Neuroticism related differences during porcessing of controlled congnitive tasks

Abstract

It is suggested that neuroticism impairs cognitive performance mostly in difficult tasks i.e. WM tasks, but not so much in easier tasks. However, behavioural, and functional neuroanatomical correlates of detrimental effect of neuroticism in relation to central executive system (CES) during cognitive tasks particularly in multitasking still unknown. I aim at investigating behavioural and functional neuroanatomical correlates of single- and dual-task performance in high and low neurotics. The general hypothesis is that high neurotics will show a poorer performance on processing of cognitive tasks as compared to low neurotics. From a screened population, I select low neurotics (below 6) and high neurotics (over 16) on 24 item Eysenck Personality Questionnaire (EPQ) neuroticism scale. First empirical study was consisted of three standard WM tests. The result of this study showed that high neurotics had lower performance when the task heavily requires CES such as switching and inhibition. Next empirical studies were consisted of dual tasks based on PRP paradigm. In dual task studies, in addition to SOA manipulation SOA (0 and1000ms), task demand manipulated either by presentation of task order or task set maintenance. The results show that high neurotics considerably slower when SOA is short. Further, it has been observed dual task cost differences between high and low neurotics increase as the demand increase either by random tasks or task set maintenance as evident by lower processing efficiency in high neurotics. Also, high neurotics perceived higher stress level as the task demand increase. In the final study, I assessed brain activity by means of functional magnetic resonance imaging (fMRI) in low and high neurotics while they were performing a demanding dual-task and the less demanding component tasks as single-tasks. Imaging data showed that high neurotics showed less dual-task specific activation in lateral and medial prefrontal cortices. In conclusion, I conclude that high levels of neuroticism impair behavioural performance in demanding tasks with higher perceived stress level, and that this impairment is accompanied by reduced activation of the task-associated brain areas. Key words: Neuroticism, Personality, Multitasking, dual-task performance, prefrontal cortex attentional control theory, working memory.