Personality and Reactions to Sudden Events: Effects of Different Approaches to Modelling Physiological Reactions
Keywords:neuroticism, extraversion, electrodermal reaction, hierarchical linear modelling
AbstractThis study aimed to examine interindividual differences in electrodermal responses to a sudden stimulus by using different methods of electrodermal reaction assessment. Modelling the electrodermal response as a simple difference of mean electrodermal level before and after stimulus occurrence was compared with approaches that model the electrodermal response curve over time. The association of differently modelled electrodermal reaction with questionnaire measures of personality traits was examined. Ninety-seven students, mostly females (60 %), with age ranging from 18 to 28 participated in this study. Each subject completed a brief measure of neuroticism and extraversion from the Big Five Inventory (BFI; John et al., 1991, 2008) and participated in one laboratory measurement of electrodermal activity during a period of 8 minutes in which a sudden stimulus was presented. Electrodermal activity was modelled in three ways: 1) as a difference in pre- and post-stimulus responses; 2) including linear effects of time; 3) including quadratic effects of time. The outcomes of differently modelled electrodermal responses were correlated with questionnaire measures of neuroticism and extraversion. The results showed that by taking into account the effects of time (both linear and quadratic) the actual electrodermal data can be fitted significantly better. Likewise, estimates of the electrodermal response that take into account the effects of time result in both higher average response levels and interindividual variability. The electrodermal reaction modelled in this way (linear and quadratic) shows a slightly higher and significant positive correlation with neuroticism when compared to simpler methods, although the differences between the different modelling methods are relatively small. The results obtained support the idea of greater excitability related to the neuroticism trait. Given the intensity of the reaction, it is possible that the excitability associated with neuroticism is not specifically related to the valence of the stimulus that elicits that reaction. The correlations are extremely small, but they do not deviate from those obtained in other studies, especially since it is a single electrodermal measurement (Stemmler & Wacker, 2010). The results also show that correlations with personality traits can be detected even on a small sample and only one measurement by adequately modelling the electrodermal reaction.