Which is an example of stimulus shape transformation?

• A. Taking a line drawing of a bed and slowly changing it into the letters b-e-d to help a child learn to read the word bed.
• B. A line drawing of a bed that remains the same.
• C. A photograph of a bed assembled from many small shapes while maintaining its overall shape.
• D. A bed silhouette that is colored differently.

Answer: (A)

Stimulus shape transformation means changing the physical form of a stimulus into another form that still cues the same thing. In this example, morphing a line drawing of a bed into the letters b-e-d changes the shape of the stimulus while linking it to the same concept—the word for the object. This gradual transformation helps a learner connect the picture to the written word by showing how the same idea can appear in different shapes.

The other scenarios don’t involve transforming the shape: keeping the line drawing unchanged isn’t a transformation; assembling the bed from many shapes preserves the overall form without morphing it into a new representation; changing color alters perceptual features but not the shape itself. Thus, turning the drawing into the letters demonstrates stimulus shape transformation most clearly.