Utilization of odor cues as a function of reward-magnitude contrast and delay of reinforcement.

An experiment manipulating both reward-magnitude contrast and delay of reinforcement is reported. The results indicated that odor cues are produced under conditions of delayed large-reward versus nonreward contrast but not under large- versus small-reward contrast. Additional magnitude and delay manipulations that resulted in the elimination of odor-based double-alternation patterning in the straight runway are presented.