Examining the efficiency in tasks of signal detection within subjects with different personality traits  

Škrinjarić L.
University of Zadar, Department of Psychology, Zadar, Croatia

Previous researches showed subject's efficiency decline in performing a monotonous task, like Mackworth's clock, as the function of task duration. It has also been shown that there is a difference in the task performing efficiency regarding the signal detection between introverts and extroverts. This is usually explained by higher level of cortical arousal within introverts for which they show lower decline of efficiency than the extroverts. The aim of this research was to examine the changes of efficiency in detecting signals of different duration with regard to dimensions of extroversion and neuroticism, and to determine possible changes within the parameters of ECG in the function of task duration within subjects with different personality traits. The research was performed on a group of students (N = 20). On the basis of results obtained by Eysenck's personality questionnaire, the subjects were divided into 2 groups, with 10 subjects each (with regard to the dimensions of extraversion). During the research a computer with an adequate software (Mackworths's clock) and an ECG device (PowerLab System) were used. As expected, changes within all parameters regarding subjects' efficiency in the function of task duration were found, except for the proportion of false alarms. Subject's efficiency significantly decreases as a function of task duration. Statistically significant difference between extroverts and introverts was found only for the proportion of false alarms. Although introverts showed a tendency of better efficiency than the extroverts, the differences between groups were not significant on any examined efficiency parameter. Changes in heart frequency and sinus arrhythmia (mean values of R-R intervals and parameters of SD and SDD) showed a general tendency of tranquilizing subjects' organism as a function of task duration, as well as the differences between personality traits. Introverts had a lower mean values and lower variability of R-R intervals (SD and SDD).