Attention expands visual space
43.4072, Monday, 18-May, 8:30 am - 12:30 pm, Pavilion
Liu Zhou1, Teng Leng Ooi2, Zijiang He3; 1Key Laboratory of Brain Functional Genomics, School of Psychology and Cognitive Science, East China Normal University, China, 2College of Optometry, Ohio State University, 3Dept. Psychological and Brain Sciences, University of Louisville
Whereas much is known about attention’s role in object perception, little is known of whether attention affects the representation of the visual space. Here, we asked if a differential allocation of attention resource to either the lower visual field (ground) or upper visual field (ceiling) affects space perception. In Experiment 1, the observer fixated on a small, dimly lit LED (1.5m at the eye level) for 3-6 sec in a dark room. To ensure proper fixation, the LED was randomly turned off for 0.1 sec 1-3 times within a 3-6 sec fixation period. The observer had to correctly report each time the LED flickered. Meantime, he/she also attended to either the upper or lower field. Upon fixation removal, a texture surface (2x4 LED array spanning 1.4x3m area) was presented in either the upper or lower field (0.15 sec), followed by an LED target (1 sec) on the texture surface. The observer judged the target location using the blind walking-gesturing task. We found that when the target and texture surface were in the lower field, judged location was more accurate if the observer had attended to the lower field (cue-valid) rather than the upper field (cue-invalid). This indicates attention leads to less space compression in the attended field. Experiment 2 employed the same procedures except the target was located at the eye-level and the texture surfaces were presented in both the upper and lower fields. We found that judged target location was more accurate when the observer attended to the lower than upper field. This indicates the visual space is more extensive when one attends to the ground. Overall, our findings reveal that attention contributes to visual space representation, which perhaps is the first step in a cascade of operations leading to our perception of the visual world.