Effects of occasional short interfood intervals on temporal control in pigeons

This study explored pigeon memory for short time intervals. Occasional (one per session) shorter-than-usual interfood intervals (IFIs) were interspers ed in series of longer IFIs. In phase 1, the shorter IFIs were of a magnitu de that varied from daily session to session. In phase 2, the shorter IFIs were of one magnitude for 20 consecutive daily sessions. Analysis of the re sults of both experiments showed that pigeons' memory for an IFI was not re stricted to the immediately preceding interval but rather decayed exponenti ally with a half-life of around three intervals. This effect did not take t ime to develop and did not change over the course of training. These result s have implications for the memory component of both clock and non-clock-ba sed theories of animal timing. (C) 1999 Elsevier Science B.V. All rights re served.