Serial conditioning as a function of stimulus, response, and temporal dependencies.

Six experiments were used to examine the effects of explicit response, stimulus, and temporal dependencies on responding in an interfood interval. The first two experiments demonstrated that 10-segment 60-s interfood clocks controlled similar distributions of key pecking in pigeons regardless of whether response-reinforcement contiguity was required, allowed, or precluded. The third and fourth experiments found that in the absence of an explicit response-reinforcement dependency, systematic explicit stimuli in an interfood interval were sufficient to establish and maintain the characteristic distribution of key pecking and that an interval without an explicit clock failed to establish or maintain key pecking. The last two experiments demonstrated that the interfood interval need not be of fixed length, and that a simple correlation of stimuli with increments from either a minimum to a maximum imminency or probability of food presentation controlled behavior in a similar manner. Successively higher rates generally occurred to successively later stimuli in the upper half of the range.