Detection of the velocity of movement of visual stimuli by pigeons?

Researchers taught three pigeons to peck a key when dots on a screen moved.

If the dots stood still, pecking turned the food off.

The team slowly lowered the speed until the birds messed up.

They wanted the slowest motion the birds could still see.

The birds could spot movement as slow as 4–6 millimetres each second.

That is about the speed of a snail crawling.

When the same trial came late in a long run, the birds pecked more, showing a serial-position boost.

Coe et al. (1997) also saw serial-position effects, but with how often a colour showed up, not motion.

Both studies prove order in a session changes stimulus control, even when the cue is different.

Griffin et al. (1977) and Bacon-Prue et al. (1980) found memory for colour pairs drops after two seconds.

Hodos et al. (1976) did not test long delays, yet the shared decay curve hints motion memory fades the same way.

You now know motion cues can gain stimulus control at very slow speeds.

Use slow, steady hand or object movements when you want to draw attention during early discrimination drills.

Keep trials short or re-present the cue often, because control weakens as the session drags on, just like with colour or frequency cues.