Integration in response timing: The functional time requirement

Two procedures involving differential reinforcement of the duration of fixed-ratio sequences required pigeons to choose between simultaneously available duration requirements. One variation demanded only that the ratio durations exceed a lower limit; the second entailed an upper limit as well. In the no-upper-bound conditions, ratio duration was influenced by the other choice option. The larger the difference between the two duration requirements, the more ratio duration in one component shifted in the direction of the other requirement. The upper-bound procedure weakened this interaction. The temporal differentiation equation—an equation that has successfully described the effects of single time requirements on a variety of species and response units—fit the present results when the functional time requirement was viewed as the weighted average of the component requirements. The weighting parameter determining the functional requirement was influenced by the presence or absence of the upper bound. As has proven generally the case in temporal differentiation experiments, behavior did not conform to Weber’s law. Instead, sensitivity decreased as time taken to complete the ratio increased.