Effort as a determinant of choice in rats.
D000818:Animals; D003216:Conditioning, Operant; D004326:Drinking; D004327:Drinking Behavior; D005108:Extinction, Psychological; D005247:Feeding Behavior; D006799:Housing, Animal; D008297:Male; D005082:Physical Exertion; D011336:Probability; D051381:Rats; D012055:Reinforcement Schedule