Lizard Ethology 
207 
Laboratory and Field Studies 
For contextual information and confirma- 
tion of the “naturalness” of behavior, field 
studies are valuable but present certain 
problems. Field conditions may vary con- 
siderably from area to area and from year 
to year, necessitating many years of ob- 
servation before an investigator might be 
confident that he has inventoried the com- 
plete range of behavior. Further, field studies 
may be prejudiced by the presence of the 
observer (Cowles and Bogert, 1944; Schne- 
irla, 1950), partly because the observer may 
be perceived as a potential predator (Edson 
and Gallup, 1972). 
Laboratory studies, on the other hand, 
generally rely on a specific behavior per- 
formed out of context by animals in an 
ecologically impoverished environment. De- 
privation of outlets for some activities may 
profoundly influence other behavioral pat- 
terns in unexpected ways (Hediger, 1955; 
Morris, 1964; Kavanau, 1964, 1967). For ex- 
ample, general activity may increase, de- 
pending upon the nature of the opportunities 
(Hinde, 1970). Compulsory regimes and the 
constraints of small habitats may also lead 
to distortions of behavior that cause con- 
tradictory or paradoxical results (Kavanau, 
1964, 1967). 
Giving the animal some control over its 
habitat or initiative in environmental manip- 
ulation may be illuminating in some respects, 
but there is the danger that the search 
for “good performers” or tractable animals 
may find only subjects that demonstrate 
principles peculiar to themselves (Breland 
and Breland, 1961). When an animal is re- 
quired to make arbitrary associations, the 
principles explicated may be peculiar to 
those associations and not necessarily appli- 
cable to the animal in nature (Morris, 1964; 
Seligman, 1970). 
Ideally, the experimental ethologist deal- 
ing with an unfamiliar species would have a 
thorough knowledge of the habitat in which 
the animal’s behavioral patterns were forged. 
Indeed, without such knowledge, Hediger 
points out, there may be contradictory im- 
pressions of the abilities of an animal (1950: 
84). Furthermore, without the intimate and 
continuing experience with a species that the 
development of an ethogram requires, there 
may be contradictory interpretations of func- 
tion (Hediger, 1955:140). 
Lorenz (1935, trans. 1970:111-112) has 
pointed out the difficulties of objective com- 
munication of “pure” observations as op- 
posed to experimental results. In a recent 
review of observational sampling methods, 
Altmann (1974) has contrasted internal and 
external validity, corresponding in each case 
to the consistency of laboratory research and 
the generalizability of field studies. A critical 
aspect of any experiment is the presence of 
controls. These, of course are not absent in 
the field, but are nonmanipulative. Accord- 
ing to Altmann, it is the observer’s sampling 
decision that influences the relative internal 
validity of the observations. 
According to Seligman (1970), the premise 
of equipotentiality that underlies much psy- 
chological investigation (general learning 
theory) is limited in its usefulness because of 
its emphasis on arbitrary associations, 
events, and its avoidance of “contamination” 
by an animal’s biology or experience (Selig- 
man and Hager, 1972). He proposes a “pre- 
paredness continuum” that is recognized, for 
example, by the ease with which an animal 
can make an association (acquisition). The 
point along the continuum at which an ani- 
mal functions in a given situation is sig- 
nificantly influenced by its evolutionary and 
developmental history. This suggests that a 
behavioral pattern readily demonstrated or 
easily elicited in the laboratory is a response 
that an animal is “prepared” to make, and 
that its causation and function are probably 
not significantly different from that found in 
nature (Jenssen, 1970a). As Hediger points 
out, however, a captive animal that is no 
longer subject to the constraints of its 
natural environment may behave in unpre- 
dictable, even unprecedented ways (Hediger, 
1950 :91). 
The ability of lizards to learn is attracting 
considerable attention (Brattstrom, this 
volume; Peterson, discussion). As Lorenz 
