Performance is often impaired linearly with increasing angular disparity between two objects in tasks that measure mental rotation or object recognition. But increased angular disparity is often accompanied by changes in the similarity between views of an object, confounding the impact of the two factors in these tasks. We examined separately the effects of angular disparity and image similarity on handedness (to test mental rotation) and identity (to test object recognition) judgments with 3-D novel objects. When similarity was approximately equated, an effect of angular disparity was only found for handedness but not identity judgments. With a fixed angular disparity, performance was better for similar than dissimilar image pairs in both tasks, with a larger effect for identity than handedness judgments. Our results suggest that mental rotation involves mental transformation procedures that depend on angular disparity, but that object recognition is predominately dependent on the similarity of image features.
Bibliographical noteFunding Information:
This work was supported by Grants from the Hong Kong Research Grants Council (project Nos. HKU 4260/03H and HKU 7649/06H), the Temporal Dynamics of Learning Center (NSF Science of Learning Center SBE-0542013) and the James S. McDonnell Foundation.
- Mental rotation
- Object recognition
- Viewpoint effects
- Visual similarity