Following familiarization and magazine training, three groups of rats received either: (1) four food pellets for each of four lever-presses, (2) food for only the first and third lever-presses, or (3) food for only the second and fourth lever-presses. Responding was then extinguished. There were no significant differences between the groups in number of lever presses during extinction or time to extinguish and no significant correlations between these two measures and the number of pellets received during magazine training or the elapsed time to emit the four lever-presses. These data contradict the small-trials partial reinforcement extinction effect commonly reported with the straight alley. However, these data are consistent with those recently reported by Nevin (1985) and with his concept of behavioral momentum, which may apply to the operant chamber but not to the runway.