Figure 1.

Examples of fixation ‘bug’ stimulus and texture surfaces. (a) The fixation bug's thorax, abdomen and four diagonal legs were presented to the dominant eye. (b) The head and remaining bug parts were presented to the non-dominant eye. When fused, a complete bug with six legs and a pair of antennae would be perceived. Note that figure 1a,b included here are for illustrative purposes only and were not designed as a stereo pair. (c) Tiled texture background and (d) random dot background. For tiled backgrounds rendered stereoscopically, the monocular cues to surface slant stem from distortions of the regular grid pattern mapped onto the surface, and the disparity signal to surface slant stems from the differences between right and left eyes' retinal images. Examples of trial feedback are also depicted here. The dichoptic bug crawls away (c) for an incorrect response and (d) it explodes in little bits for a correct response. (Online version in colour.)