Stimulus control in the use of landmarks by pigeons in a touch-screen task.

Lowe et al. (1995) watched pigeons hunt for food on a touch screen. The screen showed a square frame and a small landmark dot. The birds had to peck the spot where the food should be.

Each bird got the same picture, but the team moved the landmark around. They wanted to see if the pigeons used the dot, the frame edges, or both to pick the spot.

Most pigeons followed the landmark dot. One bird ignored the dot and used only the frame edges. A few birds checked both cues and switched between them.

The study shows that even simple spatial tasks can give different stimulus control for each subject.

Rasing et al. (1992) found that pigeons switch from pecking a signal to pecking the food site as the gap between cue and food grows. Lowe et al. (1995) used a fixed gap and still saw individual choice of cue, showing that distance is not the whole story.

Mueller et al. (2000) later trained birds in many sample spots so the birds would look at the picture, not the place. Their success supports the idea that you must test across layouts to be sure the right feature controls the response.

GOLLUMIGLER (1964) showed that just changing the light that marks a schedule can change response rate. Lowe et al. (1995) extend this point to spatial cues: the same layout can control different birds in different ways.

When you set up a discrimination task, do not assume every client will use the cue you point out. Probe with slight moves of the stimulus or add extra cues, then watch which one the learner follows. If you see control by the wrong feature, train in many positions or add error-correction trials until the target feature drives the response.