Model, need, and cost effects in helping behavior.
D000704:Analysis of Variance; D003365:Costs and Cost Analysis; D006801:Humans; D007398:Interpersonal Relations; D008297:Male; D008960:Models, Psychological; D010565:Persuasive Communication; D012649:Self Concept; D012919:Social Behavior; D012938:Social Perception; D013637:Tape Recording