Abstract
Theories on visual perception agree that visual recognition begins with global analysis and ends with detailed analysis. Different results from neurophysiological, computational, and behavioral studies all indicate that the totality of visual information is not immediately conveyed, but that information analysis follows a predominantly coarse-to-fine processing sequence (low spatial frequencies are extracted first, followed by high spatial frequencies). We tested whether such processing continues to occur in normally aging subjects. Young and aged participants performed a categorization task (indoor vs. outdoor scenes), using dynamic natural scene stimuli, in which they resorted to either a coarse-to-fine (CtF) sequence or a reverse fine-to-coarse sequence (FtC). The results show that young participants categorized CtF sequences more quickly than FtC sequences. However, sequence processing interacts with semantic category only for aged participants. The present data support the notion that CtF categorization is effective even in aged participants, but is constrained by the spatial features of the scenes, thus highlighting new perspectives in visual models.
Highlights
A considerable number of studies on the visual system in humans and animals suggest that spatial frequencies are crucial in visual perception
Two 26262 variance analyses (ANOVA), with Sequence of spatial frequency processing (CtF and fine-to-coarse sequence (FtC)) and Category as within-subject factors, and Age as between-subject factors were conducted on mean error rates and mean correct reaction times
The ANOVA conducted on mean error rates (mER) (Figure 2) showed a main effect of neither Age nor Sequence of spatial frequency processing (CtF: 565%; FtC: 465%; F1,44 = 1.77, p = 0.19)
Summary
A considerable number of studies on the visual system in humans and animals suggest that spatial frequencies are crucial in visual perception. Low spatial frequencies (LSF) in a visual input may be conveyed by the fast magnocellular visual pathway, and reach higher-order areas in the dorsal stream (parietal and frontal regions) and the ventral stream (inferotemporal regions) rapidly, allowing the initial perceptual parsing of visual inputs. This first coarse analysis might be refined by higher spatial frequency information (HSF), which is conveyed more slowly to the cerebral cortex by the parvocellular visual pathway
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