The Studies with the Strongest Research Methodology Related to the Effect

Multiple Choice

The studies with the strongest research methodology related to the effect of age on intelligence test scores indicates that intelligence:

A) is stable over the life-span and can be accurately measured in preschool children.
B) gradually declines after the age of 20, with the decline becoming more apparent after 50.
C) is mostly stable throughout adulthood with little variation until death.
D) is mostly stable throughout adulthood with slight declines after 65 in the area of fluid intelligence.