“…To address these drawbacks, direct measurements of physiological responses such as heart rate (HR; or pulse rate [PR] when measured using photoplethysmography [PPG]), heart rate variability (HRV), electrodermal activity (EDA), skin temperature (ST), cortisol levels, blood pressure, and pupil diameter data have been investigated for assessment of stress (Greene et al, 2016) and other related constructs such as workload and arousal (Hancock & Matthews, 2019; Matthews et al, 2015). The recent evolution and availability of HR, EDA, and ST sensor technology has enabled continuous collection of physiological responses in real-world settings and has empowered naturalistic research (Healey & Picard, 2005; Jenks et al, 2020; Mehler et al, 2012; Rodrigues et al, 2015; Schneegass et al, 2013). While naturalistic studies of stress using wearable sensors (e.g., Chen et al, 2014; Giakoumis et al, 2012; Giannakakis et al, 2017; Gjoreski et al, 2017; McDuff et al, 2014) have shown promise in complementing participant self-report and simulated laboratory-based measurement, the correlations between several psycho-physiological responses used to assess stress have not been documented in unconstrained and naturalistic environments.…”