Comparison of Avoidance Learning in Two Species of Lizards, Crotaphytus Collaris and Dipsosaurus Dorsalis
The performance of high and low substrate temperature groups of two species of lizards, collared lizards and desert iguanas, were compared on a shock-avoidance problem. All Ss made escapes on all trials of the three days of escape training. During Phase 1, no group of either species attained the criterion for avoidance learning within 250 trials. Phase 2 was conducted to analyze the failure to demonstrate avoidance learning. Half of all Ss were provided with a tunnel, as a more “natural” escape route. Half of all Ss were administered Reserpine in an attempt to reduce a postulated “freezing” response. The possibilities of habituation to shock were considered. Only the tunnel groups of collared lizards attained the criterion for avoidance learning. The performance of the tunnel group of desert iguanas improved significantly, but a significant interaction between the effects of the drug and tunnel treatments makes these results difficult to interpret. Procedural differences between this study and those conducted by Powell (1967, 1968) and Powell and Mantor (1969) are considered. Suggestions are made for future research with lizards.