People as diverse
Cross-cultural Psychology (CCP) is trying to determine how sociocultural variables influence human behaviour; to do so, it sometimes focuses on behavioural differences across cultures, and sometimes on universal patterns of behaviour. Most of the research that's been conducted under the banner of CCP has presupposed the categories and models of mainstream Psychology involving Euro-American populations. The distinction between universal and culture-specific behaviour is one version of what's come to be known in CCP as the emic–etic distinction. According to the perspective of Cultural Psychology, culture influences which behaviours are considered to be intelligent, the processes underlying intelligent behaviour, and the direction of intellectual development. Psychological theories of intelligence must offer accounts that are relative to a particular time and context. Galton proposed a research design in which the intelligence of adopted relatives is compared with that of biological relatives, predicting that the latter should be far more alike than the former.