@misc{cogprints4429, volume = {9}, title = {User-hostile systems and patterns of psychophysiological activity}, author = {Paul Muter and J.J. Furedy and A. Vincent and T. Pelcowitz}, publisher = {Computers in Human Behavior}, year = {1993}, pages = {105--111}, journal = {Computers in Human Behavior}, keywords = {usability, psychophysiology}, url = {http://cogprints.org/4429/}, abstract = {Psychophysiological measures, which are not contaminated by demand characteristics, are potentially useful for improving systems and for examining psychological processes in human-computer interaction. In this study we report the use of minute-by-minute scored heart-rate (HR) and skin-conductance level (SCL) in a 25-subject experiment. Each subject was presented with two simulated bank-transaction tasks, one user-friendly and the other user-hostile. To check whether any differences were due simply to sheer difficulty, easy (forward digit-span) and hard (backward digit-span) memory tasks were presented to all subjects. The HR was higher during the computer (problem-solving) tasks than the memory tasks, but was unaffected by task difficulty, whereas SCL was uniquely elevated during the hard (user-hostile) computer task. The HR result is interpreted as reflecting parasympathetic withdrawal, while the SCL result suggests that the user-hostile software produced sympathetic excitation of the sort associated with the fight-or-flight reaction. SCL may serve as a good measure of user-friendliness.} }