Stimulus control acquired by components of two color-form compound stimuli.

Researchers worked with pigeons in a lab. They showed the birds compound stimuli made of color plus shape.

Then they split the compounds apart. They wanted to see which part - the color or the shape - would control the pigeons' pecking.

Color won. When the color and shape were separated, the pigeons kept pecking based on color alone.

The shape part had almost no control over their behavior. Color overshadowed form completely.

Johnson et al. (1968) showed that prior training makes individual stimulus parts stronger. G et al. built on this by asking which part becomes strongest in color-form mixes.

Pisacreta (1982) later confirmed color and form stay dominant even when targets move every half-second. This extends G et al.'s finding to dynamic situations.

Henson et al. (1979) found that compact arrays speed up learning, but distinctive elements control later performance. This matches G et al.'s point that not all stimulus parts control behavior equally.

When you teach conditional discriminations, check what actually controls respondinga responding. If you use color-plus-shape cards, probe each dimension separately. The learner might be attending to color while ignoring the shape you think you're teaching.