A reasonable explanation for why 40-year-olds and 60-year-olds show differences in intelligence test scores is:

Question

Quizplus · Accepted Answer

Cohort effects refer to the fact that individuals who were born and raised in different historical periods may have had different experiences that affect their intellectual development. For example, 60-year-olds may have had more access to education and technology than 40-year-olds, which could explain the difference in test scores. Secular trends (A) refer to gradual changes in intelligence across birth cohorts, but this is unlikely to explain a difference of only 20 years. Declining IQ with age (C) is a controversial topic, with some evidence suggesting a decline and others suggesting stability or even improvement with age. Biases in IQ testing (D) may also contribute to differences between age groups, but again, cohort effects are likely to play a larger role.

A Reasonable Explanation for Why 40-Year-Olds and 60-Year-Olds Show Differences