Understanding the structural determinants of object confusion in memory: An assessment of psychophysical approaches to estimating visual similarity

Geneviève Desmarais, & Mike J Dixon. (2005). Understanding the structural determinants of object confusion in memory: An assessment of psychophysical approaches to estimating visual similarity. Perception and Psychophysics, 67(6), 980-96.  Retrieved September 11, 2011, from ProQuest Social Science Journals.

    I chose this article because I thought the topic of visual agnosia was very interesting and I wanted to learn more about what people who have this disorder go though. I also wanted to know what kinds of treatments or tests are needed to diagnose visual agnosia.
    Computer generated images that differ in dimensions like thickness , tapering , curvature  have been used to help find deficits in visual agnosia.To determine distance in psychophysical shape space , two different scaling methods were used to develop sets of shapes. An objective method based on visual search, and a subjective method based on judgments of similarity and there was also a third method that did not use scaling. Each method of psychophysical shape space was estimated and then assessed by measuring the confusions within memory among the shapes. The results of this study suggested that although neither of the methods perfectly reflected psychophysical shape space, but subjective scaling was a better estimator of distance in psychophysical space shape than were other approaches. The results also found that the number of confusions produced on each set of shapes was used to develop a new set of shapes that accurately estimated distance in psychophysical shape space. The results suggest that a combination of approaches is desired in order to accurately estimate distance in psychophysical shape space.