The cerebral balance of power: Confrontation or cooperation?

Abstract

Two visual search experiments were carried out using as stimuli large letters made of small identical letters presented in right, or left, or central visual fields. Considering the spatial frequency contents of the stimuli as the critical variable, Experiment 1 showed that a left-field superiority could be obtained whenever a decision had to be made on a large (low frequency) letter alone, and a right-field advantage emerged when a small (high frequency) letter had to be processed. Experiment 2 showed that the two levels of structure of the stimulus were not encoded at the same rate and that at very brief exposure, only the large letter could be accurately identified. This was accompanied by a left-field superiority, whether or not the stimulus contained the target. These results are interpreted as revealing a differential sensitivity of the hemispheres to the spatial frequency contents of a visual image, the right hemisphere being more adept at processing early-available low frequencies and the left hemisphere operating more efficiently on later-available low frequencies. From these and other experiments reviewed, it is suggested that (a) cerebral lateralization of cognitive functions results from differences in sensorimotor resolution capacities of the hemispheres; (b) both hemispheres can process verbal and visuospatial information, analytically and holistically; (c) respective hemispheric competence is a function of the level of sensorimotor resolution required for processing the information available.

Spatial Frequency and Face Processing in Children with Autism and Asperger Syndrome

“…In contrast, when faces are high-pass filtered, the contrasts are increased, which renders the facial features highly salient. A greater use of low-than of high-spatial frequency information in face processing has been supported by numerous studies on normal adults (e.g., Fiorentini, Maffei, & Sandini, 1983;Schyns & Oliva, 1999;Sergent, 1982Sergent, , 1986, thus confirming the predominance of configural processing in face recognition (e.g., Tanaka & Farah, 1993).…”

Auditory attention to frequency and time: an analogy to visual local–global stimuli

“…Kim, Ivry, & Robertson, 1999;Martin, 1979;Navon, 1977;Robertson, 1996;Sergent, 1982;Shulman & Wilson, 1987;Ward, 1982). The stimuli have also been used in neuropsychological research to examine how the brain implements localglobal processing in an asymmetric manner, with the left and right hemispheres more attuned to local and global levels, respectively (e.g.…”

Illusory conjunctions and the cerebral hemispheres

“…Hemispheric Specialization Sergent (1982) obtained RVF and LVF superiorities for the identification of small and large letters, respectively. On the basis of these and other data, she proposed that the left hemisphere is preferentially sensitive to high spatial frequencies, whereas the right hemisphere deals with low spectral information.…”

“…ICs were actually predicted by Anne Treisman's theory of object perception, which involves two stages of processingthat is, a stage of feature extraction followed by a stage of feature integration (Treisman, 1988;Treisman & Gelade, Copyright 1993 Psychonomic Society, Inc. a Star of David or a cross, respectively (see examples in Figures Ia, lb, lc and la', lb', l c'). Sergent (1982) obtained the predicted change in laterality effects for forms subtending visual angles similar to the ones we used (see Van Kleeck, 1989). Although size effects may possibly be interpreted in the context of the spatial frequency approach of laterality differences (Sergent, 1982), we wish to state that testing this notion was not a purpose of the present study.…”

“…Sergent (1982) obtained the predicted change in laterality effects for forms subtending visual angles similar to the ones we used (see Van Kleeck, 1989). Although size effects may possibly be interpreted in the context of the spatial frequency approach of laterality differences (Sergent, 1982), we wish to state that testing this notion was not a purpose of the present study.…”