Sensitivity to reinforcer duration in a self-control procedure.

Researchers used pigeons in a two-key setup. Pecking one key led to a short reinforcer right away. Pecking the other key led to a longer reinforcer after a delay.

The team then made both delays longer while keeping the same short-versus-long payoff. They watched whether the birds switched their pick.

When both sides made the birds wait longer, the pigeons flipped. They now chose the key that gave more food, even though the wait was still long.

The result shows that duration matters more when delays are already stretched out.

Reed et al. (1988) later saw the same flip in teens with severe ID. Longer equal delays pushed them toward the bigger later reward too.

Lane et al. (1984) looked at whether pigeons could change their mind mid-delay. Their birds sometimes pecked the useless key while waiting, hinting that earlier work may have overstated self-control.

Hansen et al. (1989) worked with kids and found delay sensitivity shows up only after grade-school age. Younger children tracked amount but not wait time, lining up with the pigeon data that duration cues gain power only when delays are already long.

When you teach waiting skills, first stretch the delay for both choices. A child is more likely to pick the bigger reward when the wait is long for every option. Use this setup before you fade the delay on the preferred side.