Discrete vs Continous Stimuli

The first crucial step when designing an EDA study is to decide on the type of stimulus to be used. Depends on the goal of their study and the type of their stimulus researchers have to pick from three paradigms for using EDA-presenting discrete stimuli, presenting continuous stimuli, and investigating the correlation of individual traits and EDA [12]. According to Babaei et. al. [24] EDA practices in CHI only involved only the first two paradigms.

- First Paradigm: When designing a study where a series of discrete stimuli, each lasting a few seconds, is presented to participants, interleaved with rest periods (Inter-Stimulus Interval (ISI)), researchers shall use phasic parameters of the EDA signal. The phasic parameters enable measuring novelty, significance, and intensity of the stimuli used. Orienting response is the only discrete stimulus paradigm employed in CHI to date [24].

- Second Paradigm: Contrary to the first paradigm, studies investigating the effect of continuous stimuli, such as long lasting situations or tasks, on EDA, shall analyse the tonic parameters of the EDA signal. Tonic parameters, such as SCL and NS.SCR frequency, are defined by the before-mentioned slow response to changes in conditions such as cognitive workload or stress. SCL and NS.SCR frequencies are the most common measures in this paradigm, which is the most widely used paradigm in current EDA studies published at CHI.