Function of intertrial interval in matching-to-sample.

Macdonald et al. (1973) worked with pigeons in a matching-to-sample task.

Birds had to pick the comparison key that looked like the sample key.

The team varied the pause between trials from 0 to 20 seconds.

When the pause was 0 seconds, the birds never learned the task.

A 5-second pause was enough for the birds to start choosing correctly.

Longer pauses up to 20 seconds kept the learning steady.

Webb et al. (1999) ran a conceptual replication with choice tasks.

They also saw that longer pauses changed how the birds responded, showing the effect holds across different setups.

Tavassoli et al. (2012) extended the idea to children.

They slowly stretched the pause between teaching trials and the kids learned social skills that lasted.

Vukelich et al. (1971) used monkeys and matched samples too.

They kept the delay dark and got good accuracy, showing timing details matter across species.

If you run discrete trial training, do not fire trials back-to-back.

Insert at least a 3–5 second pause so the learner can process the last answer.

Start short, then stretch the pause as skills grow.

This tiny shift can unblock acquisition for kids who seem stuck.