| Budget Amount *help |
¥1,800,000 (Direct Cost: ¥1,800,000)
Fiscal Year 1988: ¥300,000 (Direct Cost: ¥300,000)
Fiscal Year 1987: ¥1,500,000 (Direct Cost: ¥1,500,000)
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| Research Abstract |
The present study investigated some aspects of foraging decisions that a predator may make, such as how and where to feed by using a concurrent and successive choice procedure. In a concurrent choice procedure, the accessibility of the terminal links differed in the reinfrcer amount was varied by changing the duration of the initial link. Changing accessibility of the preferred outcome (the larger reinforcer) had a greater effect on choice than changing accessibility of the less preferred outcome (the smaller reinforcer). This finding is consistent with the prediction from Fantino's delay-reduction model. In a successive choice procedure, the effects of prey distribution on the patch-use strategy used by a pre dator were examined for three different types of the prey distribution, such as a Poisson, Binomial, and Negative binomial distribution. For all three distributions, the number of obtained preys increased with the increases in the search time, and also the duration of the give-up time, defined by the interval between the time the last prey was captured and the time the predator left the patch, increased with the increases in the search time. In this case, Herrnstein's matching model was successfully applicable to these data. These findings indicate that the psychological mechanisms assumed by the choice models play a role in making foraging decisions.
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