A Bayesian Approach to Analyzing Latency as Evidence for Learning, with Comments on Foraging Techniq

Liew, Amanda

Cooper, Taylor

School of Biological Sciences

Georgia Institute of Technology

Atlanta, GA USA

tcooper84@gatech.edu

Andrle, Gabriel

Department of Environmental Sciences

Emory University

Atlanta, GA USA

Mendelson, Joseph

School of Biological Sciences

Georgia Institute of Technology

Atlanta, GA USA

Department of Herpetology

Zoo Atlanta

Atlanta GA USA

Anecdotal observations and a few previous studies suggest that lizards may have strong cognitive skills, in part, perhaps, owing to behaviors such as optimal foraging and territoriality. We tested four lizard species in a longitudinal repeated-trials experimental design using a puzzle-feeder device to evaluate learning, in the form of latency trends over time, in three species of monitor lizard (Varanus spp.) and one species of beaded lizard (Heloderma sp). We used a Bayesian multilevel modeling statistical design and incorporated unsuccessful trials as censored data. Collectively, all lizard subjects showed a pattern of decreasing latencies over time. We interpret this pattern as learning among our lizards. Notable individual and inter-specific differences were evident, however, suggesting differing cognitive abilities among our sample. In this case, the monitor lizards exhibited steeper declines in latencies and greatly reduced variation in comparison to the beaded lizards. We found differential use of the claws versus the snout among the lizards, which is consistent with a previously posed hypothesis based on different species than we measured. This study expands on the paucity of studies of reptilian cognition.