Response selection and attention orienting: a computational model of Simon effect asymmetries.
Recently, there has been a redirection of research efforts toward the exploration of the role of hemispheric lateralization in determining Simon effect asymmetries. The present study aimed at implementing a connectionist model that simulates the cognitive mechanisms implied by such asymmetries, focusing on the underlying neural structure. A left-lateralized response-selection mechanism was implemented alone (Experiment 1) or along with a right-lateralized automatic attention-orienting mechanism (Experiment 2). It was found that both models yielded Simon effect asymmetries. However, whereas the first model showed a reversed pattern of asymmetry compared with human, real data, the second model's performance strongly resembled human Simon effect asymmetries, with a significantly greater right than left Simon effect. Thus, a left-side bias in the response-selection mechanism produced a left-side biased Simon effect, whereas a right-side bias in the attention system produced a right-side biased Simon effect. In conclusion, results showed that the bias of the attention system had a larger impact than the bias of the response-selection mechanism in producing Simon effect asymmetries.
Department of general psychology, University of Padova, Padova, Italy. chiara.spironelli@unipd.it
Chiara
C
Spironelli
Mariaelena
M
Tagliabue
Carlo
C
Umiltà
D001245:Association Learning / Q000502:physiology; D001288:Attention / Q000502:physiology*; D003118:Color Perception / Q000502:physiology*; D003220:Conflict, Psychological; D003337:Corpus Callosum / Q000502:physiology; D004192:Discrimination, Psychological / Q000502:physiology; D004292:Dominance, Cerebral / Q000502:physiology*; D005625:Frontal Lobe / Q000502:physiology; D007839:Functional Laterality / Q000502:physiology; D006801:Humans; D009044:Motor Cortex / Q000502:physiology; D009415:Nerve Net / Q000502:physiology; D016571:Neural Networks, Computer; D009949:Orientation / Q000502:physiology*; D011597:Psychomotor Performance / Q000502:physiology*; D011930:Reaction Time / Q000502:physiology*