title: Some sources of variation in the bar-pressing versus freeloading phenomenon in rats.
mesh_terms: D000818:Animals; D003216:Conditioning, Operant; D004435:Eating; D005247:Feeding Behavior; D005260:Female; D011214:Practice, Psychological; D051381:Rats; D012055:Reinforcement Schedule; D012201:Reward; D013997:Time Factors