Shifts of Tonic Arousal Within and Between Tasks That Vary in Cognitive Demand

Abstract

Physiological data, such as respiration and electrodermal activity, can reveal significant details about a person’s thought process. These measures can be used in conjunction with a series of questions to evaluate credibility as in a lie detector test (Honts, 1994). Electrical conductance under the skin, referred to as electrodermal activity (EDA), occurs because of sympathetic neuronal activity, and is sensitive to changes in autonomic sympathetic arousal (i.e. – an underlying mechanism of the “fight or flight” response) (Critchley, 2002). Sweat glands contain the “fight or flight” hormone which is called cortisol. This hormone becomes innervated by the sympathetic neuronal activity, and can be a good indicator of a person’s automatic response. Since cortisol carries a weak electrical charge, this response is measured by recording micro-fluctuations of cortisol from the skin’s surface. Generally, EDA responses, or skin conductance responses (SCRs), measure arousal and have been used to look at the role of information processing, attention, emotion and even abnormal behavior on responding to a single controlled stimulus (Dawson, Schell & Filion, 2000). In other words, besides questions that may or may not be responded to truthfully, responses can be matched with stimuli, like a picture, word, or sound, to analyze correlations in shifting patterns of arousal, like in the case of studying emotional impact. One study looked at SCRs of participants who engaged in an attentional task involving positive, negative, and neutral stimuli, and found that for anxious and avoidant groups of people, negative pictures elicited larger SCRs (Silva, Ferreira, Soares & Esteves, 2015). The more arousal associated with a stimuli, the more changes in skin conductance.