A clock not wound runs down.

@article{Killeen1999ACN,
  title={A clock not wound runs down.},
  author={Peter R Killeen and Scott S. Hall and Lewis A Bizo},
  journal={Behavioural processes},
  year={1999},
  volume={45 1-3},
  pages={129-39}
}
Seven pigeons were trained to respond on one key during the first half of a 60-s trial, and on another during the second half, to test the prediction that the rate of the internal pacemaker should slow in the absence of reward. The relative probability of responding was well-described by Erlang distributions, which yielded as parameters the period of the pacemaker and the criterial number of counts for switching to the second key. During a subsequent period of extinction the period increased… CONTINUE READING