Kontur ve konfigürasyonun görsel kalabalık üzerindeki etkisi

Visual crowding refers to poor target identification performance due to the presence of flankers. Even though crowding studies mostly presented for low level stimulus settings, it is observed in high level settings as well such as faces and configuration. This study is aimed to investigate the effect of contour type (sharp-edged vs curve-edged) and configuration type (random vs smooth) with two experiments in crowded scenes. We hypothesized that the sharp-edged contours should be reacted faster for and more accurately compared to the curve-edged ones due to assumption of hierarchical and pooling models. According to both models, objects are recognized in a hierarchical way such that low-level and high-level features are orderly processed in the cortex. Sharp-edged contours might have an identification advantage due to comprising simple lines and intersections whereas circle does not have obvious components as the triangle has. We also expected that random configuration trials to have better outcome rates compared to regular and irregular ones because grouping can make detection of the target harder due to the similarity between target and flankers. We performed two experiments where we controlled configuration and contour respectively. We compared reaction times (ms) and accuracy rates (percentage) as outcome variables. Results of the first experiment have confirmed the hypothesis that the advantage of sharp-edged contour was obtained from both the accuracy and reaction time analysis. Also, random configurations were responded more accurately, as we had expected. However, main effect of configuration was not reflected on the reaction times. The second experiment was motivated to find the impact of high-level stimulus features by adding an incongruent contour type to smooth and regular configurations. Our results indicated the advantage of sharp-edged contours and random configurations in crowded scenes for identification performance.