The ease and efficiency with which we perceive objects in daily life masks the complexity of the processes involved. The main goal of my doctoral research was to enhance our understanding of the complex interplay between perceptual organization and object recognition. To this end, we investigated the dynamic interplay between different component processes of object recognition, and their temporal dynamics. In the first part of this thesis, I present three behavioral studies focusing on the role of different features of an objects shape (e.g., local contour information). In the second part of this thesis, I present our neuropsychological work, including a case study and the development of a new screening test for perceptual organization (L-POST). In a first behavioral study (Chapter 2), we used a dynamic build-up paradigm with fragmented outlines to investigate the interplay between grouping and matching processes during object recognition. We tried to disentangle the influence of configural shape information such as symmetry and complexity, and local contour information. Our results revealed a dominance of global configural properties during early grouping processes, compared to local fragment properties (i.e., fragment curvature) or more local configural properties (e.g., proximity). In the following two behavioral studies (Chapters 3 & 4), we investigated the role of within trial top-down processing when people recognize objects, and emphasizing the role of candidate interpretations. We focused on the contribution of different spatial frequencies in their formation, and the time-windows in which they are most effective. In a pre-study with long exposures, participants were asked to list all potential objects that could have given rise to the low-pass filtered pictures. In two priming experiments with short exposures, participants had to classify the objects as natural or manmade, or they had to name them. The results showed that the number of candidate interpretations generated by the low-spatial frequencies of the target influences the occurrence of recognition responses, but only when response latency is long, and all candidates belong to the same category as the target. In Chapter 5, we investigated how global shape information and local contour information influence object identification in a patient with a category-specific impairment for natural objects. We used systematically degraded stimuli (fragmented outlines) to manipulate the quality of the visual representation of the object. The paradigm was similar to the one used in our first behavioral study (Chapter 2). We found evidence that category-specific deficits for natural objects do not only arise at a semantic level, but also reflect poor visual grouping and access to visual knowledge. In Chapter 6, I describe the Leuven Perceptual Organization Screening Test (L-POST) in which a wide range of processes of perceptual organization are measured. The L-POST consists of 15 subtests screening for various aspects of perceptual organization, e.g. figure-ground segregation, contour integration, or local and global processing. To reduce cognitive load, a matching-to-sample task is used for all test items: Participants have to indicate the alternative that is the most similar to the target stimulus. This computerized test can be administered in 30-45 minutes, and a neglect friendly version is also available. To conclude, the research of my doctoral project has enhanced our understanding of the temporal dynamics of different component processes during object recognition. Moreover, our results emphasize the perceptual value of coarse shape information in the activation of candidate interpretations during object recognition. More generally, our results highlight the need to control for the moment of responding in behavioral studies by using an appropriate statistical technique such as survival analysis. nrpages: 196 status: published