Categorization versus distance: Hemispheric differences for processing spatial information

Abstract

It has been hypothesized that the brain computes two different kinds of spatial-relation representations: one used to assign a spatial relation to a category and the other used to specify metric distance with precision, The present visual half-field experiment offers support for this distinction by showing that the left and right cerebral hemispheres make more effective use of the categorization and metric distance representations, respectively. Furthermore, the inclusion of a bilateral stimulus presentation condition permits the computation of a reversed association that offers additional support for the distinction between two types of spatial-relation representation. Kosslyn (1987) has hypothesized that the human brain computes two different kinds of spatial-relation representations. One type of representation is used to assign a spatial relation to a category, such as "outside of' or "above," whereas the other type of representation preserves location information using a metric coordinate system in which distances are specified effectively. One way to obtain converging information about the plausibility of the distinction between these two processing subsystems is to show that they have different neurological substrata. With this in mind, Kosslyn has suggested that the left cerebral hemisphere makes more effective use of the categorization processing subsystem and that the right cerebral hemisphere makes more effective use of the metric distance processing subsystem. The present experiment was designed to provide tests of this lateralization hypothesis.On each trial of the present experiment, the subjects were shown a stimulus consisting of a horizontal line and a small dot in one of 12 possible locations (6 above the line and 6 below the line). During different experimental sessions, each subject performed a categorization task and a distance judgment task using these stimuli. Stimuli on different trials were presented to the right visual field-left hemisphere (RVF-LH) or the left visual field-right hemisphere (LVF -RH). It was of particular interest to determine whether or not there would be a task x visual field interaction (a processing dissociation, as discussed by Hellige, 1983, and Zaidel, 1983) and whether the interaction would be of the form predicted by Kosslyn's (1987) hypothesis. Because the stimuli and responses are identical for the categorization and distance-judgment tasks of the present experiment, any such interaction must The research reported here was supported in part by Research Grant BNS-8608893 from the National Science Foundation. The authors thank Alice Healy, Stephen Kosslyn, and two anonymous reviewers for helpful comments on an earlier draft of this manuscript. Correspondence may be sent to Joseph B. Hellige, Department of Psychology, University of Southern California, Los Angeles, CA 90089-1061. reflect differences in the processing subsystems required rather than other differences related to stimulus input (cf. .During the categorization task, the subjects were required to ind...

Processing of above/below categorical spatial relations by baboons (Papio papio)

“…In a previous study , we demonstrated baboon's ability to evaluate the distance between line-dot stimuli of the Hellige and Michimata's type (Hellige and Michimata, 1989). The aim of the present research was to extend our finding, by controlling if baboons can categorize line -dot stimuli on an 'above/below' basis.…”

“…Although the positive results on pigeons (Kirkpatrick-Steger and Wasserman, 1996) and chimpanzees (Hopkins and Morris, 1989) suggest the use of abstract spatial concepts, these results must be considered with caution, as the authors did not check if the animals could transfer their abilities to either novel stimuli or show them in novel experimental contexts. Hellige and Michimata (1989) and Kosslyn et al (1989) examined performance of human participants when evaluating distances and topological relations. Using stimuli made of a line and a dot, these studies suggested that two types of spatial representations are used in humans.…”

Picture the difference: electrophysiological investigations of picture processing in the two cerebral hemispheres

“…absolute distance) (e.g. [29,35,36]). One crucial difference between these types of spatial relations is that the former is reference frame dependent (e.g.…”

“…above/below) or metric (distance) terms (e.g. [1,29,36,40,60]), with left hemisphere processing more categorical and right hemisphere processing more metric in nature. Finally, the hemispheres also seem to differ in the extent to which they direct attention to global (whole object) or local (object part/feature) aspects of visual stimuli (e.g.…”

Differential impact of posterior lesions in the left and right hemisphere on visual category learning and generalization to contrast reversal

“…A hemispheric specialization for different types of visual attributes has been proposed by Kossslyn et al (1989), Hellige & Michimata (1989) and Rybash & Hoyer (1992) (see Jager & Postma, 2003, for a review). Accordingly, the right hemisphere possesses greater competence for the evaluation of metric coordinate representations, whereas the left hemisphere shows an advantage for the processing of categorical spatial relations.…”