Olds and Milner (1954) were the first to provide a complete report of intracranial self-stimulation behavior.

Motion parallax

a. is not enough, alone, to indicate depth when most other cues fail. b. refers to the illusion that distant objects move slightly against a background, while closer objects move a sizable distance. c. is responsible for motion sickness. d. is dependent on stereoscopic vision.

Child abuse is more likely to occur when

a. children are infants or preschoolers than when they are older. b. children are healthy. c. parents have frequent contact with and receive help from friends and relatives. d. parents have low expectations for their children.