There is a continuing debate in the field of perceptual organization as to whether the locus of global processing is early or late perceptual, as previous studies have yielded contrary results. The conducted behavioural study explored this issue with the paradigm of collating global processing with other process of perceptual organization, namely illusory contours processing. Interaction between these two processes of perceptual organization would indicate that global processing has an early perceptual locus, whereas the lack of such interaction would suggest (...) the late perceptual locus of global processing. In experiment 1, the effect of global dominance was obtained with the use of a compound figure composed of geometrical shapes with real edges. Results showed that the processing of the figure at the global level was faster and that it disrupted the processing of the figures from the local level. In experiment 1b, the compound figure was composed of local geometrical shapes generated with the use of the line-end induced illusory contours. Local elements with illusory contours did not affect the processing of the hierarchical structure and the effect of global precedence occurred without any changes. In experiment 2a, a global advantaged effect within a compound figure with local elements with real edges was obtained in the paradigm of attention divided between levels of the hierarchical structure. When illusory contours of local elements of a compound figure were introduced to this paradigm, this again had no effect on the perceptual global advantage. The results demonstrate the lack of interaction between global processing and illusory contour processing, indicating that the locus of global processing is rather late perceptual. (shrink)

Two priming experiments demonstrated exogenous attentional persistence to the fundamental auditory dimensions of frequency (Experiment 1) and time (Experiment 2). In a divided-attention task, participants responded to an independent dimension, the identification of three-tone sequence patterns, for both prime and probe stimuli. The stimuli were specifically designed to parallel the local–global hierarchical letter stimuli of [Navon D. (1977). Forest before trees: The precedence of global features in visual perception. Cognitive Psychology, 9, 353–383] and the task was designed to parallel subsequent (...) work in visual attention using Navon stimuli [Robertson, L. C. (1996). Attentional persistence for features of hierarchical patterns. Journal of Experimental Psychology: General, 125, 227–249; Ward, L. M. (1982). Determinants of attention to local and global features of visual forms. Journal of Experimental Psychology: Human Perception and Performance, 8, 562–581]. The results are discussed in terms of previous work in auditory attention and previous approaches to auditory local–global processing. (shrink)