Abstract
Very little is known about rapid categorization of materials in comparison with objects and scenes. In the conditions used by Sharan et al. (VSS 2011), material categorization is fast, but slower than object categorization. Here, we studied the effect of viewing condition on the reaction time (RT) of material and object categorizations using photographs of real-world objects. Stimuli included photographs of 30 gloves (15 leather; 15 fabric) and 30 handbags (15 leather; 15 fabric). Two viewing conditions were used: a “Full” view showing the whole object and a “Zoomed-in” view showing part of the object. For each viewing condition, two sets of 2AFC task on either material or object categorization were performed by two groups of observers, and their reaction time was measured. A color discrimination task (red versus blue circles) was used as baseline. For the “Full” images, observers were faster at the object task (Baseline Corrected RT = 73 ms) than the material task (Baseline Corrected RT = 85 ms). For the “Zoomed-in” images, observers were faster at the material task (Baseline Corrected RT = 75 ms) than the object task (Baseline Corrected RT = 97 ms). The results show that the speed of material and object categorization depends on the viewing condition.