Widholm, J. J., Silberberg, A., Hursh, S. R., Imam, A. A., & Warren-Boulton, F. R. (2001).
Stock optimizing in choice when a token deposit is the operant.
Journal of the Experimental Analysis of Behavior,
76, 245-263.
Each of 2 monkeys typically earned their daily food ration by
depositing tokens in one of two slots. Tokens deposited in one
slot dropped into a bin where they were kept (token kept).
Deposits to a second slot dropped into a bin where they could be
obtained again (token returned). In Experiment 1, a fixed-ratio
(FR) 5 schedule that provided two food pellets was associated
with each slot. Both monkeys preferred the token-returned slot.
In Experiment 2, both subjects chose between unequal FR schedules
with the token-returned slot always associated with the leaner
schedule. When the FRs were 2 versus 3 and 2 versus 6,
preferences were maintained for the token-returned slot; however,
when the ratios were 2 versus 12, preference shifted to the
token-kept slot. In Experiment 3, both monkeys chose between
equal-valued concurrent variable-interval variable-interval
schedules. Both monkeys preferred the slot that returned tokens.
In Experiment 4, both monkeys chose between FRs that typically
differed in size by a factor of 10. Both monkeys preferred the
FR schedule that provided more food per trial. These
data show that monkeys will choose so as to increase the number
of reinforcers earned (stock optimizing) even when this
preference reduces the rate of reinforcement (all reinforcers
divided by session time).
Key words: maximizing, behavioral economics, choice, food, token
deposit, monkeys