An evolutionary rationale for blushing.

An article from Benedict Carey covers work suggesting the blushing evolved to to strengthen social bonds.

Gender, culture, and mathematics performance

Janet Hyde at Wisconsin continues her crusade against the proposition that there are gender differences in mathematical performance and talent. (Unfortunate comments on this issue got Larry Summers fired - or more accurately, he 'resigned under pressure' - as Harvard President.)

Unconscious motor control that conflicts with conscious awareness.

During my recent Europe vacation, on stepping onto an escalator in the Munich metro that I knew was stopped, I noticed that odd sensation accompanied by clumsy movements that is probably also familiar to you, as if my motor behavior and sensations were being guided by a “phantom” of a moving escalator. Fukui et al. show that this is the consequence of an unconscious automatic habitual motor program cued by the escalator itself. Their results suggest a dissociation between conscious awareness and subconscious motor control: the former makes us perfectly aware of the current environmental situation, but the latter automatically emerges as a result of highly habituated visual input no matter how unsuitable the motor control is.

Boosting your serotonin reduces responsiveness to aggression

From Berman et al.:

We tested the theory that central serotonin (5-hydroxytryptamine, or 5-HT) activity regulates aggression by modulating response to provocation. Eighty men and women (40 with and 40 without a history of aggression) were randomly assigned to receive either 40 mg of paroxetine (to acutely augment serotonergic activity) or a placebo, administered using double-blind procedures. Aggression was assessed during a competitive reaction time game with a fictitious opponent. Shocks were selected by the participant and opponent before each trial, with the loser on each trial receiving the shock set by the other player. Provocation was manipulated by having the opponent select increasingly intense shocks for the participant and eventually an ostensibly severe shock toward the end of the trials. Aggression was measured by the number of severe shocks set by the participant for the opponent. As predicted, aggressive responding after provocation was attenuated by augmentation of serotonin in individuals with a pronounced history of aggression.

Questioning the link between brain size and sociality

Almost any lecture on brain evolution includes the assertion that larger brains evolved to serve communication demands of larger social groups. Finarelli and Flynn question this for the carnivores (cats, dogs, bears, weasels, and their relatives).

Anticipating monetary and social reward - differing brain activations in men and women.

Spreckelmeyer et al. show a wider network of brain regions is activated by the prospect of monetary reward in men than in women.

Lost in the sauce - alcohol and mind wandering

Great.... all I need is another reason to question the daily happy hour that I use to take the edge off the TV evening news. From Sayette et al:

Alcohol consumption alters consciousness in ways that make drinking both alluring and hazardous. Recent advances in the study of consciousness using a mind-wandering paradigm permit a rigorous examination of the effects of alcohol on experiential consciousness and metaconsciousness. Fifty-four male social drinkers consumed alcohol (0.82 g/kg) or a placebo beverage and then performed a mind-wandering reading task. This task indexed both self-caught and probe-caught zone-outs to distinguish between mind wandering inside and outside of awareness. Compared with participants who drank the placebo, those who drank alcohol were significantly more likely to report that they were zoning out when probed. After this increase in mind wandering was accounted for, alcohol also lowered the probability of catching oneself zoning out. The results suggest that alcohol increases mind wandering while simultaneously reducing the likelihood of noticing one's mind wandering.

Mathematical and linguistic syntax: different brain areas

Contra the suggestion of Hauser, Chomsky, and Fitch that the hierarchical processing required for syntactical operations requires Broca's area, central to language, Friedrich and Friederici find MRI evidence that syntactic processing of abstract mathematical formulae involves mainly intraparietal and prefrontal regions:

Theory predicts a close structural relation of formal languages with natural languages. Both share the aspect of an underlying grammar which either generates (hierarchically) structured expressions or allows us to decide whether a sentence is syntactically correct or not. The advantage of rule-based communication is commonly believed to be its efficiency and effectiveness. A particularly important class of formal languages are those underlying the mathematical syntax. Here we provide brain-imaging evidence that the syntactic processing of abstract mathematical formulae, written in a first order language, is, indeed efficient and effective as a rule-based generation and decision process. However, it is remarkable, that the neural network involved, consisting of intraparietal and prefrontal regions, only involves Broca's area in a surprisingly selective way. This seems to imply that despite structural analogies of common and current formal languages, at the neural level, mathematics and natural language are processed differently, in principal.

Money, social distress, and physical pain

The Symbolic Power of Money: Reminders of Money Alter Social Distress and Physical Pain

Aging, isolation, and internet social networks

An article by Stephanie Clifford on isolated older adults finding social sustenance through internet social sites.

Why we pig out.

Parker-Pope describes how the food industry combines and creates foods in a way that taps into our brain circuitry to stimulate our desire for more.

Do we trust our eyes or our ears?

Interesting Angier article on our visual versus sound time resolution, and how situations with conflicting visual and auditory stimuli are resolved. You can hear 20 clicks per second, but twenty visual frames per second is a movie.

Models of life's origins - great videos

Check out Wade's article that has, and links to, some great videos illustrating how a synthetic cell might be made by getting a protocell formed of lipids and a genetic molecule to grow and divide in parallel, with the molecules being encapsulated in the cell. If the molecules gave the cell a survival advantage over other cells, the outcome would be a sustainable, autonomously replicating system, capable of Darwinian evolution.

Gene for depression debunked...

Benedict Carey writes on how a compelling study showing a correlation between a particular variant of a gene involved in Serotonin regulation and the probability of sinking into depression after a stressful event has not been replicated. A coalition of researchers identified 14 studies that gathered the same kinds of data as the original study. They reanalyzed the data and found no evidence of an association between the serotonin gene and the risk of depression, no matter what people’s life experience was.

Zap your brain to enhance your planning ability

Enhancement of Planning Ability by Transcranial Direct Current Stimulation.

Prayer in devoutly religious people recruits social cognition brain areas.

Schjoedt et al. suggest that praying to God is an intersubjective experience comparable to ‘normal’ interpersonal interaction.

Back from vacation - A new variety of MindBlog post....reader poll.

Back from vacation...I had thought that a sudden halt in the daily habits surrounding blog production might cause some withdrawal symptoms. But no... nothing, zip. Now I face a very long accumulated list of potential post topics, which brings home the point that my ritual of doing two blog posts per day forces me to choose only a fraction of the articles that I find interesting as I scan the tables of contents of a number of journals. Among those discarded articles are many that I am sure a subset of MindBlog readers would like to be aware of, even if only given a minimal description of content along with the link to the journal. So, for the next week or two at least, I am going to experiment with sprinkling in more tiny posts, in much the same way that Andrew Sullivan's blog does. The reason for making each a separate post is that the titles then appear in the list presented by RSS readers. (On a typical weekday there are ~200-250 significant post viewings, out of ~1,150 RSS feed subscribers.)

I can think of arguments against doing this (overload, spamming), so I would be grateful for feedback on whether readers think this is a good or bad idea. How many topics/day would you find most useful?

Stress triggers our habitual behaviors

Schwabe and Wolf at Ruhr University in Bochum show that stress promotes habits at the expense of goal-directed performance in humans. Converging lines of evidence show that stress and the glucocorticoid stress hormones (mainly cortisol in humans) released from the adrenal cortex can operate as a switch between "cognitive" (mediated by prefrontal cortex) and "habit" (mediated by striatum)learning systems.

You want to know the truth? Then don't mimic!

We usually feel that expressing empathy by mimicking another person's face and body movements facilitates our understanding of their true emotions. Not so, apparently, if they are lying. Stel et al. have done experiments with two interacting people as follows:

...targets either lied or told the truth, while observers mimicked or did not mimic the targets' facial and behavioral movements. Detection of deception was measured directly by observers' judgments of the extent to which they thought the targets were telling the truth and indirectly by observers' assessment of targets' emotions. The results demonstrated that nonmimickers were more accurate than mimickers in their estimations of targets' truthfulness and of targets' experienced emotions. The results contradict the view that mimicry facilitates the understanding of people's felt emotions. In the case of deceptive messages, mimicry hinders this emotional understanding.

Economy still at the brink

I found this article by two professional Wall Street traders (one out of prison, pardoned by Clinton), to be fascinating.