risk sensitive foraging by rats in the operant arena
abstract
the operant arena was used as the framework in
which to study the theory of risk-sensitivity, a small
colony of hooded rats was exposed to increasing work
demands while given the choice between simultaneous
fixed ratio (risk-averse) and variable ratio (riskprone)
schedules.
the four rats were maintained in a large arena
with access to eight feeding stations for two 30-minute
sessions per day. stations on one side of the arena
were programmed to pay off on a fixed ratio, while
those on the other side paid off on a variable ratio.
the subjects were exposed to ratio value schedules 5,
10, 2 0, 40, and 80 in an ascending sequential order;
each schedule was in effect for seven consecutive days.
dispersion patterns, transition types, reinforcements,
and the observed preference for working on the
fr or vr side of the arena were studied. throughout
the experiment the rats showed an overwhelming preference
for the fr side of the arena. however, there
was a gradual decrease in the magnitude of the preference
for the fr side of the arena over the course
of the experiment. it is therefore concluded that as
the cost of food increased rats became more risk-prone
in their foraging preference. it is also suggested
that had the animals been allowed to experience a
negative net energy budget (i.e., starvation) a more
powerful effect would have emerged.
collections
- retrospective theses [1604]