![]() However, changing something as simple as the direction of illumination leads to complex changes in the face image, including changes in shading gradients and in the shapes and locations of shadows. Humans can effortlessly recognize faces and objects under a wide variety of lighting conditions. The results also suggest that face representations retain illumination information. These results demonstrate that peripheral viewing, rather than display changes, can explain why changes in illumination direction do not affect performance when position changes. Changing the illumination direction did not affect performance. In Experiment 3, all faces were presented peripherally without shadows. In both experiments, shadows did not affect performance, in contrast to earlier findings ( Braje, Kersten, Tarr, & Troje, 1998). ![]() Performance was illumination-dependent regardless of whether position changed. A fixation cross cued each face’s location, such that observers could move their eyes to view each face centrally. Experiment 2 tested whether this could be explained by peripheral viewing on different-position trials. In Experiment 1, performance was illumination-dependent only on same-position trials, suggesting that observers used display changes. The faces were illuminated from the same or different directions, and were presented in the same or different positions on the screen. Observers judged whether two sequentially-presented faces, shown with or without cast shadows, were the same person. ![]() Three experiments explore whether this impairment can be explained by display changes ( Biederman & Bar, 1999), and whether cast shadows help or hinder face recognition. Recognition of faces and objects is impaired when illumination direction varies.
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