Why We Conform - Michael Tomasello

Here is a review in PLoS Biology of Mike Tomasello's latest book - written by Leipzig colleague Julia Fischer. Here are the first two paragraphs:

What makes us human, what sets us apart from other animal species, and which traits do we share with our closest living relatives? Ever since Darwin introduced the notion of continuity in his theory of evolution, humans have been obsessed with the question of how to distinguish themselves from all other species. In the postwar period, our species became known as “Man the Toolmaker,” until in the 1960s Jane Goodall watched chimpanzees using sticks to fish for termites, and that was that. We then distinguished ourselves using the term “Man the Hunter,” but the discovery that chimpanzees and other social carnivores engage in coordinated hunts refuted this type of collective action as the one decisive feature. More recently, the issue of culture has entered center stage. Trying to distinguish the cultural “haves” from the “have-nots” tends to generate more heat than light, and it seems much more productive to think about the cognitive prerequisites for social learning, attribution of mental states, and symbolic communication.

In his book Why We Cooperate, Michael Tomasello explores the socio-cognitive mindset that forms the basis of human sociality, including the creation of cultural artifacts and social institutions. The key message is that humans are fundamentally helpful and cooperative, as evidenced by infants' willingness to provide information, help, and share worldly goods. Later in life, experience may corrupt this benevolent attitude, but the core point for Tomasello is that children exhibit other-regarding preferences, and it is precisely this feature that sets them apart from our closest living relatives, the great apes.

Chimps Can Estimate A Full Pint!

Very interesting article from the BBC on the apparent ability of chimps to estimate volumes of liquid from the visual evidence of it being poured into containers. In other words they can track continuous quantities, like pouring liquid, not just finite quantities like pieces of fruit etc. As the article explains:

In the first experiment, Dr Beran poured quantities of fruit juice from a 600ml syringe into a clear cup and opaque cup. The chimps watched as he did so, and then choose the larger to drink. It did not matter if Dr Beran poured 100ml, 200ml, 300ml or so on up to 600ml into either cup (one UK pint = 568ml). More than three quarters of the time, the chimps would select the larger volume.

Crucially, by pouring the liquid into opaque containers, the chimps could only see how much was being poured, not how much had accumulated in the measuring cup. That means the chimps could accurately visualise or understand how much liquid was being poured, rather than collected.

"They had to watch juice pour into containers and once the juice was there, it was out of sight. So they had to remember how much juice is there, just from seeing it fall," Dr Beran told the BBC.

There was more:

In a second set of experiments, the chimps had to choose between a clear cup already containing a certain volume of juice, and another they couldn't see, but into which was poured a drink. That meant the chimps could not take the relatively easy option of timing the pouring events, and choose whichever cup had liquid poured into it for longer.

"This is a complicated feat because there are no cues such as duration of pouring or height of the liquid that can be used," explains Dr Beran. "They must represent and compare the poured amount to the visible amount, and estimate which is larger."

Again the chimps easily appreciated the difference.

Beran's results are really the first to strongly argue that chimps, in one domain at least, have a grasp of folk physics.

Dopamine Transporter Gene And Modern Human Behaviour

In my chapter THE APE THAT DOMESTICATED ITSELF I detail work on variants of the dopamine receptor gene that seem implicated in either warlike, aggressive societies, or those that have shown prowess for migration, against more peaceful societies. Here a group of scientists have looked at a related gene, the dopamine transporter gene, and shown that certain variants of it confer protection against a number of risky behaviors, especially at an age when those behaviours are deemed illegal. See their abstract below:

"This study tests the specific hypothesis that the 9R/9R genotype in the VNTR of the dopamine transporter gene (DAT1) exerts a general protective effect against a spectrum of risky behaviors in comparison to the 10R/9R and 10R/10R genotypes, drawing on three-time repeated measures of risky behaviors in adolescence and young adulthood on about 822 non-Hispanic white males from the Add Health study. Our data have established two empirical findings. The first is a protective main effect in the DAT1 gene against risky behaviors. The second finding is that the protective effect varies over age, with the effect prominent at ages when a behavior is illegal and the effect largely vanished at ages when the behavior becomes legal or more socially tolerated. Both the protective main effect and the gene-lifecourse interaction effect are replicated across a spectrum of most common risky behaviors: delinquency, variety of sexual partners, binge drinking, drinking quantity, smoking quantity, smoking frequency, marijuana use, cocaine use, other illegal drug use, and seatbelt non-wearing. We also compared individuals with the protective genotype and individuals without it in terms of age, physical maturity, verbal IQ, GPA, received popularity, sent popularity, church attendance, two biological parents, and parental education. These comparisons indicate that the protective effect of DAT1*9R/9R cannot be explained away by these background characteristics. Our work demonstrates how legal/social contexts can enhance or reduce a genetic effect on risky behaviors."