Behavior: Blue Is Beautiful

Psychologists and toy manufacturers have between them devised a bewildering variety of educational toys for the crib and playroom. But the way to fire a youngster's intelligence and imagination, according to a three-year study recently finished in Germany, is to put him in a large, low-ceilinged room painted in his favorite color.

Colors, particularly, have "a decisive influence on the child's mental performance," says Henner Ertel, director of Munich's Gesellschaft für Rationelle Psychologie, where researchers have been studying the impact of environment on mental growth since 1970. Indeed Ertel and his co-workers found...