Mean head and shoulder heights when seated: Subconscious postural cycles during discrete computerised stimuli
Authors: Witchel, H.J., Westling, C., Needham, R., Healy, A. and Chockalingam, N.
Journal: ACM International Conference Proceeding Series
Discrete, three-minute, computer-presented stimuli (designed to range from engaging to incredibly boring) were used to elicit changes in cognitive/emotional states in seated, healthy volunteers. These stimuli did not require the use of a mouse, so movements were assumed to be non- instrumental. Stimuli included films, games, quizzes and music. Motion capture and video analysis were used to detect changes in head and shoulder position in response to the stimuli. Results include changes occurring between the first half and the second half of each of the main stimuli (i.e. arising in less than one minute as the volunteer "settles in"); in the second half of each stimulus, there were decreases in head height and shoulder height (i.e. position rather than movement). In conclusion, we speculate that non-instrumental changes in head height and shoulder height may suggest loss of vigilance or diminishing arousal in seated computer-users. Our unique contributions are: 1) discrete stimuli, were used on seated volunteers 2) without a mouse, to show that 3) modest (mm) head and shoulder movements in the vertical axis correlated with 4) subtle cyclical changes in boredom, not overall changes in fatigue. Future psychological validation of tutoring systems with discrete stimuli can use these postural parameters as part of a multimodal analysis of engagement. © 2013 ACM.