Time-course contingencies in perceptual organization and identification of fragmented object outlines : Identification hazard of fragmented object outlines

To study the dynamic interplay between different component processes involved in the identification of fragmented object outlines, a discrete-identification paradigm was used in which the masked presentation duration of fragmented object outlines was repeatedly increased until correct naming occurred. Survival analysis was used to investigate whether and when different types of information such as contour integration cues (proximity, collinearity, and fragment density), fragment properties (low versus high curvature), stimulus complexity (global symmetry, number and saliency of the parts), and memory factors (natural versus artifactual), influenced the timing of identification. The results showed that the importance of these different types of information can change over the time course of object identification, indicating so-called time-course contingencies. Most importantly, the straight segments of a contour played a larger role for complex outlines with high part saliency during early (bottom-up) grouping processes, whereas the curved segments of object outlines were more important during later (top-down) matching processes for simpler outlines with lower part saliency. This new insight can explain why different studies on shape-based object identification have produced seemingly contradictory results. ispartof: Journal of Experimental Psychology: Human Peception and Performance vol:35 issue:3 pages:661-687 ispartof: location:United States status: published