ABSTRACT
Chronological age, gender, race/ethnicity, nationality, culture, urban/rural residence, education, SES, family size, birth order, and historical era are some of the demographic variables that have been related to scores on tests of intelligence and special cognitive abilities. Fluid ability is conceptualized as inherent, genetically determined cognitive ability as manifested in problem solving and novel responses. The greatest amount of research concerned with intelligence was conducted by specialists in either psychometrics or developmental psychology, although much research on cognitive abilities was purely empirical and not inspired by any theory. Of all psychological and the educational measuring instruments, the highest reliabilities, often in the.90s, have been obtained with tests of the cognitive abilities. Among the health disorders that can have pronounced effects on cognitive functioning in later life are Alzheimer's disease and hypertension. Observations of age of talking, walking, or other cognitive and perceptual-motor skills have proved no better than infant intelligence tests in predicting later cognitive development.
