An attempt to prevent the development of a worker--parasite relationship between rats.
D000818:Animals; D001307:Auditory Perception; D001522:Behavior, Animal; D003216:Conditioning, Operant; D004193:Discrimination Learning; D004291:Dominance-Subordination; D004777:Environment; D008297:Male; D051381:Rats; D012055:Reinforcement Schedule; D012201:Reward; D012930:Social Dominance; D014796:Visual Perception