A clock not wound runs down.

Area of Science:

• Behavioral neuroscience
• Animal cognition
• Psychology of timing

Background:

• Understanding the internal mechanisms of timing is crucial for explaining animal behavior.
• Previous models have not fully accounted for pacemaker adjustments in non-rewarded periods.

Purpose of the Study:

• To investigate if the internal pacemaker's rate changes in the absence of reward.
• To test the predictive power of the Behavioral Theory of timing against other models.

Main Methods:

• Seven pigeons were trained on a two-key task within a 60-second trial.
• Erlang distributions were used to model response probability and extract timing parameters.
• Extinction periods were introduced to observe changes in pacemaker behavior.

Main Results:

• Pigeon responding patterns were accurately described by Erlang distributions.
• The pacemaker period (time) increased linearly during extinction.
• The criterial count (number of responses) for key switching decreased over time.

Conclusions:

• The internal pacemaker's rate slows down when reward is absent.
• Behavioral Theory of timing accurately predicts this pacemaker slowing.
• Findings support the Behavioral Theory of timing over alternative models.