Abstract
In previous cue recruitment experiments, subjects learned to use a novel cue to disambiguate the direction of rotation of a bistable Necker cube (Haijiang et al. 2006, Backus and Haijiang 2007). In these studies, trusted cues (occlusion and retinal disparity) were paired with a new position cue. We asked whether subjects with different levels of stereo acuity- thus presumably with different capacities for using our binocular disparity cue- would learn the new cue equally well. All subjects (n = 42) were tested on four different stereo acuity measures: the TNO test, the Paul Harris Randot test, the TODES test, and an in-house anaglyph display. Subjects also self-reported their ability to see Magic Eye (R) stereograms. During the experiment, subjects indicated which way a wireframe Necker cube was rotating on 400 trials, with alternating training and test (ambiguous) trials. Stereo ability correlated across subjects with proportion of training trials seen as specified by disparity (r = −0.72, p [[lt]].001). Performance on test trials was also well correlated with stereo ability (r = −0.41, p = .01 ). Better performance on test trials seems to result from the ability to see more training trials correctly: training trial and test trial performance was highly correlated (r = 0.59, p [[lt]].001). Three subjects were removed from the analysis as outliers. These subjects had poor stereo ability (ave = 550 sec arc), but were able to learn the new correlation as well as those with stereo acuities as low as 30 sec arc. We speculated that these subjects were using the occlusion cue to learn the correlation even in the absence of stereo information. However with a modified version of the first experiment, we found that these subjects were using the disparity information to make their perceptual decisions. For these participants, static stereo ability may not indicate stereo ability when a stimulus is moving.