Influence of stimulus location information on performance assessed by Simon task: Does Simon effect vary with age?

Vishnu Priyadharshini V¹,
Anbuselvi Mattuvar Kuzhali S²,
Ratna Manjushree J³

¹Post Graduate,
Institute of Physiology and Experimental Medicine,
Madras Medical College,
Chennai, Tamilnadu, India
²Assistant Professor,
Institute of Physiology and Experimental Medicine,
Madras Medical College,,
Chennai, Tamilnadu, India
³Professor & Head,
Thiruvannamalai Medical College,
Thiruvannamalai, Tamilnadu, India

Abstract
  • Introduction: Simon tasks are tests to study the cognitive control and inhibition process. Amongst stages of information processing: stimulus identification, response selection, and response execution, the response-selection is assessed by Simon effect. How the stimulus properties change the response? How the location information does affect the response when it is irrelevant to the task? We intended to identify how this judgement of stimuli varies with age.
  • Aim: To estimate and compare the reaction time in milliseconds between the compatible / incompatible stimuli and Simon effect of Simon task amongst different age groups.
  • Materials and Methods: 176 clinically healthy of age (18-50) years of both males and females with basic computer knowledge were recruited. After clear instructions, all subjects were asked to perform software based cognitive tasks, stimulus-response compatibility test (Simon effect) with 40 trails, Right/Left stimulus, and compatibility reaction. Data were recorded as reaction time of the average responses in Simon task and analyzed using SPSS.
  • Results and discussion: Reaction time increases more for incompatible stimuli than compatible stimuli (p=0.000), and increased more for older individuals than young adults. Simon effect is measured as increased cognitive load which emphasize cognitive error processing/resolving information during each stimulus.
  • Conclusion: Responses are speeded when the stimulus is displayed on the same side as the response compared to when it is displayed on the opposite side. This effect of spatial correspondence decreases with increase in age.

Keywords: Attention, Response-selection, Simon effect