PSYC 1200 Lecture 6b
Chapter 9: IQ Test vs. Other Conceptions of Intelligence
Problems with IQ Culturally Biased Questions: white, middle to upper class urban kids/adults do better than members of other groups because the
Scores questions are most appropriate for them.
Generalizability: someone‟s IQ Score is influenced by situational factors (e.g. didn‟t eat, lack of sleep, having other things on your
Validity The extent that a test measures what it is meant to measure.
IQ Score ‘Predictive’ or ‘Criterion’ Validity:
In general, higher IQ scores = higher grades in high school and university = higher success in the workplace
Reliability The extent that a test of some attribute will provide the same score for a person each time it is administered.
IQ Score Reliability: There is much consistency in people‟s IQ scores from age 21-60, declining somewhat thereafter.
IQ Score A measure of innate mental ability (i.e. genetics/nature) or the quality of a person‟s experiences (i.e. the environment/nurture).
Heritability of IQ scores is 0.60 to 0.80 in adults (60% to 80% of differences in IQ are due to genetics).
Culturally-biased questions are only part of the problem; it is the social environment that is unfair, not the tests.
IQ Scores measure exposure to environments that foster learning and mental development.
Twin Studies of IQ scores of Identical twins raised in different environments are more highly correlated (0.72) than scores of fraternal twins raised
Intelligence together (0.62); therefore, the contribution of genetics overshadows the contribution of shared environment.
Adoption Studies of IQ scores of non-twin siblings are more correlated (0.47) than IQ scores of adopted, but unrelated siblings (0.30); therefore, the
Intelligence contribution of genetics beats the contribution of shared environment.
Environment Factors Prenatal Care, nutrition during childhood, exposure to toxins (e.g. lead paint), family stress, degree of mental stimulation in
Involved in IQ childhood (all of which drop a child‟s IQ points by 4 on average and are associated with poverty).
Beyond IQ IQ scores do correlate with success in life as predicted by amount of education, income, etc., but even some people with off the
charts IQ fail miserably in this regard and the difference appears to be motivation.
Lew is Terman (1921) Found that the top 100 most successful child prodigies had an average IQ that was identical to the least successful 100. Their
difference in success was motivation.
The Role of Cultural 96% of Chinese and 90% of Japanese children have higher math scores than the average North American child, yet environment
Attitudes and Beliefs favours the North American Kids (since Chinese students have higher class sizes and poorer facilities) and IQ i