The process by which children change from informal speech to proper speech when talking with teachers and most adults is known as switching codes

Before the 1970s, researchers believed that formal operational thought ____

does not develop in many cultures, particularly in cultures that do not have formal schooling || develops much sooner than Piaget proposed, closer to age 9 || develops much faster in girls than in boys because of social- emotional maturity || only develops in the United States, and for unknown reasons it does not develop in other industrialized nations || || ||

Studies of IQ correlations between twins and other relatives show that the average correlation for

A) identical and fraternal twins decreases into adulthood. B) fraternal twins living together is stronger than the average correlation for identical twins living apart. C) twin and nontwin siblings living together is stronger than the average correlation for those living apart. D) fraternal twins living apart is stronger than the average correlation for nontwin siblings living together.