@article{CajarEngbertLaubrock2020,
  author    = {Cajar, Anke and Engbert, Ralf and Laubrock, Jochen},
  title     = {How spatial frequencies and color drive object search in real-world scenes},
  series = {Journal of vision},
  volume    = {20},
  journal   = {Journal of vision},
  number    = {7},
  publisher = {Association for Research in Vision and Opthalmology},
  address   = {Rockville},
  issn      = {1534-7362},
  doi       = {10.1167/jov.20.7.8},
  pages     = {16},
  year      = {2020},
  abstract  = {When studying how people search for objects in scenes, the inhomogeneity of the visual field is often ignored. Due to physiological limitations, peripheral vision is blurred and mainly uses coarse-grained information (i.e., low spatial frequencies) for selecting saccade targets, whereas high-acuity central vision uses fine-grained information (i.e., high spatial frequencies) for analysis of details. Here we investigated how spatial frequencies and color affect object search in real-world scenes. Using gaze-contingent filters, we attenuated high or low frequencies in central or peripheral vision while viewers searched color or grayscale scenes. Results showed that peripheral filters and central high-pass filters hardly affected search accuracy, whereas accuracy dropped drastically with central low-pass filters. Peripheral filtering increased the time to localize the target by decreasing saccade amplitudes and increasing number and duration of fixations. The use of coarse-grained information in the periphery was limited to color scenes. Central filtering increased the time to verify target identity instead, especially with low-pass filters. We conclude that peripheral vision is critical for object localization and central vision is critical for object identification. Visual guidance during peripheral object localization is dominated by low-frequency color information, whereas high-frequency information, relatively independent of color, is most important for object identification in central vision.},
  language  = {en}
}
@article{CajarSchneeweissEngbertetal.2016,
  author    = {Cajar, Anke and Schneeweiß, Paul and Engbert, Ralf and Laubrock, Jochen},
  title     = {Coupling of attention and saccades when viewing scenes with central and peripheral degradation},
  series = {Journal of Vision},
  volume    = {16},
  journal   = {Journal of Vision},
  number    = {2},
  publisher = {ARVO},
  address   = {Rockville, Md.},
  issn      = {1534-7362},
  doi       = {10.1167/16.2.8},
  pages     = {1 -- 19},
  year      = {2016},
  abstract  = {Degrading real-world scenes in the central or the peripheral visual field yields a characteristic pattern: Mean saccade amplitudes increase with central and decrease with peripheral degradation. Does this pattern reflect corresponding modulations of selective attention? If so, the observed saccade amplitude pattern should reflect more focused attention in the central region with peripheral degradation and an attentional bias toward the periphery with central degradation. To investigate this hypothesis, we measured the detectability of peripheral (Experiment 1) or central targets (Experiment 2) during scene viewing when low or high spatial frequencies were gaze-contingently filtered in the central or the peripheral visual field. Relative to an unfiltered control condition, peripheral filtering induced a decrease of the detection probability for peripheral but not for central targets (tunnel vision). Central filtering decreased the detectability of central but not of peripheral targets. Additional post hoc analyses are compatible with the interpretation that saccade amplitudes and direction are computed in partial independence. Our experimental results indicate that task-induced modulations of saccade amplitudes reflect attentional modulations.},
  language  = {en}
}
@article{CajarSchneeweissEngbertetal.2016,
  author    = {Cajar, Anke and Schneeweiss, Paul and Engbert, Ralf and Laubrock, Jochen},
  title     = {Coupling of attention and saccades when viewing scenes with central and peripheral degradation},
  series = {Journal of vision},
  volume    = {16},
  journal   = {Journal of vision},
  publisher = {Association for Research in Vision and Opthalmology},
  address   = {Rockville},
  issn      = {1534-7362},
  doi       = {10.1167/16.2.8},
  pages     = {19},
  year      = {2016},
  abstract  = {Degrading real-world scenes in the central or the peripheral visual field yields a characteristic pattern: Mean saccade amplitudes increase with central and decrease with peripheral degradation. Does this pattern reflect corresponding modulations of selective attention? If so, the observed saccade amplitude pattern should reflect more focused attention in the central region with peripheral degradation and an attentional bias toward the periphery with central degradation. To investigate this hypothesis, we measured the detectability of peripheral (Experiment 1) or central targets (Experiment 2) during scene viewing when low or high spatial frequencies were gaze-contingently filtered in the central or the peripheral visual field. Relative to an unfiltered control condition, peripheral filtering induced a decrease of the detection probability for peripheral but not for central targets (tunnel vision). Central filtering decreased the detectability of central but not of peripheral targets. Additional post hoc analyses are compatible with the interpretation that saccade amplitudes and direction are computed in partial independence. Our experimental results indicate that task-induced modulations of saccade amplitudes reflect attentional modulations.},
  language  = {en}
}