An assessment of horse (Equus ferus caballus) responding on fixed interval schedules of reinforcement: An individual analysis

• Fixed interval and peak procedure with sixteen horses.
• Assessed individual and pooled group performances.
• Analyzed six operationalisms of temporal control.
• Individual subjects’ responses demonstrated clear evidence of temporal control.
• Peak procedure produced inconsistent evidence of temporal control.

We assessed different measures of temporal control of horse (N = 16) responding on fixed interval schedules of reinforcement and a peak procedure. Subjects were trained to insert their heads into a response hoop to break an infrared beam in order to receive horse treats from an automatic feeder. We analyzed cumulative response records, binned response levels, quarter life, latency to first response, breakpoint, and inter-response patterns of the fixed interval trials. To analyze the peak procedure trials, we performed a series of bin analyses. To avoid potential pitfalls associated with aggregate analyses, we performed individual trial and subject analyses using an ordinal analysis within Observation Oriented Modeling. Most subjects produced clear indications that responding came under temporal control of the fixed interval schedules for most of our investigated measures, and some subjects’ response levels peaked at half of the peak trial intervals. We provide the first quantitative evidence of equine timing performances using protocols based on fixed interval schedules of reinforcement.