Cognitive science has two main branches, one primarily physiological and one primarily psychological. The interests, methods, and outcomes of the approaches are so different that it may be a mistake to consider them together. But many people do, with predictable confusion and miscomprehension.
The physiological approach to cognitive research focuses on how the brain works. Investigators use CAT scans and other measurements to track the physical structures at work in the brain and the physiological changes that occur when the brain is handling different kinds of problems and doing different kinds of work. The psychological approach to cognitive research focuses on what the subject does. Investigators use games and other observations to track the mental responses of the brain to different stimuli and situations.
The empirical results of cognitive physiology can be applied to any similarly equipped brain. Since human brain physiology is universal, these results are relevant across our species. But what about the results of psychological cognitive research?
A recent article by researchers at the University of British Columbia suggests that while the physiology of the brain is universal, the psychology of human cognition may not be. If they are right, the implications for cognitive research could be large indeed. Psychologist Joseph Heinrich and his colleagues have published “The weirdest people in the world?” in the journal Brain and Behavioral Sciences.
The article’s main point is that because the vast majority of psychological studies of such human behaviour as morality, motivation and perception use subjects from Western industrialized countries almost exclusively, the results of these studies may not be an accurate reflection of a universal human nature:
Behavioral scientists routinely publish broad claims about human psychology and behavior in the world’s top journals based on samples drawn entirely from Western, Educated, Industrialized, Rich, and Democratic (WEIRD) societies. Researchers – often implicitly – assume that either there is little variation across human populations, or that these “standard subjects” are as representative of the species as any other population.
Heinrich’s own research suggests that these assumptions may be false. The “Ultimatum Game” is a situation in which one player is given $100 and told that to keep any part of it he must offer a portion to a second player, who must accept the offer or both players get nothing. When the game is played with WEIRD subjects, the average offer by player #1 is $48, and on average player #2 will refuse any offer below $40. Yet when the game was played with Amazonian tribesmen, the results were quite different. First, the tribesmen thought that offering half of the money to another was unreasonably generous. Second, the tribesmen typically would accept even small offers, thinking it unreasonable to turn down free money, no matter how little. WEIRD and Amazonian tribesmen subjects displayed strikingly different conceptions of fairness and sharing.
Even “simple” tests of physical perception produced different results with different subject groups. We’re all familiar with the Muller-Lyer optical illusion:
Even though we know that the parallel lines are of equal length, they don’t look that way to us. But to Kalahari hunter-gatherers, there is no illusion — they see the lines as of equal length. Why? The typical explanation is that since we WEIRD subjects live in a world of artificial straight lines and congruent geometric angles, we see the lines in conjunction with the angles they make with the arrows, rather than entirely separately.
Heinrich and his colleagues went on to make a survey of behavioural science studies and found that fully 96% of the subjects tested were WEIRD. And in study after study, the WEIRD subjects produced results which were not reproducible in studies using subjects from the 88% of the world’s population who are not WEIRD:
Here, our review of the comparative database from across the behavioral sciences suggests both that there is substantial variability in experimental results across populations and that WEIRD subjects are particularly unusual compared with the rest of the species – frequent outliers. The domains reviewed include visual perception, fairness, cooperation, spatial reasoning, categorization and inferential induction, moral reasoning, reasoning styles, self-concepts and related motivations, and the heritability of IQ. The findings suggest that members of WEIRD societies, including young children,
are among the least representative populations one could find for generalizing about humans. …
Overall, these empirical patterns suggests that we need to be less cavalier in addressing questions of human nature on the basis of data drawn from this particularly thin, and rather unusual, slice of humanity.
Does this mean that cognitive psychology can’t tell us anything useful about the human species as a whole? Not necessarily, as there is good evidence that all cultures manifest
the same core psychological impulses — a sense of fairness, a desire for purity, a bias to find agencies (including gods) in our environments, etc. We all have an impulse to create gods, but we won’t all create the same one. We all have a sense of fairness, but what fairness means will differ from one group of cultures to another.
It seems that the specific results of many psychological studies, no matter how rigourous their components, may be of limited application thanks to the different environmental and cultural experiences of their subjects. This is a restriction that simply does not arise in physiological cognitive research, and that it does not vividly points out a major difference between empirical science and behavioural interpretation. It can reasonably be argued that this difference identifies an unbridgeable gap between the two primary approaches to cognitive investigation.
And it could be just this gap which explains why postmodernist relativism has had so strong an influence in the behavioural sciences, and why that same relativism cannot be applied to the empirical realm of cognitive brain research — or, for that matter, to any of the physical sciences.