Memory for sequences of stimuli and responses.

Bacon-Prue et al. (1980) taught pigeons two-step sequences. The birds saw two colors in order. They had to peck the matching keys in the same order.

After learning, the team waited 0.5, 2, or 4 seconds before testing. They counted how many sequences the birds still got right.

At 0.5 seconds the pigeons scored about 90 percent. At 2 seconds scores fell to 70 percent. By 4 seconds they were near chance.

Memory for the short chain faded fast. A two-second gap was enough to lose control.

Duker et al. (1991) ran a follow-up pigeon study. They showed stimulus-choice gaps hurt more than choice-reinforcer gaps. Both papers agree: keep the delay between cue and response short.

Diaz-Salvat et al. (2020) worked with children. They found response order did not matter for resurgence; response number did. The bird data say order is forgotten quickly, yet the child data say order is less important than having many options. Together they hint: teach several responses fast, then review soon.

Fontes et al. (2018) and Sullivan et al. (2020) showed that when one old response comes back, others tag along. Bacon-Prue et al. (1980) explains why: after a few seconds the whole sequence is already slipping away, so any piece can resurface.

When you chain skills, insert the prompt or probe right away. Wait more than two seconds and the learner may forget the order. Quick turns keep the sequence intact and cut resurgence later.