“…We may say that of learning too, of course, which draws again attention to the question of whether engagement takes place as a series of actions over time, or is a qualitative aspect of a specific experience. When studying games, researchers have also used physiological techniques such as analysis of facial expressions and body language (Hughey, 2002), measurement of physiological factors such as heart rate and brain activity (Nacke & Lindley, 2008), and tracking of eye movements (Jennett et al, 2008;Renshaw et al, 2009). Objective measures, such as frameworks for evaluation of activities (Sweetser & Wyeth, 2005), observations (Read, MacFarlane, & Casey, 2002), game metrics such as frequency and duration (Ronimus, Kujala, Tolvanen, & Lyytinen, 2014), and voluntary time on task (Ronimus et al, 2014;Virvou, Katsionis, & Manos, 2004) have also been used.…”