Abstract
The spatial distance between two simultaneous presented pictures determines comparative visual search (CVS) behavior. With increasing distance, humans conduct fewer gaze-shifts between two simultaneously presented pictures when searching differences, suggesting a higher use of the visual short-term memory (VSTM). Previous research examined search behavior with pictures presented next to each other thus not only varying spatial but also temporal distances as the gaze-shift duration increases with increasing distance between picture pairs. In this study we examined the contribution of pure temporal distances to the trade-off between the number of changes between pictures and VSTM use. We hypothesized that longer temporal distances between two alternating images leads to higher VSTM use. We further hypothesized a higher use of chunking strategies for participants with domain knowledge. Prior to the search task participants received either stimulus-related or -unrelated information thus manipulating domain knowledge. Participants had to search for differences between two pictures of a pendulum clock that were presented on one display one at a time. They could alternate between them by pressing a key. The change was delayed by 120 or 500 ms. We measured the number of shifts between the pictures and recorded gaze behavior. Results showed a trade-off between the number of shifts between pictures and the temporal distance. This replicates effects known from CVS with pure temporal instead of both temporal and spatial distances. Further, participants with domain knowledge conducted a smaller number of shifts in both distance conditions suggesting a higher use of chunking strategies. Eye tracking data complement the findings. Participants who received domain knowledge showed a fewer number of fixations and smaller saccade amplitudes. This is in line with findings in eye tracking literature. In sum, there is an influence of domain knowledge on the replicated trade-off in a temporal CVS paradigm.