Behavioral contrast and decreasing preference for a multiple-schedule component with reduced response rate

When responding in one component of a multiple schedule of reinforcement is suppressed, behavioral contrast, indicated by an increase in response rate, may occur in an alternated, unchanged component. The present study attempted to determine whether the suppression of responding that produces contrast does so because it renders the component in which it occurs aversive relative to the unchanged component. Six pigeons were exposed to a multiple fixed-interval fixed-interval schedule of reinforcement with equal reinforcement rates in the two components, and, on alternate days, to a concurrent chain schedule having terminal links identical to the components of the multiple schedule. When responding was suppressed in one multiple-schedule component and in one terminal link, three subjects showed positive contrast in the unchanged multiple component and indicated decreased preference for the terminal link in which responding was suppressed. Two additional subjects showed no contrast in the multiple schedule and increased preference for the terminal link in which responding was suppressed