What term do psychologists use for the phenomenon that occurs when people are less likely to aid a person in trouble if there are other people around who are also potential helpers?

Imagine that you are looking at a geometric drawing. At first, one shape in this drawing seems to be in front of other shapes. The next moment, this same shape seems to be located behind a second shape. This phenomenon is called:

a. depth perception. b. an illusory contour. c. an ambiguous figure-ground relationship. d. holistic recognition.

Three-year-old Arya handed his mother three bananas. She asked him if he would like to eat a banana. His response was, "Yes, I want to make it two." Contrary to Piaget, Arya seems to have a clear understanding of

a. numbers. c. relationships. b. objects. d. identity.