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. Are these assumptions justified? 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. Many of these findings involve domains that are associated with fundamental aspects of psychology, motivation, and behavior - hence, there are no obvious a priori grounds for claiming that a particular behavioral phenomenon is universal based on sampling from a single subpopulation. 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. We close by proposing ways to structurally re-organize the behavioral sciences to best tackle these challenges.

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The WEIRDest People in the World

The Pharmacological Basis of Therapeutics A Textbook of Pharmacology, Toxicology and Therapeutics for Physicians and Medical Students. By Prof. Louis Goodman and Prof. Alfred Gilman. Pp. xiii + 1383. (New York: The Macmillan Company, 1941.) 50s. net.

The Pharmacological Basis of Therapeutics

Varieties of numerical abilities.

Observing Interaction: An Introduction to Sequential Analysis, Roger Bakeman, John M. Gottman. Cambridge University Press, Cambridge (1986), ixv, +221. Price £25.00 hardback, £7.95 paperback

The conditions of learning

Two experiments were conducted to assess the referential function of chimpanzee (Pan troglodytes) gestures to obtain food. The chimpanzees received 1 trial per condition. In Experiment 1 (N 101), in full view of the chimpanzee, a banana was placed on top of 1 of 2 inverted buckets or was hidden underneath 1 of the buckets. In Experiment 2 (N 35), 4 conditions were presented in constant order:(a) no food, no observer; (b) no food, observer present; (c) food present, no observer; and (d) food present, observer present. Gestures and visual orienting were used socially and referentially. The capacity for nonverbal reference may predate the HominidaePongidae split, and the development of nonverbal reference may be independent of human species-specific adaptations for speech.

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Referential communication by chimpanzees (Pan troglodytes).

The goal was to suggest a meaningful approach to the assessment of intelligence which may be used, for example, in correlational studies with measures of encephalization. Suggesting, as others have done, that species comparisons based on quantitative differences inherently confound intellective with nonintellective abilities, the present approach described a hierarchy of 8 basic levels of qualitatively different intellective (learning) abilities. The levels range from habituation to complex concepts. Practical procedures and strategies which, ancrease the precision of the scale were described.

Evolution of Intelligence: an Approach to Its Assessment

Two monkeys were reinforced for responding to the card which displayed fewer number of entities (three randomly selected sizes of filled circles) than the other card in any given pair. Area and brightness cues were controlled (at least for the successive numerousness discriminations), as were specific-pattern learning cues. Training proceeded in the order 2 versus 7 (2:7), 2:6, 2:5...2:3, 3:7, 3:6...3:4, etc., until it was judged that the monkeys were unlikely to attain the stringent criteria for discrimination. Both monkeys met criteria on the 7:8 discrimination, and one monkey met criteria on the 8:9 discrimination. It was concluded that the monkeys' numerousness judgments were made on a conceptual basis and that, among nonhuman animals, the evidence for such judgments appears to be limited to apes and monkeys.

https://www.jstor.org/stable/info/1422230

Conceptual numerousness judgments by squirrel monkeys.

Effects of substantia nigra and caudate nucleus lesions on avoidance learning in rats.

With nonnumerousness dimensions (e.g., pattern, area) controlled, three cards with two to seven black-filled circles were presented on each trial. If the center of three conditional cue lights was illuminated, the monkey was reinforced for selecting the card with the fewest circles; if two lights were on, the card with the intermediate number of circles was correct; and if three lights were on, the card with the most circles was correct. Training began with one conditional cue light and proceeded to the three-light condition. Then the one- and three-light conditions were presented randomly and concurrently, followed by the two-light condition. Finally, one, two, or three lights were presented randomly and concurrently. Only one monkey met criterion on all training stages, but another monkey succeeded also through the intermediate-number condition. It was concluded that the squirrel monkey is capable of relative numerousness judgments, including ordinal numerousness judgments. Additional discussion was concerned with the hypothesis suggested by Brown, Lenneberg, and Ettlinger (1978) that the ability to use quantitative concepts is a prerequisite to the acquisition of language.

/pdf/relative-numerousness-judgments-by-squirrel-monkeys-4auczpk341.pdf

Roger K. Thomas

Papers

Referential communication by chimpanzees (Pan troglodytes).

Evolution of Intelligence: an Approach to Its Assessment

Conceptual numerousness judgments by squirrel monkeys.

Effects of substantia nigra and caudate nucleus lesions on avoidance learning in rats.

Relative numerousness judgments by squirrel monkeys