Performance differences according to the concentration of saline solution used as reinforcer in the common toad (Bufo arenarum)

MARIANA G. IURMAN; RUBÉN N. MUZIO

Buenos Aires

Congreso; 14 th Biennial Scientific Meeting of the International Society for Comparative Psychology; 2008

International Society for Comparative Psychology

There is little information about appetitive and aversive animal learning using the same kind of stimuli dimension of the reinforcer. Based on previous data obtained in our laboratory, we present a study where toads (Bufo arenarum) were exposed to several concentrations of NaCl solutions used as reinforcers (from appetitive to aversive conditions) in a runway procedure. Three groups of toads, partially dehydrated, were trained in a runway situation: Appetitive (deionized water as reinforcer, where animals gain weight), Aversive (800mM NaCl solution, where animals lose weight), and Neutral (300mM NaCl solution, where animals neither gain nor lose weight). Running latency and weight before and after each trial were measured. Results showed a typical decrement of running latency in the group Appetitive. In contrast, group Aversive always showed maximum latency after the second trial. Group Neutral showed high latencies, and not differ significantly from group Aversive. These results correlate with data of weight variation: group Appetitive gained an average of 0.7g/100g, group Aversive lost an average of 0.3 g/100g, and group Neutral not gained or lost weight (average -0.01g/100g). Thus, these results show that this situation could be suitable for a comparative study on the neurobiology of appetitive and aversive learning.