To guard against order effects, researchers use

In Piaget's six substages of sensorimotor thought, the tertiary circular reactions occur when the child is _____ months of age

A) 1-4 B) 10-12 C) 12-18 D) 18-24

Which of the following is true of major depressive disorder?

a. Fewer than half of those who suffer an initial major depressive episode will eventually have a recurrence. b. Major depression is never accompanied by psychotic features such as delusions. c. All individuals who experience major depression never have a full return to previous levels of functioning. d. Major depressive disorder can only be diagnosed if the individual began experiencing depressive episodes prior to age 18.