Mental disorders are almost always influenced by multiple genes. This means they are

Research has found that providing external reinforcement reduces intrinsic motivation. This phenomenon is known as the _____ effect.

A. no free lunch B. Lake Wobegon C. overjustification D. growth need strength

Which of the following statements about playing games in middle childhood is true?

A) Child-invented games are usually contests of individual ability. B) Gains in perspective taking permit a transition to rule-oriented games. C) School-age children today spend more time engaged in informal outdoor play. D) For most children, joining community sports is associated with decreased self-esteem.