| dc.description.abstract | A group consisting of eight male Hooded rats was tested for
risk-sensitive foraging preferences in an eight station
operant arena, under conditions of open and closed economies.
The group could choose to forage at either four fixed
interval stations or four variable interval stations of the
same mean interval value. The visual, tactile, and spatial
discriminative stimuli associated with the fixed and variable
stations was enhanced to assist in discriminating between the
variances of the schedules associated with the stations. The
following four interval values were tested, with each in
effect for five consecutive days: 15, 30, 90, and 180
seconds. The open economy was defined by a 30 minute session
conducted twice a day followed by a supplemental feeding at
the end of each day. The closed economy consisted of
continuous 2 4 hour access to the stations, with no
supplemental feeding. Results revealed differential effects
upon foraging choices by the two different economies. In the
open economy, the group of rats were risk-indifferent in
their foraging preferences, while in the closed economy the
rats foraged in a manner that was contrary to risk-sensitive
theory. During the closed economy the rats were risk-prone
when net energetic gain was high and became less risk-prone
as net energetic deficits occurred. Discussion is given on
the possible influence of competition and discriminatory cues upon a rat populations foraging preferences. | |
