Random and fixed two-trial sequences of reward magnitudes

Abstract

Albino rats were trained in a straight runway for 110 days, two trials/day, with an intertrial interval of 3-5 min. One trial each day ended in large reward (10 standard Noyes pellets for one group, 1 ml of 30% sucrose solution for another) and the other trial ended with small reward (1 pellet or 3% sucrose). The daily sequence of reward magnitudes, either small-large (SL) or large-small (LS), was determined by pseudorandom orders, so that a block of 8 days contained 4 SL and 4 LS days. For 20 days following this random-sequence training, all rats received fixed sequences, always SL or always LS, with the same reward type (standard pellets or sucrose solutions) as that used during random-sequence training. Differential running for different reward magnitudes (patterning) did not develop during random-sequence ttaining with either reward type. The fixed-sequence training generated patterning on Trial 2 but not on Trial 1. The data are discussed in the light of several possible sources of the stimulus control of patterning, and implications of the data for a sequential account of the successive negative contrast effect are briefly considered.

Odor-based runway performance as a function of deprivation state, squad size, and subject-rotation procedures

“…To avoid possible confounding due to reinforcer differences , all animals were administered the same type of reinforcer, a sucrose-water solution. The choice of this reinforcer was prompted by its previous use (Burns, DeHart , McRae, 1980 ;Burns, Dupree, & Lorig, 1978) with food-deprived animals.…”

Three-trial sequences of reward magnitudes with odor cues maximized

“…One alternative is the differential reinforcement of specific trial stimuli, stimulus events that are different from trial to trial but that are not generated by reward per se (Burns, DeHart, & McRae, 1980). A second possibility is conceptual rule learning: The animal learns something about the reward sequence as a whole and fits it into some sort of cognitive rule, "greater than" or "less than," for example (Hulse This research was supported, in part, by a grant from the Charles L. Mix Memorial Foundation through the Department of Psychology of Georgia Southwestern College to the first author and a grant from the Research and Creativity Committee of Emporia State University to the third author.…”