Behavior and Neurology of Lizgrde 
N. Greenberg and P. D. MacLean, eds. 
NIMH, 1978. 
Learning Studies in Lizards 
Bayard H. Brattstrom 
Department of Biology 
California State University, Fullerton 
SUMMARY. Originally, learning studies on lizards were largely unsuccessful because workers 
either used unimportant cues and reinforcers or conducted tests at environmental temperatures 
too low for the lizards to become active. Recent studies have shown that learning in lizards is 
temperature dependent. With heat as a reinforcement, lizards quickly learn simple T-mazes, 
pattern discrimination, and wheel running. Given bursts of heat as reinforcement, lizards can 
easily learn to press a bar for additional heat. Studies have also demonstrated a lizard’s capacity 
for discriminating noxious prey, latent learning, discriminating color, and learning refinements 
in thermoregulation. 
INTRODUCTION 
Reptiles have generally been considered to 
have less complex behavior than other verte- 
brates. This view is attributable to the early 
behavioral studies that were carried out at 
ecologically unsuitable temperatures. Under 
those conditions some lizards required more 
than 300 trials to learn simple tasks (see 
review in Northcutt and Heath, 1971). In 
these studies, ambient or radiant heat was 
insufficient for reptiles to reach normal ef- 
ficient body temperatures. Such studies were 
really measuring the animal’s metabolic in- 
activity rather than learning ability (Bratt- 
strom, 1965, 1974). In 1968, Krekorian, 
Vance, and Richardson showed that learning 
in lizards is temperature dependent. 
Recognizing that lizards assume specific 
orientations and postures when basking 
(Brattstrom, 1965, 1971; Heath, 1965), I 
Note: Instead of presenting this paper at the sym- 
posium, I presented its conclusions and then did a 
simulation-game of creating a lizard and its behav- 
ioral, evolutionary, genetic, anatomical, and physi- 
ological components using the participants in the 
symposium to play “parts” of the lizard and its en- 
vironment. The task was to have the lizard awake, 
eat, escape from predators, and engage in aggres- 
sive behavior. The function of the players was to 
try to integrate their interactions. The main purpose 
of the game was to determine the complexity of the 
lizard, to recognize the portion of the lizard others 
were studying, and to increase the intellectual and 
social communication and interaction of the players. 
began a series of studies on their ability to 
learn in order to develop new techniques for 
studying social or thermoregulatory be- 
havior. About the same time, Vance and 
Richardson and their co-workers initiated a 
series of studies on learning in lizards using 
ecologically relevant cues and reinforcers to 
study brightness discrimination, temperature 
dependent learning, and reversal learning 
(Bicknell and Richardson, 1973; Garzanit 
and Richardson, 1974; Julian and Richard- 
son, 1968; Krekorian, Vance, and Richard- 
son, 1968; Richardson and Julian, 1974; 
Vance, Richardson, and Goodrich, 1965; and 
Peterson, MS). Burghardt (in press) has 
recently prepared an extensive review paper 
on learning in reptiles. I will mention here 
some of the key studies on learning and 
then describe some of the work done in my 
laboratory over the last 12 years that has 
not been previously reported. 
Turtles, caimans, and the tuatara have 
been used in studies on reversal, spatial, 
discrimination, maze, and probability learn- 
ing (Kirk and Bitterman, 1963, 1965; Wil- 
liams, 1967a, 1967&, and 1967c; Williams 
and Albiniak, 1972 ; Williams and Robertson, 
1970). Northcutt and Heath (1971, 1973) 
showed rapid learning in both caimans and 
tuataras using one-choice point T-maze with 
“return to home pen” as reinforcement. They 
173 
