Sunday, November 25, 2007

Interesting research, in brief

Occasionally I will summarize (but not analyze) a handful of attention-grabbing recent research findings and link to the original papers so interested readers can follow up for themselves. Sometimes I might go on to write a more thorough analysis of particular papers mentioned in my “in brief” posts.


The first study that caught my eye was that, apparently, elephants stereotype. I'm editorializing, of course, but according to research published in Current Biology, elephants distinguish between different human ethnic groups. In the Amboseli Reserve, in Kenya, elephants sometimes encounter Maasai men who attempt to prove their virility by spearing them. The Kamba ethnic group, on the other hand, are apparently generally nice to the elephants and let them be. As a result, "Elephants showed greater fear when they detected the scent of garments previously worn by Maasai than by Kamba men, and they reacted aggressively to the color associated with Maasai. Elephants are therefore able to classify members of a single species into subgroups that pose different degrees of danger."

The second interesting recent animal study tested a counter-argument to the hypothesis that chimpanzees have culture (or engage in differential "social learning"). Observed behavioral differences between non-interacting chimp troops, so this counter-argument runs, could be due to genetic differences between the groups and therefore may not be attributed to cultural variation.
The study, published in PNAS, conducted a cladistic analysis comparing the phylogeny and behavior of different groups. The conclusion? "These findings are inconsistent with the hypothesis that patterns of behavioral differences at the population level are genetically determined. Instead, they are in line with a growing number of studies involving captive groups and wild populations that suggest many chimpanzee behaviors are socially learned and can be considered cultural."


Far from corrupting the youth, philosophy may in fact be good for children. Research published in Educational Psychology suggests that lessons consisting of a Socratic dialogue between students and a teacher has long term cognitive benefits. This finding is a follow-up on the same authors' earlier study which found 16 months of weekly 1 hour philosophy lessons "showed significant standardized gains in verbal and also in non-verbal and quantitative aspects of reasoning" whereas controls showed no gains. Two years later, the researchers tracked down 96 experimental and 52 control subjects and re-administered the cognitive performance tests. They found that "the significant pre-post cognitive ability gains in the experimental group in primary school were maintained towards the end of their second year of secondary school" whereas "the control group showed an insignificant but persistent deterioration in scores from pre- to post-test to follow-up." As far as I am aware, only the International Baccalaureate curriculum incorporates philosophical training at school-level (and then not early enough). Given these findings, that's quite a shame. (See also BPS Research Digest's report on this research).

In possibly the most interesting study I've seen for a while,
Bruce Ellis and Marilyn Essex test a life history model of menarche. In an influential 1991 paper, "Childhood experience, interpersonal development, and reproductive strategy," Belsky, Steinberg and Draper proposed the psychosocial acceleration theory which holds (among other things) that girls adaptively adjust their onset of puberty based on the quality of paternal investment and other factors reflecting their living conditions. Ellis and Essex set out to test this theory comprehensively by following 570 pregnant women and their partners longitudinally and determing the effect of socio-economic status, marital conflict, parental mental illness, parental investment (inter alia) on the age of menarche in their children. Their conclusion is that the "quality of parental investment... is the most important mechanism through which young children receive information about levels of stress and support in their local environments, and that this information provides a basis for adaptively adjusting pubertal timing." (See also ScienceDaily's report on this research).


It has been known for some time that "emotion drives attention"; that biologically significant stimuli (snakes and spiders being the classic examples) capture the attention of animals (including humans) much quicker than non-biologically significant stimuli. The focus of this literature, however, has been primarily on threatening biological stimuli; a category arguably much narrower than biologically significant stimuli. Now Tobias Brosch, David Sander, and Klaus Scherer argue in their new study that humans also pay preferential attention to newborn infants. The authors suggest, furthermore, that their "results support the notion that a common evaluative process may be responsible for the emotional modulation of selective attention to both negative and positive affectively arousing stimuli."

According to research just released in Nature, infants as young as 6 months have such a well developed theory of mind that they take individuals' behavior towards others into account when forming preferences. Using a methodology involving an innovative puppet show, the authors show that "
infants prefer an individual who helps another to one who hinders another, prefer a helping individual to a neutral individual, and prefer a neutral individual to a hindering individual" and conclude their finding "supports the view that social evaluation is a biological adaptation." (See also Nature News's article on this research).


  1. Now if you could just do this everyday and expand your coverage well beyond ev psych...

    In all seriousness, very nice.


  2. Yeah, nice one. You're smart - you should write a thesis or something.

  3. John - I'd love to produce this much stuff per day. Alas, I would do little else. :-)... but thanks.

    David - yeah, that's quite a good idea. Maybe I should consider it...

  4. Personally, I'd prefer lots more of this stuff to a thesis. David's clearly biased whereas I can be perfectly objective.