After training on a multiple variable-interval variable-interval schedule of reinforcement, each response in one component of the schedule was followed by a brief electric shock. When the rate of punished responses stabilized, the frequency of reinforcement in the other component was first decreased and then increased from the baseline frequency. The effects of these manipulations were consistent with reports of interactions in multiple schedules involving only unpunished behavior, i.e., the rate of punished responses increased with a higher relative frequency of reinforcement in the punishment component and decreased with a lower relative frequency of reinforcement in that component. The relevance of such findings to a further generality of behavioral contrast effects is discussed.Frequency of reinforcement may be stated in either absolute or relative terms. In the latter case, multiple schedule components often provide the basis for comparisons between behavioral effects of different reinforcement frequencies. Changes in the absolute frequency of reinforcement in one component of the multiple schedule, while leaving absolute reinforcement frequency in the other component(s) unchanged, also alters the relative frequency of reinforcement in these unchanged components. Beginning with Reynolds (1961a, b, c; 1963) a number of investigators have assessed the behavioral effects of such changes (e.g., Bloomfield, 1967;Catania and Gill, 1964;Nevin and Shettleworth, 1966 avoidance behavior in a second component associated with a constant response-shock interval (Wertheim, 1965). The rate of unpunished responses in one component of a multiple schedule is also sensitive to manipulations in the intensity of a punishing stimulus delivered after each response in a second component. Such increments in unpunished responding do not necessarily result from a change in the relative frequency of reinforcement, but they have been interpreted as being similar to the behavioral contrast effects brought about by manipulations in the relative frequency of reinforcement (Brethower and Reynolds, 1962