Abstract
Influences of target features on fixation locations and search durations have been widely studied. What happens to properties of the eyes' scanpath when looking for different targets has not been investigated as thoroughly. One important target aspect is how far into the periphery it is detectable, which can be varied by changing its spatial frequency content. Here we show that human participants adapt their eye movement behavior immediately when searching for different targets in natural scenes. In our study, participants searched natural scenes for 6 artificial targets with different spatial frequency content. High spatial frequency targets led to shorter fixation durations and smaller saccade amplitudes than low spatial frequency targets. The effect of the smaller saccade amplitudes appeared from the first of eight experimental sessions, without training, persisted throughout all sessions and disappeared when subjects were not told which of the targets to search for. Fixation durations were shorter for high spatial frequency targets after one training session, also persisted throughout all subsequent sessions and disappeared when subjects were not told which of the targets to search for. The differences in eye movement patterns between low and high spatial frequency targets led to longer search times to find the high frequency targets, but the probability to find the target within 10 seconds was unchanged. As high spatial frequency targets can not be detected far into the periphery, it is adaptive to choose a scanning strategy with shorter fixation durations and shorter saccade amplitudes when searching for high spatial frequency targets. Our results suggest that humans are capable to adequately adapt their eye movement behavior instantaneously according to the spatial frequency content of the target, implicitly adapting to how far from the fovea targets can be detected.
Meeting abstract presented at VSS 2017