We evaluated the effects of a dense (fixed-ratio 1) schedule of reinforceme
nt for an 11-year-old boy's mands for toys while aggression produced the sa
me toys on various schedules chosen on the basis of a progressive-ratio pro
be. Based on the probe session data, we accurately predicted that aggressio
n would be more probable than mands when the schedules were equal or slight
ly discrepant, but that mands would be more probable when the schedule disc
repancy was large.