Choice between rewards differing in amount and delay: Toward a choice model of self control.
Real seconds, not just ratios, steer choice—so program delays in actual time.
01Research in Context
What this study did
The team set up a two-key pigeon chamber. Pecking one key gave a small food pellet right away. Pecking the other key gave six pellets after a delay.
They kept the pellet ratio at 6:1 and tested three delay ratios: 6:1, 3:1, and 3:2. Then they stretched the absolute wait times while holding the ratios still.
The goal was to see if choice stayed the same when only the real seconds changed, not the proportion.
What they found
At the 6:1 and 3:1 ratios, birds switched to the tiny immediate pellet more often as the real seconds grew longer.
Surprise came at the 3:2 ratio: longer waits made the birds pick the big delayed pile more, not less.
Static ratio models predicted no change; the birds proved them wrong.
How this fits with other research
Haemmerlie (1983) ran the same three ratios with pigeons and got the same flip—an almost perfect direct replication.
Skrtic et al. (1982) worked with rats and equal delays. They saw preference for the bigger reward rise as delays lengthened, matching the 3:2 result here.
Hamilton et al. (1978) showed you can train patience by slowly fading in the wait. That lines up: absolute seconds matter more than the math on paper.
Why it matters
When you write a token board, DRO, or self-control program, think in real seconds, not just ratios. A 2:1 wait ratio feels different at 10 s vs 60 s. If you want a learner to hold out for the big reinforcer, keep the early delays short in real time, then stretch slowly.
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02At a glance
03Original abstract
A concurrent-chain procedure was used to study pigeons' choices between rewards differing in both amount and delay. The shorter delay terminated with a 2-second access to grain whereas the longer delay terminated with a 6-second access to grain. The ratio of the delays was constant within a given condition while their absolute values were varied. Over conditions, ratios of 6:1, 3:1, and 3:2 were studied. As the absolute values of the delays to reinforcement increased, preference for the longer-delayed but larger reward decreased under both the 6:1 and 3:1 ratios, but increased under the 3:2 ratio. These results are inconsistent with choice models predicting no change in preference when the ratios of delays and amounts are held constant. In addition, the change in preference under the 3:1 ratio is inconsistent with a simple multiplicative interaction of the trade off between reinforcer amount and delay, and suggests that delay is a more potent determinant of choice than is amount. These results have implications for models that view choice between small immediate rewards and large but delayed rewards as underlying the behavior commonly called self control.
Journal of the experimental analysis of behavior, 1980 · doi:10.1901/jeab.1980.34-135