Monday, January 31, 2011

Modern conversation.

As relevant to this morning's previous post, I had to pass on today's Doonesbury cartoon, having noted during my kid's New Year's visit how our conversations transitioned seamlessly from periods of actual talking to tapping on our iPhones and back to talking again, no requirement that one excuse oneself from actual talk, the accepted procedure was just to suddenly divert attention and start tapping on the new prosthetic device. This clearly is how the world of 20- and 30-somethings now works.

Is our technology replacing our identity?

After publishing an optimistic book about the internet in 1995 ("Life on the Screen"), MIT social science professor Sherry Turkle has now written a darker tome, "Alone Together,"  worrying that we are moving more of our lives online and away from real physical human contacts. The first half of the book is about social robots. From Jonah Lehrer's review:

“Dependence on a robot presents itself as risk free,” Turkle writes. “But when one becomes accustomed to ‘companionship’ without demands, life with people may seem overwhelming.” A blind date can be a fraught proposition when there’s a robot at home that knows exactly what we need. And all she needs is a power outlet...The reason robots are such a slippery slope, according to Turkle, is that they take advantage of a deeply human instinct. When it comes to the perception of other minds, we are extremely gul­lible, bestowing agency on even the most inanimate of objects.
The second part of the book deals with Turkle's concern that the internet is becoming our way of being with other people, in a style that turns them into objects. (Why did I just text my friend instead of actually just calling and talking with him.)
...the online world is no longer a space of freedom and re­invention. Instead, we have been trapped by Facebook profiles and Google cache, in which verbs like “delete” and “erase” are mostly metaphorical...We aren’t “happy” anymore: we’re simply a semicolon followed by a parenthesis. Instead of talking on the phone, we send a text; instead of writing wistful letters, we edit our Tumblr blog...these obvious objections shouldn’t obscure the real mystery: If the Internet is such an alienating force, then why can’t we escape it? If Facebook is so insufferable, then why do hundreds of millions of people check their page every day?
My own experience is that my participation in social web sites has broadened my world of real world contacts and friends, as noted by Lehrer:
...despite our misgivings about the Internet, its effects on real-life relationships seem mostly positive, if minor. A 2007 study at Michigan State University involving 800 undergraduates, for instance, found that Facebook users had more social capital than abstainers, and that the site increased measures of “psychological well-being,” especially in those suffering from low self-esteem. Other studies have found that frequent blogging leads to increased levels of social support and integration and may serve as “the core of building intimate relationships.” One recurring theme to emerge from much of this research is that most people, at least so far, are primarily using the online world to enhance their offline relationships, not supplant them.

Friday, January 28, 2011

Our social brain - what are smiles for?

In this past Tuesday's NYTimes science section, Carl Zimmer offers a brief review of some of the many social functions served by our smiling at each other (signaling happiness, social bonding, embarrassment, dominance, etc.). He focuses on the work of Paula Niedenthal. I found this particular bit interesting:

In one study, she and her colleagues are testing the idea that mimicry lets people recognize authentic smiles. They showed pictures of smiling people to a group of students. Some of the smiles were genuine and others were fake. The students could readily tell the difference between them....Then Dr. Niedenthal and her colleagues asked the students to place a pencil between their lips. This simple action engaged muscles that could otherwise produce a smile. Unable to mimic the faces they saw, the students had a much harder time telling which smiles were real and which were fake.

The scientists then ran a variation on the experiment on another group of students. They showed the same faces to the second group, but had them imagine the smiling faces belonged to salesclerks in a shoe store. In some cases the salesclerks had just sold the students a pair of shoes — in which they might well have a genuine smile of satisfaction. In other trials, they imagined that the salesclerks were trying to sell them a pair of shoes — in which case they might be trying to woo the customer with a fake smile...In reality, the scientists use a combination of real and fake smiles for both groups of salesclerks. When the students were free to mimic the smiles, their judgments were not affected by what the salesclerk was doing...But if the students put a pencil in their mouth, they could no longer rely on their mimicry. Instead, they tended to believe that the salesclerks who were trying to sell them shoes were faking their smiles — even when their smiles were genuine. Likewise, they tended to say that the salesclerks who had finished the sale were smiling for real, even when they weren’t. In other words, they were forced to rely on the circumstances of the smile, rather than the smile itself.

Thursday, January 27, 2011

Our Guts 'R Us

It dents my tidy self image just a bit when I read articles like this one from Atarashi et al. (summarized by Barnes and Powrie). A very indispensible part of my 'self' is an astounding 1014 bacteria that reside in the large intestine alone, alongside various viruses, fungi, protozoa, and parasites, all of which can affect chronic disease progression. Lee and Mazmanian point out that:

Although microbes have been classically viewed as pathogens, it is now well established that the majority of host-bacterial interactions are symbiotic. During development and into adulthood, gut bacteria shape the tissues, cells, and molecular profile of our gastrointestinal immune system. This partnership, forged over many millennia of coevolution, is based on a molecular exchange involving bacterial signals that are recognized by host receptors to mediate beneficial outcomes for both microbes and humans....specific aspects of the adaptive immune system are influenced by intestinal commensal bacteria. Understanding the molecular mechanisms that mediate symbiosis between commensal bacteria and humans may redefine how we view the evolution of adaptive immunity and consequently how we approach the treatment of numerous immunologic disorders.
The Lee and  Mazmanian review contains this striking graphic:


Legend: The microbiome of various anatomical locations of the human body. Numerous bacterial species colonize the mouth, upper airways, skin, vagina, and intestinal tract of humans. The phylogenetic trees show the speciation of bacterial clades from common ancestors at each anatomical site. Although the communities in different regions of the body share similarities, they each have a unique site-specific “fingerprint” made of many distinct microbes. Each site has a very high level of diversity, as shown by the individual lines on the dendrograms. Data are from the NIH-funded Human Microbiome Project; circles represent bacterial species whose sequences are known.
The  Atarashi et al. article demonstrates that
...indigenous species of Clostridium bacteria, a large component of our mammalian microbiota, promote anti-inflammatory immune responses by expanding and activating regulatory T cells...Oral inoculation of Clostridium during the early life of conventionally reared mice results in resistance to colitis and systemic immunoglobulin E responses in adult mice, suggesting a new therapeutic approach to autoimmunity and allergy.
These results are of some interest to us humans!

Wednesday, January 26, 2011

Some factoids on exercise and health.

I thought I would list out four interesting chunks from the Wellness Blog at the NY Times:

It's well know that exercise can be an antidote to depression. This is particularly relevant to people living in Northern regions with very short periods of daylight. How much exercise do you need to avoid feeling gloomy? Not much, it turns out. According to a study published in this month’s British Journal of Sports Medicine: a mere 20 minutes a week of any physical activity, whether sports, walking, gardening or even housecleaning, will do it... Exactly how much physical activity is required to obtain its health benefits? A review of dozens of studies on the health effects of exercise did:

ultimately reach some conclusions about how much — or, really, how little — exercise we each should be doing. That minimum amount of exercise required to see a significant lowering of your risk of dying prematurely was, they concluded, 500 MET minutes of exercise a week... A single MET, or Metabolic Equivalent of Task, is the amount of energy a person uses at rest. Two METs represent twice the energy burned at rest; four METs, four times the energy used at rest; and so on. Walking at three miles per hour is a 3.3-MET activity, while running at 6 miles an hour is a 10-MET activity. The committee concluded that a person needs to accumulate a weekly minimum of 500 MET minutes of exercise, which does not mean 500 minutes of exercise. Instead, 150 minutes a week (two and a half hours) of a moderate, three- to five-MET activity, such as walking, works out to be about 500 MET minutes. Half as much time (an hour and 15 minutes per week) spent on a 6-plus MET activity like easy jogging seems, according to the committee, to have similar health effects.

Interestingly, they did not find that exercise beyond a certain point conferred significant additional health benefits. Instead, the “dose response” for exercise, the committee found, is “curvilinear.” In other words, people who are the least active to start with get the most health benefit from starting to exercise. People who already are fit don’t necessarily get a big additional health benefit from adding more workout time to their regimens.
Of particular interest to a worrywart like myself who is extremely physically fit, but concerned about the normal loss of muscle mass that occurs in my age group (65-75) over the next ten years,  a recent study suggests that visiting the gym only once a week is sufficient to hold on to muscle mass and previous strength gains.

It has now been shown that weight resistance training, as well as aerobic exercise, boosts levels of the brain growth factor BNDF and cognitive enhancement (in rats, that is, and most likely us too.)

A further curious counterintuitive note:  Exercising increases the urge to drink alcohol,  and drinkers are more likely to exercise more.

Tuesday, January 25, 2011

Why loneliness is hazardous to your health

Greg Miller does an interesting review article in Science Magazine that describes numerous recent studies on the effect of loneliness on our physiology, health, and longevity. The article focuses on the work of John Cacioppo, a Univ. of Chicago psychologist who is credited with founding the field of social neuroscience. Here is the summary, followed by a few clips and rephrasings from the article:

In a steady stream of recent papers, social psychologists have identified several potentially unhealthy changes in the cardiovascular, immune, and nervous systems of chronically lonely people. The findings could help explain why epidemiological studies have often found that socially isolated people have shorter life spans and increased risk of a host of health problems, including infections, heart disease, and depression. The work also adds a new wrinkle, suggesting that it's the subjective experience of loneliness that's harmful, not the actual number of social contacts a person has. An impressive network of collaborations with researchers in other disciplines is now pioneering a new science of loneliness.

...scores of studies have found that people who lack social support are more prone to a variety of ailments. An analysis of 148 of these studies, published in the July 2010 issue of PLoS Medicine, suggests that social isolation increases the risk of death about as much as smoking cigarettes and more than either physical inactivity or obesity...loneliness is a health risk on its own, apart from conditions such as depression or stress that are common fellow travelers. More specifically, it seems to be the subjective experience of loneliness that's important for people's well-being rather than any objective measure of social connectivity (the number of close contacts someone has, for example).

The UCLA Loneliness Scale is based on a questionnaire that tries to size up how people perceive their social situation, with questions about how often they feel a lack of companionship, feel they have no one to talk to, or feel out of tune with those around them....When people score high on this scale, they also tend to exhibit several physiological changes that effectively put the body in a state of alert... people exhibit higher vascular resistance, a tightening of the arteries that raises blood pressure, forces the heart to work harder, and contributes to wear and tear on vessels...They have elevated molecular markers of stress - cortisol and epinephrine are elevated in saliva and urine, respectively.

Lonely people exhibit increased activity for several genes encoding signaling molecules that promote inflammation and decreased activity for genes that normally put the brakes on inflammation. They also show diminished activity in genes that help mount a defense against viral invaders....This..jibes with epidemiologic findings that socially isolated people are more susceptible to viruses, from the common cold to HIV, and to cardiovascular disease, which has been linked to excess inflammation.

Those who are lonelier, as rated by the UCLA Loneliness Scale, exhibit less activation in the ventral striatum, a component of the brain's reward circuitry, when they view pictures of smiling faces. They also show increased reactivity in the threat-detecting amygdala to pictures of angry or fearful faces.

...loneliness is partly heritable..a recent study, published in the July 2010 issue of Behavioral Genetics, used an abbreviated version of the UCLA Loneliness Scale in a survey sent to 8683 twins and family members. In this group, genetics accounted for 37% of the variability in loneliness, somewhat lower than in some previous studies. Overall, the heritability of loneliness is comparable to that of depression, but less than that of traits such as high blood pressure and cholesterol levels.

The news isn't all bad...Even for hard cases, Cacioppo believes loneliness can be overcome. He and colleagues recently conducted a meta-analysis of 20 studies on interventions for loneliness. Simply providing social support doesn't seem to work, especially if people know they're being looked after...The most effective interventions were those that borrowed methods from cognitive behavioral therapy to shift people's attention and interpretation of social situations in a more positive direction.

Monday, January 24, 2011

The chemistry of enjoying music

Robert Zatorre is an imaginative and productive musician/scientist. His website offers a cornucopia of information on the brain and music. A recent study from his group published in Nature Neuroscience observes how the 'pleasure molecule' dopamine and different brain regions change activity during the anticipation of, and emotional response to, music (many other physiological variables are also measured). His website lets you listen to the musical stimuli used in the studies, some of the most emotional chunks of music ever written. Just listening to a few of them reduced me to a puddle. (Now I know where to go for a quick emotional pleasure boost!). Jonah Lehrer's review of this work is excellent, a much better summary than I would do.  Here is Zatorre's abstract:

Music, an abstract stimulus, can arouse feelings of euphoria and craving, similar to tangible rewards that involve the striatal dopaminergic system. Using the neurochemical specificity of [11C]raclopride positron emission tomography scanning, combined with psychophysiological measures of autonomic nervous system activity, we found endogenous dopamine release in the striatum at peak emotional arousal during music listening. To examine the time course of dopamine release, we used functional magnetic resonance imaging with the same stimuli and listeners, and found a functional dissociation: the caudate was more involved during the anticipation and the nucleus accumbens was more involved during the experience of peak emotional responses to music. These results indicate that intense pleasure in response to music can lead to dopamine release in the striatal system. Notably, the anticipation of an abstract reward can result in dopamine release in an anatomical pathway distinct from that associated with the peak pleasure itself. Our results help to explain why music is of such high value across all human societies.

Friday, January 21, 2011

Age defying or denying? Real life among the old old.

Studies or ideas about human aging are frequently the subjects of posts in this blog (given that I have a vested interest in the aging of yours truly...), and I thought this perspective offered by Susan Jacoby, author of the forthcoming “Never Say Die: The Myth and Marketing of the New Old Age,” as she turns 65, was a very sane one:

..people my age and younger still pretend that old age will yield to what has long been our generational credo — that we can transform ourselves endlessly, even undo reality, if only we live right. “Age-defying” is a modifier that figures prominently in advertisements for everything from vitamins and beauty products to services for the most frail among the “old old,” as demographers classify those over 85. You haven’t experienced cognitive dissonance until you receive a brochure encouraging you to spend thousands of dollars a year for long-term care insurance as you prepare to “defy” old age....“Deny” is the word the hucksters of longevity should be using. Nearly half of the old old — the fastest-growing segment of the over-65 population — will spend some time in a nursing home before they die, as a result of mental or physical disability.

Researchers who were part of a panel discussion titled “90 Is the New 50,” presented at the World Science Festival in 2008, spoke to a middle-aged, standing-room-only audience about imminent medical miracles...The trouble with expecting 90 to become the new 50 is it can stop rational discussion — on a societal as well as individual level — about how to make 90 a better 90. This fantasy is a lot like waiting for Prince Charming, in that it doesn’t distinguish between hope and reasonable expectation.

The risk of dementia, of which Alzheimer’s is the leading cause, doubles every five years after 65...Contrary to what the baby boom generation prefers to believe, there is almost no scientifically reliable evidence that “living right” — whether that means exercising, eating a nutritious diet or continuing to work hard — significantly delays or prevents Alzheimer’s. This was the undeniable and undefiable conclusion in April of a major scientific review sponsored by the National Institutes of Health...Good health habits and strenuous intellectual effort are beneficial in themselves, but they will not protect us from a silent, genetically influenced disaster that might already be unfolding in our brains. I do not have the slightest interest in those new brain scans or spinal fluid tests that can identify early-stage Alzheimer’s. What is the point of knowing that you’re doomed if there is no effective treatment or cure? As for imminent medical miracles, the most realistic hope is that any breakthrough will benefit the children or grandchildren of my generation, not me.
Jacoby on her own situation:
I would rather share the fate of my maternal forebears — old old age with an intact mind in a ravaged body — than the fate of my other grandmother. But the cosmos is indifferent to my preferences, and it is chilling to think about becoming helpless in a society that affords only the most minimal support for those who can no longer care for themselves. So I must plan, as best I can, for the unthinkable.

..I must find someone I trust to make medical decisions for me if I cannot make them myself. This is a difficult emotional task, and it does not surprise me, for all of the public debate about end-of-life care in recent years, that only 30 percent of Americans have living wills. Even fewer have actually appointed a legal representative, known as a health care proxy, to make life-and-death decisions...I can see that the “90 is the new 50” crowd might object to my thinking more about worst-case scenarios than best-case ones. But if the best-case scenario emerges and I become one of those exceptional “ageless” old people so lauded by the media, I won’t have a problem. I can also take it if fate hands me a passionate late-in-life love affair, a financial bonanza or the energy to write more books in the next 25 years than I have in the past 25.

Thursday, January 20, 2011

Distortions of mind perception in psychopathology

A really interesting perspective comes from Daniel Wegner and co-workers in the Psychology Dept. at Harvard. (Wegner's book, "The Illusion of Conscious Will" is in my cannon of must-read books on self and consciousness). From their introduction:

Originally thought to proceed along a single dimension, mind perception has been revealed in a factor-analytic study to occur along independent dimensions of experience (e.g., the capacity for pleasure, fear, hunger) and agency (e.g., the capacity for self-control, planning, memory. Adult humans are typically seen as capable of both experience and agency, whereas children and animals are seen as capable of mainly experience. Gods and robots are seen as capable of mainly agency, and the dead are seen as capable of neither.

We suggest that a number of disorders may be characterized as specific distortions of mind perception, atypical ascriptions of mental capacities to other entities....Successful interaction with the world requires knowing which entities have minds and which do not. Mind perception can therefore be distorted by overperception (perceiving a nonexistent mind) and underperception (failing to perceive an existent mind). Research suggests that both can be associated with adverse consequences for perceivers and targets, consequences that range from social faux pas to violence and death. For example, the overperception of mind in infants can lead to child abuse, but the underperception of mind in adults can lead to the denial of moral rights.
Their abstract:
It has long been known that psychopathology can influence social perception, but a 2D framework of mind perception provides the opportunity for an integrative understanding of some disorders. We examined the covariation of mind perception with three subclinical syndromes—autism-spectrum disorder, schizotypy, and psychopathy—and found that each presents a unique mind-perception profile. Autism-spectrum disorder involves reduced perception of agency in adult humans. Schizotypy involves increased perception of both agency and experience in entities generally thought to lack minds. Psychopathy involves reduced perception of experience in adult humans, children, and animals. Disorders are differentially linked with the over- or underperception of agency and experience in a way that helps explain their real-world consequences.

Smart Phone people...

A bit of humour from the TalkAndroid website (click on image to enlarge and read the captions):

Wednesday, January 19, 2011

Recursive inference of the beliefs of others.

Yoshida et al. (Dolan's group at Wellcome Center, UC, London) do a fascinating imaging study that identifies areas in the pre-frontal cortex that are involved when we attempt to infer what others expect us to do:

Humans have the arguably unique ability to understand the mental representations of others. For success in both competitive and cooperative interactions, however, this ability must be extended to include representations of others' belief about our intentions, their model about our belief about their intentions, and so on. We developed a "stag hunt" game in which human subjects interacted with a computerized agent using different degrees of sophistication (recursive inferences) and applied an ecologically valid computational model of dynamic belief inference. We show that rostral medial prefrontal (paracingulate) cortex, a brain region consistently identified in psychological tasks requiring mentalizing, has a specific role in encoding the uncertainty of inference about the other's strategy. In contrast, dorsolateral prefrontal cortex encodes the depth of recursion of the strategy being used, an index of executive sophistication. These findings reveal putative computational representations within prefrontal cortex regions, supporting the maintenance of cooperation in complex social decision making.

Tuesday, January 18, 2011

Good Dog!

In this morning's NYTimes Science section there is an article about a border collie named Chaser who has been taught 1,022 nouns, names associated with different objects she has been taught to fetch. Chaser was also taught to distinguish verbs, becoming able to paw, nose or take an object requested. It took some effort to exclude the possibility of the "Clever Hans Effect" -  that subtle clues from human handlers might have influenced the dog.

Financial reward undermines intrinsic incentives.

Kurayama et al. measure brain activity during conditions of apparent intrinsic and extrinsic motivation to show striking evidence for a phenomenon often noted in social psychology — namely, extrinsic incentives (pay) can undermine intrinsic incentives (fun).

Contrary to the widespread belief that people are positively motivated by reward incentives, some studies have shown that performance-based extrinsic reward can actually undermine a person's intrinsic motivation to engage in a task. This “undermining effect” has timely practical implications, given the burgeoning of performance-based incentive systems in contemporary society. It also presents a theoretical challenge for economic and reinforcement learning theories, which tend to assume that monetary incentives monotonically increase motivation. Despite the practical and theoretical importance of this provocative phenomenon, however, little is known about its neural basis. Herein we induced the behavioral undermining effect using a newly developed task, and we tracked its neural correlates using functional MRI. Our results show that performance-based monetary reward indeed undermines intrinsic motivation, as assessed by the number of voluntary engagements in the task. We found that activity in the anterior striatum and the prefrontal areas decreased along with this behavioral undermining effect. These findings suggest that the corticobasal ganglia valuation system underlies the undermining effect through the integration of extrinsic reward value and intrinsic task value.

Monday, January 17, 2011

Living for "The Whoosh"

Scanning my long list of links that haven't quite made it into a MindBlog post, I note this Op-Ed piece by David Brooks from Dec. 31, in which he summarizes the main arguments in a new history of Western Philosophy by Dreyfus and Kelly, "All Things Shining."

Dreyfus and Kelly start with Vico’s old idea that each age has its own lens through which people see the world. In the Middle Ages, for example, “people could not help but experience themselves as determined or created by God.” They assumed that God’s plans encompassed their lives the way we assume the laws of physics do...For the past hundred years or so, we have lived in a secular age...individuals have to find or create their own meaning.

Dreyfus and Kelly...are on to something important when they describe the way — far more than in past ages — sports has risen up to fill a spiritual void...Spiritually unmoored, many people nonetheless experience intense elevation during the magical moments that sport often affords. They call this experience “whooshing up.” We get whooshed up at a sports arena, at a political rally or even at magical moments while woodworking or walking through nature...We should not expect these experiences to cohere into a single “meaning of life.” Transcendent experiences are plural and incompatible...Our most vibrant institutions are collective, not individual or religious. They are there to create that group whoosh: the sports stadium, the concert hall, the political rally, the theater, the museum and the gourmet restaurant. Even church is often more about the ecstatic whoosh than the theology...Real life is more about serial whooshes than coherent meaning. (Though they try, Dreyfus and Kelly don’t give us a satisfying basis upon which to distinguish the whooshing some people felt at civil rights rallies from the whooshing others felt at Nazi rallies.)

Examples of the relativity of our sensing time...

Two recent articles give fascinating glimpses of how plastic our sense of time can be. Jiga-Boy et al. show that our perception of temporal distance to a future event is shaped by the effort we must invest to realize the event. In a series of five experiments they showed:

...that the perception of temporal distance to a future event is shaped by the effort one must invest to realize the event...when actors are faced with realizing an event by a certain deadline, more effortful events are perceived as closer in time, regardless of the objective temporal distance to the deadline. This negative relationship is reversed, however, when deadlines are absent. Finally, priming high effort reduced perceived temporal distance to an event, whereas priming low effort increased perceived temporal distance to the event.
Carrozzo et al. find that animacy speeds up time in the brain:
...observers were asked to intercept a moving target or to discriminate the duration of a stationary flash while viewing different scenes. Time estimates were systematically shorter in the sessions involving human characters moving in the scene than in those involving inanimate moving characters. Remarkably, the animate/inanimate context also affected randomly intermingled trials which always depicted the same still character...The existence of distinct time bases for animate and inanimate events might be related to the partial segregation of the neural networks processing these two categories of objects, and could enhance our ability to predict critically timed actions.

Friday, January 14, 2011

Modeling the World in the Brain

Berkes et al. show that spontaneous activity in the visual brain adapts during development to resemble the activity generated by external natural scenes. Here is background from the Science summary:

There is a wide consensus in neuroscience that the brain uses internal models to interpret external stimuli and to make predictions about future events. Despite this consensus and a rich history of studies providing ample behavioral evidence about optimal internal models in the brain, it has been difficult to identify the neural signatures of these internal models. Using statistical methods to analyze recordings from the visual cortex of ferrets, Berkes et al. found that neuronal firing patterns during spontaneous activity were similar to those during evoked activity. During development, it seems that the internal model in the visual cortex gradually adapts to the properties of natural visual scenes.
And the abstract:
The brain maintains internal models of its environment to interpret sensory inputs and to prepare actions. Although behavioral studies have demonstrated that these internal models are optimally adapted to the statistics of the environment, the neural underpinning of this adaptation is unknown. Using a Bayesian model of sensory cortical processing, we related stimulus-evoked and spontaneous neural activities to inferences and prior expectations in an internal model and predicted that they should match if the model is statistically optimal. To test this prediction, we analyzed visual cortical activity of awake ferrets during development. Similarity between spontaneous and evoked activities increased with age and was specific to responses evoked by natural scenes. This demonstrates the progressive adaptation of internal models to the statistics of natural stimuli at the neural level.

Further debate on anti-aging molecule resveratrol

As a drug trial is stopped, the current and former leaders of the pharmaceutical company Sirtris disagree on whether we should be taking resveratrol, the putative anti-aging compound. My previous post on MindBlog's resveratrol experiment and its side effects drew numerous comments and accounts of personal experiences. (By the way, entering 'resveratrol' in the 'Search MindBlog:' box in the column to your left pulls up 18 MindBlog posts referring to resveratrol.)

Thursday, January 13, 2011

The dark side of oxytocin

Nicholas Wade does a further discussion of work I mentioned in my June 22 post on several studies on oxytocin (the 'trust' hormone).

The love and trust it promotes are not toward the world in general, just toward a person’s in-group. Oxytocin turns out to be the hormone of the clan, not of universal brotherhood. Psychologists trying to specify its role have now concluded it is the agent of ethnocentrism.

Difficulty of seeing changes in moving objects.

A nice demonstration by Suchow and Alvarez. Play the movie while looking at the small white speck in the center of the ring. At first, the ring is motionless and it's easy to tell that the dots are changing color. When the ring begins to rotate, the dots suddenly appear to stop changing. But in reality they are changing the entire time. Take a look.

Wednesday, January 12, 2011

How our brains optimize our rewards

In the absence of other options, we use trial-and-error (reinforcement) learning to discover which of our actions are most likely to yield rewards. We can avoid multiple errors, however, if we receive some instruction on our choice selections. Li et al., (open access) observe the brain areas whose activations correlate with these two approaches by designing an experiment with two sessions using a simple probabilistic reward task. In the “feedback” session, participants’ choices were only based on the win/loss feedback, and in the “instructed” session participants could also incorporate the correct cue-reward probability information provided by experimenter to guide choice behavior (see Figure 1 for experimental design). The bottom line is that we use our dorsolateral prefrontal cortex to dynamically adjust outcome responses in valuation regions depending on the usefulness of action-outcome information. Here is their abstract:

Recent research in neuroeconomics has demonstrated that the reinforcement learning model of reward learning captures the patterns of both behavioral performance and neural responses during a range of economic decision-making tasks. However, this powerful theoretical model has its limits. Trial-and-error is only one of the means by which individuals can learn the value associated with different decision options. Humans have also developed efficient, symbolic means of communication for learning without the necessity for committing multiple errors across trials. In the present study, we observed that instructed knowledge of cue-reward probabilities improves behavioral performance and diminishes reinforcement learning-related blood-oxygen level-dependent (BOLD) responses to feedback in the nucleus accumbens, ventromedial prefrontal cortex, and hippocampal complex. The decrease in BOLD responses in these brain regions to reward-feedback signals was functionally correlated with activation of the dorsolateral prefrontal cortex (DLPFC). These results suggest that when learning action values, participants use the DLPFC to dynamically adjust outcome responses in valuation regions depending on the usefulness of action-outcome information.

Yet another ESP controversy.

Great outrage (described in the NYTimes article by Benedict Carey) is accompanying the forthcoming publication by The Journal of Personality and Social Psychology of a paper (link to PDF of paper is in Carey article) by Daryl J. Bem, who describes experiments over 10 years with ~10,000 students testing their ability to accurately sense random events. The critics maintain that extraordinary claims (conflicting with known science) require extraordinary validation (better than the usual 'less than 1/100 chance of being due to random correlation). Several critiques are being published alongside the Bem article, some presumably taking note  of the issues raised in Jonah Lehrer article that I described in a recent post,"The Truth Wears Off."  The last 50 years has seen multiple instances of seemingly (statistically significant) results on ESP,  drug effects, psychological mechanisms,  disappear over time as the experiments are repeated. (added note: in yesterday's NY Times Carey gives an excellent discussion of the statistics involved, in very simple language.)

Tuesday, January 11, 2011

Our digital afterlives - Deric's version

The NYTimes Sunday magazine has an interesting article by Rob Walker, raising issues that had been in my penumbra of awareness but that I've now felt forced to address directly. What happens to all the stuff you have put on the internet (photos, blogs, etc.) when you die? You should read the article.

I'll give you my own version of the issues it raises: Like many of us, I entered the web world via an early micro-computer (Apple II in my case, which appeared before the early IBM PC) with a slow phone modem. I got into chat rooms on AOL (using a pseudonym, then used that pseudonym for my first website on geocities.com, which was purchased by Yahoo, and the no-longer-relevant pseudonym was the account name used when I purchased the dericbownds.net domain name that now contain mindblog.dericbownds.net, which is simply a pointer used by google.com (i.e., blogspot.com), which actually hosts MindBlog. The images for the blog are stored, however, not by google, but on my own yahoo-hosted website at dericbownds.net/uploaded_images. Beyond this, I have data on several photo sites, five email addresses, logins and memberships and data on 10-20 social web sites, 61 piano performances on YouTube (with more to come), contact and calendar data on google...... What a mess!

So, what happens when I get run over by a truck tomorrow? I've recently (securely..not by email) passed on to my son and daughter a document titled Hit_By_Bus that hopefully contains enough information for them to sort through this mess and delete most of the material out there (hopefully condensing to a posthumus residue that covers family, university career, dericbownds.net, mindblog, and the piano performances). I don't envy their job, but I'm too lazy to do it myself.

So..what have you done? (Only about a third of Americans even have a will.)

Gay or Straight - same brain regions activated by love partner.

Here is an interesting bit from Semir Zeki, a well know vision scientist who has also studies brain correlates of artistic appreciation and brain systems and networks that are critical for the sentiment of romantic love. The article contains useful references. The abstract:

We pursued our functional magnetic resonance imaging (fMRI) studies of the neural correlates of romantic love in 24 subjects, half of whom were female (6 heterosexual and 6 homosexual) and half male (6 heterosexual and 6 homosexual). We compared the pattern of activity produced in their brains when they viewed the faces of their loved partners with that produced when they viewed the faces of friends of the same sex to whom they were romantically indifferent. The pattern of activation and de-activation was very similar in the brains of males and females, and heterosexuals and homosexuals. We could therefore detect no difference in activation patterns between these groups.

Monday, January 10, 2011

"Not tonight, dear" chemical signal in women's tears.

Anytime I see an article on article on evidence for a new human pheromone (a chemical signal that we secrete and sense - from arm pits, sweat, crotch, whatever) I pass it it on. Below is the abstract from  Gelstein et al, and here is a brief account from the NYTimes.

Emotional tearing is a poorly understood behavior that is considered uniquely human. In mice, tears serve as a chemosignal. We therefore hypothesized that human tears may similarly serve a chemosignaling function. We found that merely sniffing negative-emotion–related odorless tears obtained from women donors, induced reductions in sexual appeal attributed by men to pictures of women’s faces. Moreover, after sniffing such tears, men experienced reduced self-rated sexual arousal, reduced physiological measures of arousal, and reduced levels of testosterone. Finally, functional magnetic resonance imaging revealed that sniffing women's tears selectively reduced activity in brain-substrates of sexual arousal in men.

Friday, January 07, 2011

People believe they have more free will than others

Interesting observations from Pronin and Kuglera:

Four experiments identify a tendency for people to believe that their own lives are more guided by the tenets of free will than are the lives of their peers. These tenets involve the a priori unpredictability of personal action, the presence of multiple possible paths in a person's future, and the causal power of one's personal desires and intentions in guiding one's actions. In experiment 1, participants viewed their own pasts and futures as less predictable a priori than those of their peers. In experiments 2 and 3, participants thought there were more possible paths (whether good or bad) in their own futures than their peers’ futures. In experiment 4, participants viewed their own future behavior, compared with that of their peers, as uniquely driven by intentions and desires (rather than personality, random features of the situation, or history)

...Philosophers have long speculated that the introspective feeling of free will provides the force behind people's belief in it. By placing heavy weight on our own introspections (but not those of others), we may find ourselves uniquely convinced of our own free will. In some ways, this conviction is likely to be liberating—endowing us with a greater feeling of power in our lives.

Thursday, January 06, 2011

Is the face alive? - the eyes tell us.

Looser and Wheatley do a nice study, reported in Psychological Science, on how we determine whether a face is dead or alive. A review of the work in Science Now has some nice videos of morphing faces along a gradient of animacy. The authors paired doll faces with a similar-looking human faces and used morphing software to blend the two, ending up with a spectrum of pictures that ranged from fully human to part human-part doll to purely doll. Volunteers consistently looked mainly at the eyes, and selected as the dividing point those faces that were about two-thirds along the continuum, closer to the human end. They also attributed the capability of thought to those faces.

Wednesday, January 05, 2011

The social sense - Theory of mind in 7-month old human infants.

A core component of our social cognition is the capacity to formulate a representation of what someone else believes to be true, even if that belief is false, and it has generally been accepted that this ability (theory of mind, or ToM) does not appear until children are 3-4 years old. Kovács et al. have found a behavioral paradigm, that when applied to both adults and infants, suggests that they form representations of others' beliefs in the same way. They developed a method for investigating ToM mechanisms that, in contrast to variants of the standard false belief task, is implicit, makes no reference to others’ beliefs, and requires no behavioral predictions of what agents will do on the basis of their beliefs. They used an object detection task to investigate two questions. First, are belief computations automatically triggered by the mere presence of an agent in adults and in infants as young as 7 months, even when the beliefs are entirely irrelevant to the task participants have to perform? Second, are beliefs about others’ beliefs stored in a format sufficiently similar to our own representations about the environment that both types of representations can affect our behavior?

Human social interactions crucially depend on the ability to represent other agents’ beliefs even when these contradict our own beliefs, leading to the potentially complex problem of simultaneously holding two conflicting representations in mind. Here, we show that adults and 7-month-olds automatically encode others’ beliefs, and that, surprisingly, others’ beliefs have similar effects as the participants’ own beliefs. In a visual object detection task, participants’ beliefs and the beliefs of an agent (whose beliefs were irrelevant to performing the task) both modulated adults’ reaction times and infants’ looking times. Moreover, the agent’s beliefs influenced participants’ behavior even after the agent had left the scene, suggesting that participants computed the agent’s beliefs online and sustained them, possibly for future predictions about the agent’s behavior. Hence, the mere presence of an agent automatically triggers powerful processes of belief computation that may be part of a “social sense” crucial to human societies.

Tuesday, January 04, 2011

Brain correlates of choice-induced preference change.

In an interesting article, Izuma et al. call classical cognitive dissonance theory into question. Their observations suggest that our preference for our choice between two equally desirable items is established by the act of choosing, not by a subsequent reduction of our preference for one of them. In other words, the mere act of rejecting favorite goods actually reduces preferences for them. Their abstract gives a clear summary of their observations:

According to many modern economic theories, actions simply reflect an individual's preferences, whereas a psychological phenomenon called “cognitive dissonance” claims that actions can also create preference. Cognitive dissonance theory states that after making a difficult choice between two equally preferred items, the act of rejecting a favorite item induces an uncomfortable feeling (cognitive dissonance), which in turn motivates individuals to change their preferences to match their prior decision (i.e., reducing preference for rejected items). Recently, however, Chen and Risen [Chen K, Risen J (2010) J Pers Soc Psychol 99:573–594] pointed out a serious methodological problem, which casts a doubt on the very existence of this choice-induced preference change as studied over the past 50 y. Here, using a proper control condition and two measures of preferences (self-report and brain activity), we found that the mere act of making a choice can change self-report preference as well as its neural representation (i.e., striatum activity), thus providing strong evidence for choice-induced preference change. Furthermore, our data indicate that the anterior cingulate cortex and dorsolateral prefrontal cortex tracked the degree of cognitive dissonance on a trial-by-trial basis. Our findings provide important insights into the neural basis of how actions can alter an individual's preferences.

Monday, January 03, 2011

Influence of language on perception

Landau et al. show that hearing recorded sentences describing faces (versus places) enhances a subsequent electrophysiological marker of brain responses to pictures of faces, while seeing pictures of faces diminishes the subsequent responses. This shows that language influences early stages of visual processing.

We examined the effect of linguistic comprehension on early perceptual encoding in a series of electrophysiological and behavioral studies on humans. Using the fact that pictures of faces elicit a robust and reliable evoked response that peaks at ~170 ms after stimulus onset (N170), we measured the N170 to faces that were preceded by primes that referred to either faces or scenes. When the primes were auditory sentences, the magnitude of the N170 was larger when the face stimuli were preceded by sentences describing faces compared to sentences describing scenes. In contrast, when the primes were visual, the N170 was smaller after visual primes of faces compared to visual primes of scenes. Similar opposing effects of linguistic and visual primes were also observed in a reaction time experiment in which participants judged the gender of faces. These results provide novel evidence of the influence of language on early perceptual processes and suggest a surprising mechanistic description of this interaction: linguistic primes produce content-specific interference on subsequent visual processing. This interference may be a consequence of the natural statistics of language and vision given that linguistic content is generally uncorrelated with the contents of perception.