Global and local dominance with concentric hierarchical stimuli and orientation classification task.

Prior studies have suggested the existence of global dominance for tasks involving decisions of stimuli orientation. This research used hierarchical stimuli, consisting of open-left and open-right semicircles, where participants had to indicate the direction of opening. The aim of this paper is to ascertain whether the opening size of the stimulus is a variable that modulates global dominance found in previous studies. In Experiment I and II, stimuli were presented having an opening of 25% and 10% of the total circle perimeter, respectively. The data show that global advantage depends on the opening size and attention conditions. The results can be explained according to the implications the opening size has on the classification of stimuli according to orientation.