In a number of studies the context provided by a real-world scene has been claimed to have a mandatory, perceptual effect on the identification of individual objects in such a scene. This claim has provided a basis for challenging widely accepted data-driven models of visual perception in order to advocate alternative models with an outspoken top-down character. The present paper offers a review of the evidence to demonstrate that the observed scene-context effects may be the product of post-perceptual and task-dependent guessing strategies. A new research paradigm providing an on-line measure of genuine perceptual effects of context on object identification is proposed. First-fixation durations for objects incidentally fixated during the free exploration of real-world scenes are shown to increase when the objects are improbable in the scene or violate certain aspects of their typical spatial appearance in it. These effects of contextual violations are shown to emerge only at later stages of scene exploration, contrary to the notion of schema-driven scene perception effective from the very first scene fixation. In addition, evidence is reported in support of the existence of a facilitatory component in scene-context effects. This is taken to indicate that the context directly affects the ease of perceptual object processing and does not merely serve as a framework for checking the plausibility of the output of perceptual processes. Finally, our findings are situated against other contrasting results. Some future research questions are high-lighted.

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Human observers are experts at face recognition, yet a simple 180 degrees rotation of a face photograph decreases recognition performance substantially. A full understanding of this phenomenon-which is believed to be important for clarifying the nature of our expertise in face recognition-is still waiting. According to a long-standing and influential hypothesis, an inverted face cannot be perceived as holistically as an upright face and has to be analyzed local feature by local feature. Here, we tested this holistic perception hypothesis of the face inversion effect by means of a gaze-contingent stimulus presentation. When observers' perception was restricted to one fixated feature at a time by a gaze-contingent window, performance in an individual face matching task was almost unaffected by inversion. However, when a mask covered the fixated feature, preventing the use of local information at high resolution, the decrement of performance with inversion was even larger than in a normal-full view-condition. These observations provide evidence that the face inversion effect is caused by an inability to perceive the individual face as a whole rather than as a collection of specific features and thus support the view that observers' expertise at upright face recognition is due to the ability to perceive an individual face holistically.

Stimulus displacements coinciding with a saccadic eye movement are poorly detected by human observers. In recent years, converging evidence has shown that this phenomenon does not result from poor transsaccadic retention of presaccadic stimulus position information, but from the visual system's efforts to spatially align presaccadic and postsaccadic perception on the basis of visual landmarks. It is known that this process can be disrupted, and transsaccadic displacement detection performance can be improved, by briefly blanking the stimulus display during and immediately after the saccade. In the present study, we investigated whether this improvement could also follow from a discontinuity in the task-irrelevant form of the displaced stimulus. We observed this to be the case: Subjects more accurately identified the direction of intrasaccadic displacements when the displaced stimulus simultaneously changed form, compared to conditions without a form change. However, larger improvements were still observed under blanking conditions. In a second experiment, we show that facilitation induced by form changes and blanks can combine. We conclude that a strong assumption of visual stability underlies the suppression of transsaccadic change detection performance, the rejection of which generalizes from stimulus form to stimulus position.

Multiple times per second, the visual system succeeds in making a seamless transition between presaccadic and postsaccadic perception. The nature of the transsaccadic representation needed to support this was commonly thought to be sparse and abstract. However, recent studies have suggested that detailed visual information is transferred across saccades as well. Here, we seek to confirm that preview effects of visual detail on postsaccadic perception do indeed occur. We presented subjects with highly similar artificial shapes, preceded by a congruent, an incongruent, or no preview. Postsaccadic recognition performance was measured, while the contrast of presaccadic and postsaccadic stimuli was manipulated independently. The results show that congruent previews provided a benefit to the recognition performance of postsaccadic stimuli, compared to no-preview conditions. Incongruent previews induced a recognition accuracy cost, combined with a recognition speed benefit. A second experiment showed that these effects can disappear when stimulus presentation is interrupted with a postsaccadic visual mask. We conclude that visual detail contained in transsaccadic memory can affect the postsaccadic percept. Furthermore, we find that the transsaccadic representation supporting this process is contrast-independent, but that postsaccadic contrast, through its effect on the reliability of information, can affect the degree to which it is employed.