Abstract
Despite continuous retinal chaos, we perceive the world as stable and complete. This illusion of stability is evoked over consecutive glances via redundancies in higher-order statistical information inherent in the visual environment. For instance, prior work has shown that repeating the average size of a set of differently sized circles over consecutive trials yielded faster reaction times in complex search tasks, compared to similar trials in which mean size was not repeated. In the current work, we elaborate on these findings, proposing that the main effect of visual stability on search times is attentional in nature. Observers conducted a difficult conjunction search task in which a tilted Gabor with a pre-defined spatial frequency had to be detected among a number of elements. Crucially, the mean size of the set of Gabors could either be kept constant over a series of trials, or changed on each trial. Importantly, regardless of the build-up of stability, individual elements changed on every trial. To investigate the involvement of attention, the number of elements (set size) could vary from trial-to-trial. Results show that search is strongly facilitated by visual stability, with faster response times for stable trials compared to unstable trials, such that 1) The effect of stability is independent of, and transfers over displays with different set sizes, 2) Faster response times benefit more from stability compared to slow response times, 3) A minimum number of repetitions is required to find a robust stability effect. Results of these experiments are discussed in terms of attentional capacity and change detection mechanisms.
Meeting abstract presented at VSS 2018