. Using functional MRI (fMRI) and a “trust game” task involving iterative exchanges with fictive partners who acquire different reputations for reciprocity, we measured brain responses in 36 healthy adults when positive actions (entrust investment to partners) yield positive returns (reciprocity) and how these brain responses are modulated by partner reputation for repayment. Here we show that positive reciprocity robustly engages the ventral striatum and orbitofrontal cortex. Moreover, this signal of reciprocity in the ventral striatum appears selectively in response to partners who have consistently returned the investment (e.g., a reputation for reciprocity) and is absent for partners who lack a reputation for reciprocity. These findings elucidate a fundamental brain mechanism, via reward-related neural substrates, by which human cooperative relationships are initiated and sustained.

Thursday, July 29, 2010


Here is a cute study that attempts to gauge  our mood (more accurately, the 7% of American who use Twitter) throughout the day.  Play through the video that shows regional and time of day differences.  From the quickie NYTimes mention of the work: "you’re probably happiest in the morning and least satisfied about noon. Analyzing words in those posts, researchers found that Thursday is the saddest day; Sunday, the happiest. People on the West Coast who post are happier than their counterparts on the East Coast. The moods were mapped, showing happy times (greener areas) and unhappy (red areas)."

Altruism as good business - shoppers who care

Gneezy et al. add an interesting twist to studies of how we buy things. Companies loose money in attempts to enhance sales with pay-what-you-want pricing, and adding a charitable contribution to standard pricing has little effect. However, in a variation of pay-what-you-want with half going to charity, a more reasonable profit was returned. (It is not clear whether the charitable giving by the company generated additional generosity by the consumer or created additional social pressure.)
A field experiment (N = 113,047 participants) manipulated two factors in the sale of souvenir photos. First, some customers saw a traditional fixed price, whereas others could pay what they wanted (including $0). Second, approximately half of the customers saw a variation in which half of the revenue went to charity. At a standard fixed price, the charitable component only slightly increased demand, as similar studies have also found. However, when participants could pay what they wanted, the same charitable component created a treatment that was substantially more profitable. Switching from corporate social responsibility to what we term shared social responsibility works in part because customized contributions allow customers to directly express social welfare concerns through the purchasing of material goods.

Wednesday, July 28, 2010

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.

Tuesday, July 27, 2010

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.):

Monday, July 26, 2010

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:

MRI evidence on how hypnosis works.

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.

Friday, July 23, 2010

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.

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.

Thursday, July 22, 2010

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:

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.

Wednesday, July 21, 2010

Acetaminophen (tylenol) reduces physical and social 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.

Tuesday, July 20, 2010

Dopamine, Time, and Our Impulsivity


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.

Monday, July 19, 2010

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."


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.

Friday, July 16, 2010

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:


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:


“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?


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.

Thursday, July 15, 2010

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. 

Wednesday, July 14, 2010

Factoids about aging, reaching 70

Studies suggest that aging brings a more settled and calm view of what one is, and what one is not, and a general increase in contentment. They also point to the sobering point that attentional and executive functions of one's brain apparently move (retreat) to more frontal brain structures, perhaps reflecting the increased effort and focus being required to hold things together, leaving behind fading richer and younger limbic and lower brain autopilots that once were more open to, and could juggle with, many novel contexts and feelings.

Just to keep current my list of the general litany of degenerative changes that can be observed on aging (present company excepted, of course), I thought I would point to this article from this past Sunday's NYTimes.   Kate Zernike writes about turning 70, a recent transition for Ringo Starr who gave himself a 70th birthday concert at Radio City Music Hall (it happens to me in two years).   I was most fascinated (and sobered) by what entering the +70 club gets you. I've rearranged part of their graphic to summarize some of the numbers:

A sinister bias in calling football (soccer) fouls


Tuesday, July 13, 2010

The benefits of 'losing it'

Benedict Carey does an interesting article on the personal and social utility of letting out, expressing, strong spontaneous emotional reactions.   President Obama's failure to do this has led people to question his sincerity or commitment to fixing financial institutions or oil spills. This is line with Pinker's argument that emotions evolved as guarantors or our authenticity.  Such authenticity is the issue in Obama's failure to emote. A few clips:
...people develop a variety of psychological tools to manage what they express in social situations, and those techniques often become subconscious, affecting interactions in unintended ways. The better that people understand their own patterns, the more likely they are to see why some emotionally charged interactions go awry — whether from too little control or, in the president’s case, perhaps too much.

Psychologists divide regulation strategies into two broad categories: pre-emptive, occurring before an emotion is fully felt; and responsive, coming afterward... Suppression, while clearly valuable in some situations (no laughing at funerals, please), has social costs that are all too familiar to those who know its cold touch.

Pre-emptive techniques can work in more subtle ways. One of these is simple diversion, reflexively focusing on the good and ignoring the bad — rereading the praise in an evaluation and ignoring or dismissing any criticism. A 2009 study...found that people over 55 were much more likely than those aged 25 and under to focus on positive images when in a bad mood — thereby buoying their spirits. The younger group was more likely to focus on negative images when feeling angry or down... older people were twice as likely as younger ones to be “rapid regulators” — people whose mood bounced back quickly, sometimes within minutes, after ruminating on depressing memories...older people tend to regulate their emotions faster, and are not as motivated to explore negative information, to engage negative images, as younger people are...And it makes some sense that younger adults would explore the negative side of things, that they need to and maybe want to experience them to experience life as they develop their own strategies to regulate...the ability to shrug off feelings of disgust or outrage may suit an older group but strike younger people as inauthentic, even callous.

Music sightreading skill - practice doesn't make perfect


Monday, July 12, 2010

Goal pursuit outside our conscious awareness

Custer and Aarts expand on a favorite topic of mine (see the "I-Illusion" podcast in the left column): how our sense of authorship and agency is an illusion. They review research demonstrating that goals and the motivation to pursue them can arise unconsciously, and propose a mechanism for how this may happen. Here is a mix of their abstract, text clips, and a proposed mechanism:
People often act in order to realize desired outcomes, or goals. Although behavioral science recognizes that people can skillfully pursue goals without consciously attending to their behavior once these goals are set, conscious will is considered to be the starting point of goal pursuit. Indeed, when we decide to work hard on a task, it feels as if that conscious decision is the first and foremost cause of our behavior. That is, we are likely to say, if asked, that the decision to act produced the actions themselves. Recent discoveries, however, challenge this causal status of conscious will. They demonstrate that goals themselves can arise and operate unconsciously - actions are initiated even though we are unconscious of the goals to be attained or their motivating effect on our behavior. Social situations and stimuli in the surroundings activate or prime goals in our minds outside of our awareness, thereby motivating and guiding us.

Figure - The proposed mechanism for unconscious goal pursuit.
Experiments compatible with this model:
Neuroimaging research has discovered that reward cues are processed by limbic structures such as the nucleus accumbens and the ventral striatum. These subcortical areas play a central role in determining the rewarding value of outcomes and are connected to frontal areas in the cortex that facilitate goal pursuit. These reward centers in the brain respond to evolutionarily relevant rewards such as food and sexual stimuli, but also to learned rewards (such as money or status), or words (such as good or nice) that are associated with praise or rewards. This demonstrates that regardless of their shape or form, such positive stimuli induce a reward signal that is readily picked up by the brain.

Other recent research has demonstrated that subliminal primes that are specifically related to rewards can motivate people to increase the effort they invest in behaviors. In one study, participants could earn money by squeezing a handgrip. Before each squeeze, the money that could be earned was indicated by a 1-pound or 1-penny coin on the screen. Whereas on some trials the coin was clearly visible, on others it was presented subliminally. Thus, effects of conscious and unconscious reward cues could be compared within one experiment. It was found that people squeezed harder on high than on low reward trials, regardless of whether the reward was consciously visible or not. Moreover, this effect was accompanied by activation in the brain areas that play a role in reward processing and the recruitment of effort for action…These findings indicate that conscious and unconscious reward cues have similar effects on effort and flexible cognitive processing, which suggests that conscious awareness of rewards is not needed for goal pursuit to occur.

A smooth botox face inhibits emotion processing

Richie Davidson and collaborators at Wisconsin come up with this interesting gem, on the consequences of a face made more smooth and beautiful by Botulinum toxin injections:
How does language reliably evoke emotion, as it does when people read a favorite novel or listen to a skilled orator? Recent evidence suggests that comprehension involves a mental simulation of sentence content that calls on the same neural systems used in literal action, perception, and emotion. In this study, we demonstrated that involuntary facial expression plays a causal role in the processing of emotional language. Subcutaneous injections of botulinum toxin-A (BTX) were used to temporarily paralyze the facial muscle used in frowning. We found that BTX selectively slowed the reading of sentences that described situations that normally require the paralyzed muscle for expressing the emotions evoked by the sentences. This finding demonstrates that peripheral feedback plays a role in language processing, supports facial-feedback theories of emotional cognition, and raises questions about the effects of BTX on cognition and emotional reactivity. We account for the role of facial feedback in language processing by considering neurophysiological mechanisms and reinforcement-learning theory.

Friday, July 09, 2010

The reading module of our brains.

I’ve been meaning to mention an excellent article by Oliver Sachs in the June 28 issue of The New Yorker “A man of letters”. It describes a class of stroke patients who selectively loose the ability to read letters, frequently seeing them as some kind of foreign gibberish, yet can still write (“alexia sine agraphia”). In this article, unlike some of his others which have frustrated me by not getting down to the brain basics, he give an excellent summary of how it is that our brains come to have a specialized module for a skilled activity that was invented only ~5,000 years ago, less than an eye blink in evolutionary time. Here is my editing of chunks that give the bottom line:
There may be objects that are recognized at birth, such as faces, but beyond this the world of objects must be learned through experience and activity: looking, touching, handling, correlating the feel of objects with their appearance...Visual object recognition depends on the inferotemporal cortex..where neuronal function is very plastic...Mark Changizi and colleagues at Caltech, from examining more than a hundred ancient and modern writing systems, have shown that all of them, while geometrically very different, share certain basic topological similarities...which resemble topological invariants in a range of natural settings, leading them to hypothesize that the shapes of letters "have been selected to resemble the conglomeration of contours found in natural scenes, thereby tapping into our already-existing object recognition mechanisms."

The origin of writing and reading cannot be understood as a direct evolutionary adaptation. It is dependent on the plasticity of the brain, and on the fact that, even within the small span of a human lifetime, experience - experiential selection - is as powerful an agent of change as natural selection... We are literate not by virtue of a divine intervention (which Alfred Russel Wallace proposed, contra Darwin) but through a cultural invention and a cultural selection that make a brilliant and creative new use of a preexisting neural proclivity.

Physical contact and financial risk taking

Interesting observations from Levav and Argo:

Thursday, July 08, 2010

Mind reading - How to seem telepathic

Here I attempt to summarize  an article by Eyai and Epley (on enabling mind reading by matching construal levels) by patching together bits of abstract and body text.  The results make the point that accurately reading other minds to know how one is evaluated by others—or how others evaluate themselves—requires focusing one’s evaluative lens at the right level of detail:
People can have difficulty intuiting what others think about them at least partly because people evaluate themselves in more fine-grained detail than observers do. This mismatch in the level of detail at which people construe themselves versus others diminishes accuracy in social judgment. Being a more accurate mind reader requires thinking of oneself at a higher level of construal that matches the observer’s construal (Experiments 1 and 2)*, and this strategy is shown in a further experiment (experiment 4**) to be more effective in this context than perspective taking (putting oneself in other people's shoes).

*Experiment 1 involved predicting judgements of attractiveness. This experiment found subjects to be more accurate in intuiting how attractive they will be judged (by others viewing a recent photo of themselves) in the distant future than in the near future. Experiment 2 involved predicting overall impression of oneself that observers would gain from listening (in the near versus distant future) to a recording they made on various topics. Again, predictions were more accurate for the imagined distant future. Thus altering construal level (near versus distant future) can increase accuracy in two very common and important instances of mind reading in everyday life—intuiting how attractively one will be evaluated by others and intuiting others’ overall impressions of oneself.

Accurately intuiting how others evaluate themselves requires the opposite strategy—thinking about others in a lower level of construal that matches the way people evaluate themselves. **In Experiment 4, University of Chicago undergraduates (N = 62) participated in a procedure similar to that of Experiment 1, except that targets rated how attractive they found themselves, using a scale ranging from 1 (not at all) to 9 (very), and observers received the construal manipulation. Observers were told that the pictures were taken earlier in the day (near condition) or a few months earlier (distant condition), and rated how attractive they thought the targets found themselves to be, using the same scale. Observers were more accurate in the near than in the distant condition.

How our brains resolve competing social signals

Zaki et al. suggest that that two systems that have been the subject of numerous MindBlog posts — the mirror neuron system (MNS) and mental state attribution system (MSAS)— are specialized for processing nonverbal and contextual social cues, respectively, and support the resolution of incongruent social cues (such as facial expression conflicting with verbal content of a message).
...we predicted that these control systems would help resolve conflict by "biasing" processing toward domain-specific neural systems involved in responding to social cues deemed to be task relevant, as reflected in perceivers' behavioral reliance on a given cue type when rating target affect. On the one hand, to the extent that perceivers behaviorally rely on nonverbal cues, biasing could increase activity in regions responsible for processing such cues, including premotor and parietal regions comprising the putative mirror neuron system (MNS). On the other hand, to the extent that perceivers deem contextual cues more relevant, processing could be biased toward systems implicated in drawing inferences about non-observable mental states such as beliefs, including the medial prefrontal, posterior cingulate, temporopolar, and temporoparietal regions comprising the mental state attribution system (MSAS). Because these systems are functionally dissociable and may in some cases inhibit each other, they are strong candidate targets for the effects of social cognitive conflict resolution.
From their abstract:
Cognitive control mechanisms allow individuals to behave adaptively in the face of complex and sometimes conflicting information. Although the neural bases of these control mechanisms have been examined in many contexts, almost no attention has been paid to their role in resolving conflicts between competing social cues, which is surprising given that cognitive conflicts are part of many social interactions. Evidence about the neural processing of social information suggests that two systems—the mirror neuron system (MNS) and mental state attribution system (MSAS)—are specialized for processing nonverbal and contextual social cues, respectively. This could support a model of social cognitive conflict resolution in which competition between social cues would recruit domain-general cognitive control mechanisms, which in turn would bias processing toward the MNS or MSAS. Such biasing could also alter social behaviors, such as inferences made about the internal states of others. We tested this model by scanning participants using functional magnetic resonance imaging while they drew inferences about the social targets' emotional states based on congruent or incongruent nonverbal and contextual social cues. Conflicts between social cues recruited the anterior cingulate and lateral prefrontal cortex, brain areas associated with domain-general control processes. This activation was accompanied by biasing of neural activity toward areas in the MNS or MSAS, which tracked, respectively, with perceivers' behavioral reliance on nonverbal or contextual cues when drawing inferences about targets' emotions. Together, these data provide evidence about both domain-general and domain-specific mechanisms involved in resolving social cognitive conflicts.
Figure: The presence of social cognitive response conflict (i.e., the comparison of incongruent vs congruent trials) recruited activity in several regions associated with domain-general conflict monitoring and control, including the anterior cingulate cortex, right ventrolateral prefrontal cortex, right middle frontal gyrus, and posterior dorsomedial prefrontal cortex

Wednesday, July 07, 2010

The virtues of a wandering mind.

John Tierney's article on possible uses of mind wandering is worth reading. During our waking hours our minds seem to wander about 30% of the time.  One suggestion is that:
...There’s an evolutionary advantage to the brain’s system of mind wandering...While a person is occupied with one task, this system keeps the individual’s larger agenda fresher in mind...It thus serves as a kind of reminder mechanism, thereby increasing the likelihood that the other goal pursuits will remain intact and not get lost in the shuffle of pursuing many goals.
...Where exactly does the mind go during those moments? By observing people at rest during brain scans, a “default network” that is active when people’s minds are especially free to wander has been identified. When people do take up a task, the brain’s executive network lights up to issue commands, and the default network is often suppressed....But during some episodes of mind wandering, both networks are firing simultaneously...Why both networks are active is up for debate. One school theorizes that the executive network is working to control the stray thoughts and put the mind back on task...Another school of psychologists..theorizes that both networks are working on agendas beyond the immediate task. That theory could help explain why studies have found that people prone to mind wandering also score higher on tests of creativity.
Smilek et al., by the way, note that mind wandering can be assayed by observing blinking: during an extended period of reading, episodes of mind wandering, compared with on-task periods, contain more eye closures (blinks) and fewer fixations on the text ― even as subjects continue to scan the text.

Brain correlates of behavioral traits


Tuesday, July 06, 2010

Being calmed by a machine.

I was initially repelled by the prospect, noted in this article, of a future in which robotic animals are routinely used to sooth disoriented and distressed patients - but then thought “Hey, if there is not another human around to do the job, why object if an machine can provide neotenous (cute baby like) stimuli that dampen amygdala and sympathetic nervous system arousal.

Wealth diminishes our ability to savor the ordinary

Quoidbach et al. test
...what Gilbert has termed the experience-stretching hypothesis, that experiencing the best things in life — such as surfing Oahu’s famous North Shore or dining at Manhattan’s four-star restaurant Daniel — may actually mitigate the delight one experiences in response to the more mundane joys of life, such as sunny days, cold beers, and chocolate bars.
Their abstract:

Monday, July 05, 2010

Brain imaging can predict behavior days in advance.

Falk et al. find a brain region that seems to make a more reliable report of people's intentions than their self-reported attitudes and intentions. (It does seems a bit spooky when a machine reports what we are going to do more accurately than we can.)  The medial prefrontal regions which were predictive of behavior are ones I've mentioned in a previous post that predict spontaneous motor behavior several seconds before reportable motor intentions form.  The authors measured neural activity while people were exposed to persuasive messages regarding the value of regular sunscreen use, and then used those values to predict future behavior change in the same individuals (i.e., increased sunscreen use. Successful persuasion-induced behavior change had been observed in this domain in several previous studies.)  The relevant medial prefrontal regions:
..are reliably coactivated across a host of "self" processes.....[and]  have been previously observed in multiple studies of persuasion and attitude change.. .indicating that these regions may be involved in the formation of behavioral intentions that are not accessible to conscious self-report.
Here is a figure and their abstract:

Regions associated with behavior change in a whole brain analysis. These regions have been observed as predictors of spontaneous motor behavior, before and independent of consciously reportable behavioral intentions.
Although persuasive messages often alter people's self-reported attitudes and intentions to perform behaviors, these self-reports do not necessarily predict behavior change. We demonstrate that neural responses to persuasive messages can predict variability in behavior change in the subsequent week. Specifically...a ..region of medial prefrontal cortex .. was reliably associated with behavior change...activity in this region predicted an average 23% of the variance in behavior change beyond the variance predicted by self-reported attitudes and intentions. Thus, neural signals can predict behavioral changes that are not predicted from self-reported attitudes and intentions alone. Additionally, this is the first functional magnetic resonance imaging study to demonstrate that a neural signal can predict complex real world behavior days in advance.

What we touch influences social judgements.

Here is another example of "embodied cognition"- how our physical environment can influence our thinking. In a previous post I mentioned studies showing that simply holding a warm cup of coffee prompts us to view others as emotionally warmer. And, in another post, I pointed to a study that found that holding a heavy clipboard makes us perceive social-justice issues as more important. Now Ackerman et al. ..(reviewed in ScienceNow).. expand on these studies to note that simply running your hand over sandpaper may make you view social interactions as more hostile and competitive.
Touch is both the first sense to develop and a critical means of information acquisition and environmental manipulation. Physical touch experiences may create an ontological scaffold for the development of intrapersonal and interpersonal conceptual and metaphorical knowledge, as well as a springboard for the application of this knowledge. In six experiments, holding heavy or light clipboards, solving rough or smooth puzzles, and touching hard or soft objects nonconsciously influenced impressions and decisions formed about unrelated people and situations. Among other effects, heavy objects made job candidates appear more important, rough objects made social interactions appear more difficult, and hard objects increased rigidity in negotiations. Basic tactile sensations are thus shown to influence higher social cognitive processing in dimension-specific and metaphor-specific ways.

Friday, July 02, 2010

More on enhanced brain processes in musicians.

From Pallesen et al.:
Musical competence may confer cognitive advantages that extend beyond processing of familiar musical sounds. Behavioural evidence indicates a general enhancement of both working memory and attention in musicians. It is possible that musicians, due to their training, are better able to maintain focus on task-relevant stimuli, a skill which is crucial to working memory. We measured the blood oxygenation-level dependent (BOLD) activation signal in musicians and non-musicians during working memory of musical sounds to determine the relation among performance, musical competence and generally enhanced cognition. All participants easily distinguished the stimuli. We tested the hypothesis that musicians nonetheless would perform better, and that differential brain activity would mainly be present in cortical areas involved in cognitive control such as the lateral prefrontal cortex. The musicians performed better as reflected in reaction times and error rates. Musicians also had larger BOLD responses than non-musicians in neuronal networks that sustain attention and cognitive control, including regions of the lateral prefrontal cortex, lateral parietal cortex, insula, and putamen in the right hemisphere, and bilaterally in the posterior dorsal prefrontal cortex and anterior cingulate gyrus. The relationship between the task performance and the magnitude of the BOLD response was more positive in musicians than in non-musicians, particularly during the most difficult working memory task. The results confirm previous findings that neural activity increases during enhanced working memory performance. The results also suggest that superior working memory task performance in musicians rely on an enhanced ability to exert sustained cognitive control. This cognitive benefit in musicians may be a consequence of focused musical training.

How we learn skilled motor sequences

Because I am a pianist, I found the following bit from Steele and Penhune to be interesting and relevant. They found that:
Performance was separated into two components: accuracy (the more explicit, rapidly learned, stimulus–response association component) and synchronization (the more procedural, slowly learned component).
Here is their whole abstract:
Our capacity to learn movement sequences is fundamental to our ability to interact with the environment. Although different brain networks have been linked with different stages of learning, there is little evidence for how these networks change across learning. We used functional magnetic resonance imaging to identify the specific contributions of the cerebellum and primary motor cortex (M1) during early learning, consolidation, and retention of a motor sequence task. Performance was separated into two components: accuracy (the more explicit, rapidly learned, stimulus–response association component) and synchronization (the more procedural, slowly learned component). The network of brain regions active during early learning was dominated by the cerebellum, premotor cortex, basal ganglia, presupplementary motor area, and supplementary motor area as predicted by existing models. Across days of learning, as performance improved, global decreases were found in the majority of these regions. Importantly, within the context of these global decreases, we found specific regions of the left M1 and right cerebellar VIIIA/VIIB that were positively correlated with improvements in synchronization performance. Improvements in accuracy were correlated with increases in hippocampus, BA 9/10, and the putamen. Thus, the two behavioral measures, accuracy and synchrony, were found to be related to two different sets of brain regions—suggesting that these networks optimize different components of learning. In addition, M1 activity early on day 1 was shown to be predictive of the degree of consolidation on day 2. Finally, functional connectivity between M1 and cerebellum in late learning points to their interaction as a mechanism underlying the long-term representation and expression of a well learned skill.

Thursday, July 01, 2010

More on testosterone and human trust.

Johnson and Breedlove offer a commentary on work by Bos et al. mentioned in my June 11 post. They note that:
Women who were already skeptical in their judgment of trustworthy faces did not change their judgment under the influence of testosterone (T). Rather, it was the 12 women who gave the highest ratings of trust under placebo who became significantly more skeptical after T treatment...Because endogenously produced T levels normally vary across time, these findings ... raise the question of whether fluctuating androgen secretion may normally modulate a person’s judgment of whether to trust people. There are circadian rhythms in T secretion, in both men and women, so is there also a circadian rhythm in how they judge trustworthiness in faces? There is also variation in circulating T in women across the menstrual cycle, with a modest peak in circulating T just a few days before ovulation, the very period during which copulation is most likely to result in pregnancy. What’s more, androgens such as T have been reported to boost women’s libido in several studies, including one study using the same sublingual dose of T, which increased sexual arousal. If androgens normally boost female libido, a peak in T before ovulation makes sense to evolutionary psychologists who might expect women to be most interested in sex when they are most fertile. What the present findings suggest is that women might also reach their peak in skepticism about the trustworthiness of other people, presumably including potential mates, at about this same point in the ovulatory cycle. Heightened skepticism about a potential mate’s trustworthiness also makes evolutionary sense in scenarios where a father’s ongoing support is crucial for survival of the infant.
The review also speculates on where T may be acting in the brain:
...the amygdala has been implicated in many studies of social judgment, including making judgments about other people’s faces, and it is also a hotspot for neurons expressing the androgen receptors that T acts upon to regulate gene expression (14, 15). Thus, it is possible that T may alter social judgments by acting directly on the amygdala, perhaps, the authors suggest, by regulating the strength of signaling between the amygdala and other brain regions implicated in social evaluation, such as the orbitofrontal cortex.

Figure - Potential model for hormonal effects on interpersonal trust. The amygdala (center) is active during fearful responses or detecting threat in faces, and many neurons there possess androgen receptors, enabling them to respond to T. Bos et al. (4) suggest that T may reduce interpersonal trust by acting on vasopressinergic neurons in the amygdala to increase communication to brainstem systems that activate fearful responses, while reducing communication to orbitofrontal cortex. Oxytocin boosts interpersonal trust, perhaps by exerting opposing effects on these same systems.

Prefrontal Reward Prediction Errors in Alcohol Dependence

Park et al. (in a collaboration involving, once again,  Ray Dolan at University College) find abnormal functional connectivity between striatum and dorsolateral prefrontal cortex in alcohol-dependent patients.
Patients suffering from addiction persist in consuming substances of abuse, despite negative consequences or absence of positive consequences. One potential explanation is that these patients are impaired at flexibly adapting their behavior to changes in reward contingencies. A key aspect of adaptive decision-making involves updating the value of behavioral options. This is thought to be mediated via a teaching signal expressed as a reward prediction error (PE) in the striatum. However, to exert control over adaptive behavior, value signals need to be broadcast to higher executive regions, such as prefrontal cortex. Here we used functional MRI and a reinforcement learning task to investigate the neural mechanisms underlying maladaptive behavior in human male alcohol-dependent patients. We show that in alcohol-dependent patients the expression of striatal PEs is intact. However, abnormal functional connectivity between striatum and dorsolateral prefrontal cortex (dlPFC) predicted impairments in learning and the magnitude of alcohol craving. These results are in line with reports of dlPFC structural abnormalities in substance dependence and highlight the importance of frontostriatal connectivity in addiction, and its pivotal role in adaptive updating of action values and behavioral regulation. Furthermore, they extend the scope of neurobiological deficits underlying addiction beyond the focus on the striatum.