abstract
- Observers made speeded discriminations of whole, occluded, and mosaic shapes. Shape matching times increased with the amount of occluded shape (Experiment 1), as did the time to merely discriminate 2 shapes (Experiments 2-4). By contrast, the time to judge the shape of the visible portion decreased with larger occluded regions (Experiments 5-7). Experiments 3 and 6 used motion parallax to show that different perceptual operations are involved in discriminating occluded versus mosaic shapes. Experiments 4 and 7 showed that shape completion was unaffected by spatial attention. Results suggest that shape completion is a rapid and obligatory aspect of perception. However, they also show that the time course of completion varies with the size of the hidden region.