Week 13, post 1

In chapter 21, I found it interesting that there was a study conducted among people of the same genes but varying ages. This study had 1,191 carefully selected individuals from ages 10 to age 90. The results showed that IQ rose from age 10-18, peaked between ages 18 and 21, and gradually fell until by age 55 where the same IQ was the same by age 14. On the other hand, in a longitudinal research study, Nancy Baylet and Melita Oden studied children with gifted intellects and found there IQ increased from age 20-age 50 (Berger, p. 580). Comparing and contrasting the study methods of IQ testing (Cross-sectional verses Longitudinal); Validity of the two forms of measurement varies. This is partly due to influential factors such as younger individuals tend to have a higher IQ education, advantages of cultural advancements (new sources of information, modes of travel) and environmental factors (health, childhood nutrition, and other environmental influences) (Berger, p. 580). In addition, strong cohort effects and life experiences have influences over IQ differences in generations as well. The validity of a correlational study isn’t the same as a longitudinal study because even though older individual’s score lower than younger individuals, this does not mean older adults lose intellectual power. In a correlational study, the younger generation scored higher than the previous generation. Whereas in the longitudinal study, adults score improves with each re-testing (but this may be due to consistent practice of testing improves test scores). According to researchers longitudinal studies are more accurate for studying IQ because they show development.