APA Dictionary of Psychology

an experimental technique in which a nonhuman animal is presented with one or more goals of various drives—for example, food (hunger) versus water (thirst)—and is required to overcome an obstacle (e.g., an electrified grid) in order to reach the goal. The delay before attempting to overcome the obstacle, as well as the animal’s choice of which goal to pursue, may be used to represent drive strength and drive dominance.