Control of key pecking by the duration of a visual stimulus.

Scientists taught pigeons to tell short lights from long lights.

Birds pecked one key if the light lasted a little time. They pecked a different key if it lasted longer.

The team also tried a one-key method. Same birds, same lights, just one key to peck.

Both ways worked. Birds learned short vs long.

The two-key way made the split sharper. Birds switched around 7–8 seconds. With one key the switch was fuzzier near 10 seconds.

Stolz (1977) later showed long pecks get punished while short pecks keep going. That backs up the idea that peck length is a real, separate behavior.

Stancliffe et al. (2007) mixed timing with memory cues. At first the birds struggled, but after lots of trials they acted like pure timers again. It shows timing stays strong even when the task grows.

Reynolds (1966) had already proved pigeons can feel time differences. The 1974 paper moves that work forward by using the difference to steer choices.

If you need a client to judge short vs long events, give two clear choices. Two response options make the line between “short” and “long” stand out. Use one response only when you want a gentle fade.