Biasing the pacemaker in the behavioral theory of timing

Area of Science:

• Behavioral Psychology
• Cognitive Science
• Neuroscience

Background:

• The behavioral theory of timing posits that the pacemaker rate, a fundamental component of internal timing mechanisms, is primarily determined by the overall rate of reinforcement.
• However, the potential influence of differential reinforcement rates on the pacemaker period, the inverse of pacemaker rate, remains less understood.

Purpose of the Study:

• To investigate whether the pacemaker period is sensitive to the differential rate of reinforcement within a trial.
• To examine how variations in relative reinforcer rates affect estimates of pacemaker period.

Main Methods:

• A two-alternative free-operant psychophysical procedure was utilized.
• Differential variable-interval schedules of reinforcement were applied to the first and second halves of a 50-s trial, with reinforcement contingencies systematically manipulated.
• Estimates of pacemaker period were derived by fitting a theoretical function to right-key response proportions across 5-s bins.

Main Results:

• Pacemaker period estimates were shortest when the differential reinforcer rate most strongly favored right-key responses.
• Conversely, pacemaker period estimates were longest when the differential reinforcer rate most strongly favored left-key responses.
• These findings indicate a direct relationship between relative reinforcer rate and pacemaker period.

Conclusions:

• The study provides evidence that the pacemaker rate, and consequently the pacemaker period, is influenced by the relative rate of reinforcement.
• This suggests that internal timing mechanisms dynamically adjust based on the perceived value or likelihood of reinforcement.