How fixation durations are related to the functional visual field and attentional guidance
Final Report Abstract
In the project “How fixation durations are related to the functional visual field and attentional guidance” it was tested whether fixation durations in visual search experiments vary in a meaningful manner. It could be shown that the average trial fixation durations mediates the effects of target-distractor similarity, stimulus density (i.e. crowding) and distractor heterogeneity on search time. Crucially, individual fixation durations in a trial could be used to estimate the size of the FVF. The FVF estimation on the basis of fixation durations leads to similar results as the estimation by the traditional gaze contingent moving window paradigm. However, the fixation duration approach comes with less experimental effort and can be applied in a post-hoc manner in eye-tracked free viewing search experiments. Thus, the present project established a model for the estimation of the FVF that can be applied in future visual search studies in order to report a universal measure of the experiments’ search difficulty. Reporting the FVF allows for better comparability between studies. Furthermore, the FVF may help to explain why important targets are sometimes missed even though the observer had fixated close to it. The experimental results show that the fixation duration approach can be applied both in search through artificial stimuli and in search through realistic scenes. For scene search, the results suggest that the fixation duration approach reveals when observers tend to rely more on scene guidance and when they tend to rely more on target feature guidance. Overall, the results of the project provide a novel theoretical basis to measure the FVF and to investigate different sorts of the FVF.
Publications
- (2021). Fixation durations in free viewing search reveal target guidance and the functional visual field. 43rd European Conference on Visual Perception (ECVP), Visual meeting: 22-27 August
Ernst, D., & Wolfe, J.
- (2022). Fixation durations reveal the functional visual field in search through natural scenes. 22nd annual meeting of the Vision Sciences Society (V-VSS), Virtual meeting: 1-2 June
Ernst, D., & Wolfe, J.
- (2022). How fixation durations are affected by search difficulty manipulations. Visual Cognition, 30(5), 339-353
Ernst, D., & Wolfe, J.
(See online at https://doi.org/10.1080/13506285.2022.2063465)
