They compare people of different ages.

resulted in women increasing their sexual activity.

focusing attention on what they are eating.”

different characteristics of a given individual are assessed at the same time.

has been standardized on a representative sample of all those who are likely to take the test.”

similar to those of their adoptive siblings.

forming and strengthening one’s neural pathways.

an originally neutral stimulus that comes to trigger a conditioned response.”

adult memories of experiences happening before age 4 are unreliable.”

They compare the same people over an extended length of time.”