MNEMONICS FOR VARIABILITY - REMEMBERING FOOD DELAY

Three experiments with White Carneaux pigeons (Columba livia) investig ated memory and decision processes under fixed and variable reinforcem ent intervals. Response rate was measured during the unreinforced tria ls in the discrete-trial peak procedure in which reinforced trials wer e mixed with long unreinforced trials. Two decision models differing i n assumptions about memory constraints are reviewed. In the complete-m emory model (J. Gibbon, R. M. Church, S. Fairhurst, & A. Kacelnik, 198 8), all interreinforcement intervals were remembered, whereas in the m inimax model (D. Brunner, A. Kacelnik, & J. Gibbon, 1996), only estima tes of the shortest and longest possible reinforcement times were reme mbered. Both models accommodated some features of response rate as a f unction of trial time, but only the second was compatible with the obs erved cessation of responding.