Neuropsychological aspects of simultaneous and successive cognitive processes

Abstract

The aim of this investigation was to examine the neuropsychological aspects of the model of information integration presented by Das et al. (1979). According to this model, information can be processed either simultaneously or successively and the domain for these modes of processing is, respectively, hypothesized to be in the posterior and anterior (fronto-temporal) divisions of the brain. Empirical verification of the model is provided in three studies: (1) adult neurological patients (N=121), (2) adult brain damaged patients (N=106), and (3) normal 75-84 years old people (N=58). Also, one case study is reported where the interactive nature of simultaneous and successive processing was observed in the sudden recovery from a profound aphemia. The factor analyses of simultaneous and successive tasks showed that the modes of processing were clearly identifiable but also showed differentiation according to the code content (verbal/nonverbal). In brain damaged sample, a two-way ANOVA revealed no interaction of laterality and anterior/posterior division in simultaneous or successive processing but instead two main effects of laterality on simultaneous verbal (p < .01) and successive (p < .05) processing. A very weak (p < .10) main effect of anterior/posterior division appeared on simultaneous nonverbal processing. In the third study, the neuropsychological factors were able to predict in regression analyses from 26 % to 43 % of the variance of the modes of processing. Also, it was observed that successive processing seemed to associate more with those neuropsychological tasks characterizing the functioning of the anterior lobe and simultaneous processing with that of the posterior lobe. Also, the results tentatively suggested the existence of separate units for simultaneous and successive processing in each hemisphere according to code content. Of related interest, it was found that educational level was the most influential background variable in relation to simultaneous and successive processing while the variables related to CNS disease showed no relationship to the modes of processing. Age correlated significantly with the modes of processing in each sample although weaker with simultaneous verbal processing. - The results gave support for construct and predictive validity of the model of simultaneous and successive processing.