Study of similarities and differences in behavioral organization among living beings.
The discipline pays particular attention to the psychological nature of humans in comparison with other animals. It began to emerge in the late 19th century and grew rapidly in the 20th century, involving experimental studies on human and animal brain function, learning , and motivation . Well-known studies have included those of Ivan Pavlov on conditioning in laboratory dogs, those of Harry Harlow (190581) on the effects of social deprivation in monkeys, and those of various researchers on language abilities in apes.