A scale for evaluating the behavior and responses of the newborn infant. It is based on four dimensions: interaction with the environment; motor processes, including motor responses, general activity level, and reflexes; control of physiological state as determined by reaction to a distinct stimulus such as a rattle, bell, light, or a pinprick; and response to stress as judged by tremulousness, startle reaction, and change in skin coloration. The test has been used as late as 1 week after birth to demonstrate alteration in an infant’s behavior due to drugs administered to the mother while the infant was in utero.