Eye movement patterns during object recognition are modulated by perceptual expertise and level of stimulus classification.

摘要

In a previous study, Leek & Johnston (2008, Platform talk, Vision Science Society) showed that fixation patterns during three-dimensional object recognition show a preference for image regions containing local concave curvature minima at surface intersections. In this study we examined the extent to which fixation-based local shape analysis patterns are influenced by the perceptual expertise of the observer and the level of stimulus classification required by the task. The study was based on the paradigm developed by Wong, Palmeri & Gauthier (2009, Psychological Science, 20, 1108-1117.) in which observers are extensively trained to categorize sets of novel objects (Ziggerins) at either a basic or subordinate level of classification. The effects of training were measured by comparing performance between a pre- and post-test sequential shape matching task that required either basic- or subordinate-level judgements. In addition, we also recorded fixation patterns during the pre- and post-tests. Fixation data were analysed using the FROA methodology (Johnston & Leek, 2009, Journal of Eye Movement Research, 1 (3):5, 1-12). The results showed significant effects of training on shape matching RTs in the post-tests. In particular, Ss showed evidence of perceptual expertise at making basic and subordinate-level shape classification judgements. We also found that the acquisition of perceptual expertise resulted in changes in the local spatial distributions of fixational eye movement patterns observed in the pre- and post tests. This finding provides a clear link between fixation-based shape analysis patterns, perceptual expertise, and the level of shape classification being undertaken by the observer.