MindBlog's winter office...

Inspired by 'the view from your window' feature of Andrew Sullivan's Blog, I thought I would post an iPhone photo of where I am sitting (in Fort Lauderdale, Florida) as I bang out MindBlog's posts. I will be heading back to Madison Wisconsin in early April.

How to keep from stumbling on steps...

Elliott et al. make the neat observation that a simple visual illusion can lead to safer stepping behavior. The perceived height of a step is manipulated as shown in this figure:

Subjects perceived the step to be higher in the V (vertical stripes on the height dimension) configuration on the right compared to the H (horizontal stripes) configuration on the left, and correspondingly raised their toes higher to clear the step.

Neuroscience and the soul.

A recent letter from Martha Farah to Science Magazine is worth passing on:

Science and religion have had a long relationship, by turns collegial and adversarial. In the 17th century Galileo ran afoul of the Church's geocentrism, and in the 19th century Darwin challenged the biblical account of creation. The breaches that open at such times often close again, as religions determine that the doctrine in question is not an essential part of faith. This is precisely what happened with geocentrism and, outside of certain American fundamentalist Christian sects, evolution.

A new challenge to the science-religion relationship is currently at hand. We hope that, with careful consideration by scientists and theologians, it will not become the latest front in what some have called the "culture war" between science and religion. The challenge comes from neuroscience and concerns our understanding of human nature.

Most religions endorse the idea of a soul (or spirit) that is distinct from the physical body. Yet as neuroscience advances, it increasingly seems that all aspects of a person can be explained by the functioning of a material system. This first became clear in the realms of motor control and perception. Yet, models of perceptual and motor capacities such as color vision and gait do not directly threaten the idea of the soul. You can still believe in what Gilbert Ryle called "the ghost in the machine" and simply conclude that color vision and gait are features of the machine rather than the ghost.

However, as neuroscience begins to reveal the mechanisms underlying personality, love, morality, and spirituality, the idea of a ghost in the machine becomes strained. Brain imaging indicates that all of these traits have physical correlates in brain function. Furthermore, pharmacologic influences on these traits, as well as the effects of localized stimulation or damage, demonstrate that the brain processes in question are not mere correlates but are the physical bases of these central aspects of our personhood. If these aspects of the person are all features of the machine, why have a ghost at all?

By raising questions like this, it seems likely that neuroscience will pose a far more fundamental challenge than evolutionary biology to many religions. Predictably, then, some theologians and even neuroscientists are resisting the implications of modern cognitive and affective neuroscience. "Nonmaterialist neuroscience" has joined "intelligent design" as an alternative interpretation of scientific data. This work is counterproductive, however, in that it ignores what most scholars of the Hebrew and Christian scriptures now understand about biblical views of human nature. These views were physicalist, and body-soul dualism entered Christian thought around a century after Jesus' day.

To be sure, dualism is intuitively compelling. Yet science often requires us to reject otherwise plausible beliefs in the face of evidence to the contrary. A full understanding of why Earth orbits the Sun (as a consequence of the way the solar system was formed) took another century after Galileo's time to develop. It may take even longer to understand why certain material systems give rise to consciousness. In the meantime, just as Galileo's view of Earth in the heavens did not render our world any less precious or beautiful, neither does the physicalism of neuroscience detract from the value or meaning of human life.

Saving the world...

A University of Vermont course in the spring of 2008 came up with a magnum opus now published in the Proceedings of the National Academy titled "Overcoming systemic roadblocks to sustainability: The evolutionary redesign of worldviews, institutions, and technologies." I totally have a mind-numbing headache from reading this ponderous but worthwhile effort, and give you a few clips from their summary of "an integrated set of worldviews, institutions, and technologies to stimulate and seed evolutionary redesign of the current socio-ecological regime to achieve global sustainability":

Redefine Well-Being Metrics.
In any new context, we first have to remember that the goal of an economy is to sustainably improve human well-being and quality of life. Material consumption and GDP are merely means to that end, not ends in themselves. We have to recognize, as both ancient wisdom and new psychological research tell us, that material consumption beyond real need can actually reduce overall well-being.
Ensure the Well-Being of Populations During the Transition.
We must ensure that reductions in economic output and consumption fall on those with the lowest marginal utility of consumption, the wealthy. Presently, the U.S. tax code taxes the third wealthiest man in the world, Warren Buffett, at 17.7%, while his receptionist is taxed at the average rate of 30%....although qualitative development may continue indefinitely... existing levels of physical economic output and consumption are already unsustainable and should be reduced.
Reduce Complexity and Increase Resilience.
Efforts to create new cultural/institutional variants can benefit from the lessons offered by history, particularly cases of successful adaptation...Although environmental factors contribute to decline, equally important are the decisions made during the crises. A society's responses depend on the ability of its political, economic, and social institutions to respond, as well as on its cultural values.
Expand the “Commons Sector.”
Recognizing that we are in a biophysical crisis because of our over-consumption and lack of protection of ecosystem services, we must invest in institutions and the technologies required to reduce the impact of the market economy and to preserve and protect public goods. It is now time to create another major category of institution, the commons sector, which would be responsible for managing existing common assets and for creating new ones. Some assets should be held in common because it is more just; these include resources created by nature or by society as a whole.
Remove Barriers to Improving Knowledge and Technology.
With the invention of television, political advertisements became a critical outlet for candidates to broadcast their message and to sway voters. However, the decentralized nature of the Internet allows citizens to gain knowledge about what is done in their name, just as politicians can find out more about those they claim to represent. As a means of two-way communication, the Internet provides voters the ability to speak out within their government without leaving their homes. For the Internet to transform the idea of electronic democracy, universal access is critical. Currently technological, financial, and social barriers exist to such universal accessibility. Removal of these barriers thus becomes a major goal for replacement of the current plutocracy with real democracy.

Persistent effect of early abuse or deprivation on immune function in humans.

The wisconsin group that has studied various aspect of early abuse and deprivation in children offers evidence that adult immune function is compromised in these children, even if they were adopted into nuturing families and more benevolent settings.

It is well known that children need solicitous parenting and a nurturing rearing environment to ensure their normal behavioral development. Early adversity often negatively impacts emotional and mental well-being, but it is less clearly established how much the maturation and regulation of physiological systems is also compromised. The following research investigated the effect of 2 different types of adverse childhood experiences, early deprivation through institutionalization and physical abuse, on a previously unexplored outcome: the containment of herpes simplex virus (HSV). The presence of HSV-specific antibody in salivary specimens was determined in 155 adolescents, including 41 postinstitutionalized, 34 physically-abused, and 80 demographically-similar control youth. Across 4 school and home days, HSV antibody was higher in both postinstitutionalized and physically-abused adolescents when compared with control participants. Because the prevalence of HSV infection was similar across the groups, the elevated antibody was likely indicative of viral recrudescence from latency. Total secretory Ig-A secretion was associated with HSV, but did not account for the group differences in HSV-specific antibody. These findings are likely caused by a failure of cellular immune processes to limit viral reactivation, indicating a persistent effect of early rearing on immune functioning. The fact that antibody profiles were still altered years after adoption into a more benevolent setting with supportive families suggests these results were not caused by contemporaneous factors, but rather reflect a lingering influence of earlier life experiences.

From oral to moral

An interesting synthesis from Chapman et al.

In common parlance, moral transgressions "leave a bad taste in the mouth." This metaphor implies a link between moral disgust and more primitive forms of disgust related to toxicity and disease, yet convincing evidence for this relationship is still lacking. We tested directly the primitive oral origins of moral disgust by searching for similarity in the facial motor activity evoked by gustatory distaste (elicited by unpleasant tastes), basic disgust (elicited by photographs of contaminants), and moral disgust (elicited by unfair treatment in an economic game). We found that all three states evoked activation of the levator labii muscle region of the face, characteristic of an oralnasal rejection response. These results suggest that immorality elicits the same disgust as disease vectors and bad tastes.

A summary graphic from the review of this work by Rozin et al. and some of their comments:

Domains of disgust. The schematic represents routes by which eliciting situations may trigger the disgust output program. Those that run through the disgust evaluation system--which includes appraisal of the elicitor, feelings, and contamination ideation--trigger the full disgust emotion. Solid lines represent routes through which an elicitor can activate the disgust evaluation-output program. Dashed lines (green) represent direct elicitation of the disgust output program. The dotted line (brown) represents a metaphoric, indirect route.

According to the principle of preadaptation, a system that evolves for one purpose is later used for another purpose. From this viewpoint, disgust originates in the mammalian bitter taste rejection system, which directly activates a disgust output system. This primal route (e.g., bitter and some other tastes) evokes only the output program, without a disgust evaluation phase. During human evolution, the disgust output system was harnessed to a disgust evaluation system that responded not to simple sensory inputs (such as bitter tastes) but to more cognitively elaborated appraisals (e.g., a cockroach). Initially, the evaluation system was a food rejection system that rejected potential foods on the basis of their nature or perceived origin. This was the first "true disgust," because it engaged this evaluation system. Later, through some combination of biological and cultural evolution, the eliciting category was enlarged to include reminders of our animal nature, as wel as some people or social groups. This process had adaptive value, because by making things or thoughts disgusting a culture could communicate their negativity and cause withdrawal from them.

Brain activity started by music you think you are going to hear.

Here is an interesting piece of work from Leaver et al:

Music consists of sound sequences that require integration over time. As we become familiar with music, associations between notes, melodies, and entire symphonic movements become stronger and more complex. These associations can become so tight that, for example, hearing the end of one album track can elicit a robust image of the upcoming track while anticipating it in total silence. Here, we study this predictive "anticipatory imagery" at various stages throughout learning and investigate activity changes in corresponding neural structures using functional magnetic resonance imaging. Anticipatory imagery (in silence) for highly familiar naturalistic music was accompanied by pronounced activity in rostral prefrontal cortex (PFC) and premotor areas. Examining changes in the neural bases of anticipatory imagery during two stages of learning conditional associations between simple melodies, however, demonstrates the importance of fronto-striatal connections, consistent with a role of the basal ganglia in "training" frontal cortex. Another striking change in neural resources during learning was a shift between caudal PFC earlier to rostral PFC later in learning. Our findings regarding musical anticipation and sound sequence learning are highly compatible with studies of motor sequence learning, suggesting common predictive mechanisms in both domains.

A mother's experience can alter her offspring's memory performance.

Here are some fascinating experiments, done in mice to be sure (but likely to be shown for humans soon, as with so many other mouse models). It is known that exposure to an enriched environment enhances learning and memory in mice [which is reflected by an enhancement of nerve-nerve signaling in the hippocampus termed long term potentiation (LTP)]. This new study shows that these effects can be transmitted to the next generation; the authors observed that LTP was enhanced in the offspring of enriched mothers. Moreover, the characteristic defects in LTP and contextual fear conditioning of ras–Gfr-knockout mice were masked in the offspring of knockout mice exposed to an enriched environment. These data raise the intriguing possibility that a mother's experience can induce epigenetic changes that influence her offspring's memory performance (see Tuesday's post for information on another maternal effect and information on epigenetic effects). If a similar phenomenon occurs in humans, the effectiveness of one's memory during adolescence, particularly in those with defective cell signaling mechanisms that control memory, can be influenced by environmental stimulation experienced by one's mother during her youth. A portion of the abstract:

The idea that qualities acquired from experience can be transmitted to future offspring has long been considered incompatible with current understanding of genetics. However, the recent documentation of non-Mendelian transgenerational inheritance makes such a "Lamarckian"-like phenomenon more plausible. Here, we demonstrate that exposure of 15-d-old mice to 2 weeks of an enriched environment (EE), that includes exposure to novel objects, elevated social interactions and voluntary exercise, enhances long-term potentiation (LTP) not only in these enriched mice but also in their future offspring through early adolescence, even if the offspring never experience EE. In both generations, LTP induction is augmented by a newly appearing cAMP/p38 MAP kinase-dependent signaling cascade. Strikingly, defective LTP and contextual fear conditioning memory normally associated with ras-grf knock-out mice are both masked in the offspring of enriched mutant parents. The transgenerational transmission of this effect occurs from the enriched mother to her offspring during embryogenesis.

Why pay university tuition?

...when you can get an array of astounding courses from places like Academic Earth, with the videos of the lectures shown in your web browser. I recommend the introductory Psychology course offered by Paul Bloom at Yale.

Our genes influence our social networks

Jackson reviews an analysis by Fowler et al. that suggests that genetic traits influence the social behavior of individuals:

...Fowler et al examined the social network characteristics of 1,110 twins from an Adolescent Health Dataset which is based on interviews of high school students. Presuming that the social environment that twins share is not influenced by whether they are monozygotic or dizygotic, if network characteristics are significantly more correlated among monozygotic twins than dizygotic twins then there is evidence for a genetic role in network formation.

The network characteristics that Fowler et al.investigate are: in-degree (how many students name a given student as a friend), out-degree (how many students a given student names as friends), transitivity (if A and B are friends, and B and C are friends, what is the likelihood that A and C are friends), and betweenness centrality (the fraction of shortest paths between other pairs of students that a given student lies on). Their statistical analysis assumes that the variation in a network characteristic can be additively separated into a component that is genetic, a component caused by the environment that would be shared with a twin, and a component caused by the environment that would not be shared with a twin. The covariance between monozygotic twins is then the variance caused by the common environment plus the variance caused by genetic factors, whereas the covariance between dizygotic twins is the variance caused by the common environment plus half of the variance caused by genetic factors. This formulation allows one to solve for the percentage of variation in a given network characteristic that is caused by each of the genetic, common environment, and unshared environment components. The figure shows that almost half of the variation in transitivity and in-degree are genetically attributable, and more than a quarter of betweenness centrality is genetically attributable, but the genetic component of the out-degree variation is too small to be statistically significant. The common environment is statistically insignificant in all cases. (click on figure to enlarge it).

Fowler et al. tried a number of network models to fit with the data and found the only one which generated a relationship between genetics and transitivity was an “Attract and Introduce” model built on two assumptions. First, some individuals are inherently more attractive than others, whether physically or otherwise, so they receive more friendship nominations. Second, some individuals are inherently more inclined to introduce new friends to existing friends (and hence such individuals will indirectly enhance their own transitivity).

Brain correlates of musical improvisation.

Berkowitz and Ansari report an fMRI study of the brains of trained pianists while they are improvising. To get control conditions for comparisons they designed a series of four activities. In the two general types of tasks, they had subjects either improvise melodies or play pre-learned patterns. Comparing brain activity in these two situations allowed them to focus on melodic improvisation. Subjects did each of these two general tasks either with or without a metronome. When there was no metronome marking time, subjects improvised their own rhythms. Comparing conditions with and without metronome allowed them to look at rhythmic improvisation. A key point is that when the subjects played patterns (instead of improvised melodies), they could choose to play them in any order. Thus there was still some spontaneity in decision making, but the choices were more limited than during improvisation.

The authors observed an overlap between melodic improvisation and rhythmic improvisation in three areas of the brain: the dorsal premotor cortex (dPMC), the anterior cingulate (ACC), and the inferior frontal gyrus/ventral premotor cortex (IFG/vPMC). From a summary of the work by Bannatyne:

“The dPMC takes information about where the body is in space, makes a motor plan, and sends it to the motor cortex to execute the plan. The fact [that] it’s involved in improvisation is not surprising, since it is a motor activity. The ACC is a part of the brain that appears to be involved in conflict monitoring — when you’re trying to sort out two conflicting possibilities, like when you to read the word BLUE when it’s printed in the color red. It’s involved with decision making, which also makes sense — improvisation is decision making, deciding what to play and how to play it.” The IFG/vPMC is perhaps one of the most interesting findings of their study. “This area is known to be involved when people speak and understand language. It’s also active when people hear and understand music. What we’ve shown is that it’s involved when people create music.”

Improvising, from a neurobiological perspective, involves generating, selecting, and executing musical-motor sequences, something that wouldn’t surprise musicians. But in terms of brain research, it’s a new piece of information.

Erasing fear responses and preventing the return of fear.

Kindt et al. demonstrate an interesting effect of a beta-blocker that one thinks might become part of clinical practice soon. They found that a conditioned fear response can be weakened by disrupting the reconsolidation of the fear memory with propranolol and that this disruption prevents the return of fear. While Propranolol disrupts the reconsolidation of the fear memory, it does not disrupt declarative memory (recall of the facts of the fear inducing event). The abstract:

Animal studies have shown that fear memories can change when recalled, a process referred to as reconsolidation. We found that oral administration of the -adrenergic receptor antagonist propranolol before memory reactivation in humans erased the behavioral expression of the fear memory 24 h later and prevented the return of fear. Disrupting the reconsolidation of fear memory opens up new avenues for providing a long-term cure for patients with emotional disorders.

Some details:

The conditioned fear response was measured as potentiation of the eyeblink startle reflex to a loud noise (40 ms, 104 dB) by electromyography of the right orbicularis oculi muscle. Stronger startle responses to the loud noise during the fear-conditioned stimulus (CS1⁺) as compared with the control stimulus (CS2^-) reflects the fearful state of the participant elicited by CS1⁺. Startle potentiation taps directly into the amygdala, and fear-conditioning procedures yield highly reliable and robust startle potentiation.


Figure. (click to enlarge) (a–f) Mean startle potentiation to the fear-conditioned stimulus (CS1), the control stimulus (CS2) and noise alone (NA) trials (left) and mean expectancy scores of the unconditioned stimulus to CS1 and CS2 trials (right) during acquisition (trial 1–8), extinction (trial 1–10) and test (trial 1–5) for the placebo (n = 20, a,b), propranolol reactivation (n = 20, c,d) and propranolol without reactivation (n = 20, e,f) group. CS1⁺ refers to the fear conditioned stimulus during acquisition, CS1^- refers to the fear conditioned stimulus during extinction and test, CS1-R refers to the reactivation of the fear conditioned stimulus and CS2^- refers to the control stimulus during all phases of the experiment. Error bars represent s.e.m.

Transcendence from Neuroscience

Clip from a brief essay by Garreau:

....the new vision of transcendence coming out of neuroscience. It’s long been observed that intelligent organisms require love to develop or even just to survive. Not coincidentally, we can readily identify brain functions that allow and require us to be deeply relational with others. There are also aspects of the brain that can be shown to equip us to experience elevated moments when we transcend boundaries of self. What happens as the implications of all this research starts suggesting that particular religions are just cultural artifacts built on top of universal human physical traits?

Genetic determinants of financial risk taking

Here is an interesting bit from Kuhnen and Chiao, although I'm surprised that the reviewers let them get away with using the word 'determinants' rather than 'correlates':

Individuals vary in their willingness to take financial risks. Here we show that variants of two genes that regulate dopamine and serotonin neurotransmission and have been previously linked to emotional behavior, anxiety and addiction (5-HTTLPR and DRD4) are significant determinants of risk taking in investment decisions. We find that the 5-HTTLPR s/s allele carriers take 28% less risk than those carrying the s/l or l/l alleles of the gene. DRD4 7-repeat allele carriers take 25% more risk than individuals without the 7-repeat allele. These findings contribute to the emerging literature on the genetic determinants of economic behavior.

The gourmet palete - an exercise in hedonistic psychology

John Bohannon does a humorous piece in the Feb. 20 issue of Science:

What did you do on New Year's Eve? I watched my friends eat dog food. Throughout the last night of 2008, I stood in a makeshift laboratory in the corner of a packed Brooklyn house party. I presented people with bowls of paté--labeled A through E--and a pile of crackers. I explained that four of the bowls contained human food, including expensive luxury patés. One was canned dog food that had been pulsed in a food processor, giving it the same consistency as that of paté. My open-minded friends looked thoughtfully into the middle distance as they munched on mouthfuls of each, jotted down their assessment on data sheets, and then drifted back into the party. As the data rolled in, my eyes grew wide with amazement. Nobody was guessing correctly which was the dog food.

...The five samples covered a wide price range: two expensive liver patés (duck and chicken), two cheap imitation patés (puréed liverwurst and Spam), and the ultimate bargain (dog food). My subjects were hopeless at guessing which paté was dog food. But the answer was literally on the tip of their tongues. Although only one in six people correctly guessed that dish C contained the dog food, almost 75% rated it last in terms of taste. People significantly loathed the dog food (Newell and MacFarlane multiple comparison, p less than 0.1), and that did not correlate with relative sobriety. To cap it off, the average taste rankings of the five spreads exactly matched their relative prices.

Perhaps this result is not surprising, given that numerous blind taste tests involving hundreds of people have shown no correlation between the price of wines costing from $1.50 to $150 and their reported taste.

Thought for the day - the Twitter Bubble

I am incredulous that so many people seem to want to share the ongoing details of their life via twitter and facebook. Do I really care to know that friend X is about to brush his teeth and go to bed? Allesandra Stanley writes a humorous piece on this phenomenon. Some clips:

Left alone in a cage with a mountain of cocaine, a lab rat will gorge itself to death. Caught up in a housing bubble, bankers will keep selling mortgage-backed securities — and amassing bonuses — until credit markets seize, companies collapse, and millions of investors lose their jobs and homes....And news anchors and television personalities who have their own shows, Web sites, blogs and pages on Facebook.com and MySpace.com will send Twitter messages until the last follower falls into a coma.

At the height of the subprime folly, there was not enough outside regulation or inner compunction to restrain heedless excess. It’s too late for traders, but that economic mess should be a lesson for those who traffic in information. Like bankers who never feel they’ve earned enough, television anchors and correspondents apparently never feel that they have communicated enough....It’s not just television, of course. Ordinary people, bloggers and even columnists and book authors, who all already have platforms for their views, feel compelled to share their split-second aperçus, no matter how mundane.

Those who say Twitter is a harmless pastime, which skeptics are free to ignore, are ignoring the corrosive secondary effects. We already live in an era of me-first journalism, autobiographical blogs and first-person reportage. Even daytime cable news is clotted with Lou Dobbsian anchors who ooze self-regard and intemperate opinion...On-air meltdowns are the new scoops. The CNBC correspondent Rick Santelli, a former trader, delivered a rant last week on the floor of the Chicago Mercantile Exchange about the Obama administration’s mortgage bailout proposal.

Mr. Santelli, it should be noted, has not lost all restraint: he does not yet have his own Twitter account. Fans created one for him, in case he changes his mind. “Just to let everyone know,” one follower explained. “This is NOT Rick’s account, but it is a place holder for him as soon as WE can convince him to join Twitter. :)”

And that space has, as of 4:20 on Friday afternoon, 158 followers. Twitterers who maintain that their messages must have meaning since they have an audience should keep Mr. Santelli’s void in mind. There are always some people who, given the chance, will respond to anything, even nothing.

How early abuse in humans changes the adult brain.

Studies on rat models have shown that affectionate mothering alters gene expression to dampen physiological responses to stress, while early abuse has the opposite effect. Now these basic results have been extended to humans by McGowan et al., who carried out a study of people who have committed suicide. They found that that people who were abused or neglected as children showed genetic alterations that likely made them more biologically sensitive to stress. An epigenetic regulation of the glucocorticoid receptor gene, NR3C1, is observed in humans who had been abused as children that is consistent with predictions derived from a rodent model in which early postnatal experience influences adult responses to stress. (Decreases in the expression of this receptor increase reactivity to stress.) I pass on their abstract, and here is a nice explanation of what epigenetic changes are (see also the review by Benedict Carey).

Maternal care influences hypothalamic-pituitary-adrenal (HPA) function in the rat through epigenetic programming of glucocorticoid receptor expression. In humans, childhood abuse alters HPA stress responses and increases the risk of suicide. We examined epigenetic differences in a neuron-specific glucocorticoid receptor (NR3C1) promoter between postmortem hippocampus obtained from suicide victims with a history of childhood abuse and those from either suicide victims with no childhood abuse or controls. We found decreased levels of glucocorticoid receptor mRNA, as well as mRNA transcripts bearing the glucocorticoid receptor 1_F splice variant and increased cytosine methylation of an NR3C1 promoter. Patch-methylated NR3C1 promoter constructs that mimicked the methylation state in samples from abused suicide victims showed decreased NGFI-A transcription factor binding and NGFI-A–inducible gene transcription. These findings translate previous results from rat to humans and suggest a common effect of parental care on the epigenetic regulation of hippocampal glucocorticoid receptor expression.

For a tranquil start to your week, Debussy with flowers

I got an email from the fellow who made this video asking if he could use my YouTube videorecording of the Debussy Reverie. I said 'sure, go ahead'.... I'm not too keen on the electronic 'enhancements' he added to my basic piano track to make the first half of the video, but here it is...

Biased minds make better inferences.

Here is an interesting open access article "Homo Heuristicus: Why Biased Minds Make Better Inferences" from the first issue of a new journal from Wiley Interscience, Topics in Cognitive Science. (Check out this free online first issue, there are a number of other fascinating articles). It makes the point that a biased mind can handle uncertainty more efficiently and robustly than an unbiased mind relying on more resource-intensive and general-purpose processing strategies. Its abstract:

Heuristics are efficient cognitive processes that ignore information. In contrast to the widely held view that less processing reduces accuracy, the study of heuristics shows that less information, computation, and time can in fact improve accuracy. We review the major progress made so far: (a) the discovery of less-is-more effects; (b) the study of the ecological rationality of heuristics, which examines in which environments a given strategy succeeds or fails, and why; (c) an advancement from vague labels to computational models of heuristics; (d) the development of a systematic theory of heuristics that identifies their building blocks and the evolved capacities they exploit, and views the cognitive system as relying on an "adaptive toolbox;" and (e) the development of an empirical methodology that accounts for individual differences, conducts competitive tests, and has provided evidence for people's adaptive use of heuristics. Homo heuristicus has a biased mind and ignores part of the available information, yet a biased mind can handle uncertainty more efficiently and robustly than an unbiased mind relying on more resource-intensive and general-purpose processing strategies.

A common brain substrate for evaluating physical and social space.

From Yamakawa et al, work that is consonant with models of embodied cognition (cf. George Lakoff and Mark Johnson) :

Across cultures, social relationships are often thought of, described, and acted out in terms of physical space (e.g. “close friends” “high lord”). Does this cognitive mapping of social concepts arise from shared brain resources for processing social and physical relationships? Using fMRI, we found that the tasks of evaluating social compatibility and of evaluating physical distances engage a common brain substrate in the parietal cortex. The present study shows the possibility of an analytic brain mechanism to process and represent complex networks of social relationships. Given parietal cortex's known role in constructing egocentric maps of physical space, our present findings may help to explain the linguistic, psychological and behavioural links between social and physical space.