Instability in longitudinal childhood IQ scores of Guatemalan high SES individuals born between 1941-1953
Fig 3
IQ Z-scores across the life course.
IQ Z-scores by age, each line represents an individual. Data to age 17 years comes from the five cognitive tests administered as part of the UVG longitudinal study. Older age data come from the two-minute fluid intelligence test. Raw scores were converted to Z-scores using the sample standard deviations.