During everyday scene viewing, the information received by the visual system is frequently disrupted: Objects are often occluded by other objects, and sensory processing is interrupted by eye, head, or body movements. The visual system is extremely efficient at correcting for these interruptions and in establishing object correspondence and perceptual continuity. At the end of this correspondence process, the visual system is left with two representations of an object: The initial representation and the one acquired after the disruption. In the present dissertation, I investigated the mechanisms by which the visual system reconciles these discontinuous inputs to give us a perception of a smooth and stable visual world. To achieve this, I ran four experiments in which participants were presented with a colored saccade target, and instructed to remember its color before executing the saccade. On some trials, the color of the saccade target was changed to a new value during the saccade. Participants were asked to report either the pre- or post-saccadic color value in a continuous report task. Object continuity was manipulated in two ways. The target blanking paradigm served as the main manipulation of stability: On half the trials, the target was removed from the screen during the saccade, disrupting object continuity. In addition, the magnitude of color change was used as a secondary manipulation of visual stability. The color report data were fit with probabilistic mixture models. First, there was no evidence for integration of pre- and post-saccadic feature values into a composite representation. Instead, on a majority of trials participants could successfully retain and report both pre- and post-saccadic states of the target object. Further, these two states dynamically interacted with each other, resulting in their feature values systematically shifting toward each other. Lastly, when reporting the pre-saccadic color, participants were more likely to incorrectly report the post-saccadic color under conditions of visual stability versus instability, supporting a probabilistic overwriting mechanism. Together, these results are more consistent with an object-based model, rather than an image-based model of representational updating. Although the present study only focused on transsaccadic updating mechanisms, similar mechanisms are likely to be functional in many common situations where the visual system needs to establish perceptual continuity across disruptions and changes.

Chaque saccade oculaire décale brusquement l'image projetée sur la rétine. Pourtant notre perception du monde reste stable et uniforme car le système visuel fait correspondre les informations avant et après chaque saccade. Pour établir cette correspondance, les mécanismes attentionnels seraient fondamentaux. Jusqu'à présent, ce lien transsaccadique a été mis en évidence par des études portant essentiellement sur le traitement des informations spatiales - à savoir, comment la position rétinienne d'un objet est corrigée à chaque saccade pour maintenir une perception stable du monde. Le traitement des traits visuels tels que la couleur ou la forme est encore mal compris et leur rôle dans l'impression de stabilité reste à établir. Est-ce que les traits et l'attention dédiée aux traits (feature-based attention), par définition indépendants de l'espace, participent aussi à la correspondance transsaccadique ? Pour analyser la relation entre le traitement des traits et celui des positions lors des saccades oculaires, cette thèse a suivi deux approches. La première s'est intéressée à la perception des attributs visuels, uniforme malgré l'hétérogénéité du système visuel. Les résultats ont montré que si la perception uniforme des attributs visuels s'appuie sur un apprentissage, les mécanismes sous-jacents ne seraient pas spécifiques aux mouvements oculaires. L'uniformité de la perception s'appuierait plutôt sur un mécanisme d'apprentissage associatif général. La seconde approche a cherché à mieux comprendre la nature de l'attention sélective transsaccadique. Les résultats ont montré que l'attention allouée à la cible d'une saccade ne contribue pas à aux mécanismes sélectifs guidés par les traits et engagés juste après l'exécution d'un mouvement oculaire. L'attention allouée à une cible saccadique et l'attention aux traits seraient alors indépendantes. Enfin, la dernière étude a montré que, lorsque l'attention sélective basée sur les traits est engagée pendant la préparation de la saccade en dehors de la cible saccadique, les traits sont maintenus pendant la saccade et affectent les processus sélectifs engagés juste après la saccade. L'attention transsaccadique ne serait alors pas de nature purement spatiale. L'ensemble de ces résultats suggère que les traits et l'attention aux traits joueraient un rôle dans la correspondance transsaccadique. / With each saccade, the image on the retina shifts abruptly but our perception of the surrounding world remains stable and uniform, because the visual system matches pre- and post-saccadic visual information. Attentional mechanisms could play a fundamental role in this process and numerous studies have examined the role of spatial attention. The processing of feature-based attention across saccades remains unclear and its role in matching pre- to post-saccadic visual information is not known. Do visual features and feature-based attention, assumed to enhance the feature-specific representations throughout the visual field, take part in the transsaccadic correspondence? To examine the relationship between feature and spatial processing, this thesis chose two approaches. The first one considered the uniform perception that we have for features despite the heterogeneity of the retina. Results show that, if the transsaccadic correspondence of visual features relies on learning, the underlying mechanisms would not be specific to eye movements. Visual constancy is more likely to arise from a general associative learning. The second approach examined the nature of transsaccadique attention. Results show that attention drawn to the saccade target did not contribute to selective mechanisms engaged just after an eye movement, suggesting a dissociation between feature-based attention and saccade programming. Finally, the last study show that feature-based selectivity is maintained across saccades to ensure spatiotopic correspondence, pointing out the potential role of feature-based attention in matching pre- to post-saccadic information.