Dramatic differences in temperament and activity first become apparent between cultures at what age group?

Question

Quizplus · Accepted Answer

Differences in temperament and activity levels among cultures can be observed as early as the newborn and infant stages. This is because such traits can be influenced by genetic factors, prenatal conditions, and early postnatal environment, all of which vary significantly across different cultures.

Dramatic Differences in Temperament and Activity First Become Apparent Between