Discrimination training, partial reinforcement, and increases in intertrial interval all reduce response speed in a continuously reinforced key-pecking task.

Researchers worked with pigeons in a small lab chamber.

Each bird pecked a lighted key for food on every trial.

The team then made three changes: longer pauses between trials, switching from every-peck-pays to only-some-pecks-pay, and adding a color cue that meant pay or no-pay.

They timed how fast the birds pecked after each change.

All three changes made the pigeons slow down.

Longer breaks between trials had the biggest effect.

When food no longer came after every peck, the birds acted like the task was less urgent.

Sponheim (1996) saw a twist: half the pigeons actually preferred the partial-pay schedule, but only when the key colors kept changing.

Once colors stayed the same, the preference vanished.

Together the two studies show that partial reinforcement can feel either boring or exciting — it depends on what else is happening in the room.

Sachs et al. (1969) add another layer: when pigeons shift from every-peck-pays to partial-pay, their pecks not only slow down but also land in looser, more variable spots.

The speed drop and the sloppy aim go hand-in-hand.

If you thin the schedule or stretch the inter-trial interval, expect the learner to pause more and respond more slowly.

Watch for the same pattern when you add discrimination cues.

To keep brisk responding, keep trials tight and reinforcement dense at first, then fade gradually while you monitor latency.