Stimulus properties of conspecific behavior.

The team placed two pigeons side by side. One bird worked on a multiple schedule that produced a clear pattern of pecks and pauses. The other bird could only watch.

Next, the observer bird had to learn a new discrimination. Some trials showed the partner’s schedule-correlated movements. Other trials showed color lights. The bird had to peck left or right depending on which cue appeared.

Reversal tests and blackout checks made sure the observer was controlled by the partner’s behavior, not by food smells or cage sounds.

The observer pigeons quickly learned to use the partner’s schedule-correlated movements as a signal. They chose the correct side almost every time.

When the cue meaning was flipped, the birds reversed their choices just as fast. The living bird had become a living discriminative stimulus.

Blackman (1970) already showed that pigeons can follow color lights linked to fixed-interval schedules. Millard (1979) moves the light inside the partner’s body; the schedule now glows through behavior instead of a bulb.

Shamlian et al. (2016) took the same multiple-schedule logic and taught a child with ASD to mand only when the right picture was present. The bird work gave the basic blueprint; the therapy team added words and cookies.

Mansell et al. (2002) faced the opposite problem—learners with severe ID who could not tell pictures apart. They added a 5-second delay before the correct picture appeared. Both studies hunt for tricks that sharpen stimulus control, one with delay, one with a living cue.

If another animal’s movements can function as an SD, then social cues in your classroom already have power. Watch for the moment a peer starts hand-flapping or settles to work; that moment can become a signal for the learner beside them. Try pairing a brief peer model with your trial cue, then fade the extra prompt. You may get stimulus control for free.