Further Investigating Pen Gesture Features Sensitive to Cognitive Load

A person‟s cognitive state and capacity at a given moment strongly impact decision making and user experience, but are still very difficult to evaluate objectively, unobtrusively, and in real-time. Focusing on smart pen or stylus input, this paper explores features capable of detecting high cognitive load in a practical set-up. A user experiment was conducted in which participants were instructed to perform a vigilance-oriented, continuous attention, visual search task, controlled by handwriting single characters on an interactive tablet. Task difficulty was manipulated through the amount and pace of both target events and distractors being displayed. Statistical analysis results indicate that both the gesture length and width over height ratio decreased significantly during the high load periods of the task. Another feature, the symmetry of the letter „m‟, shows that participants tend to oversize the second arch under higher mental loads. Such features can be computed very efficiently, so these early results are encouraging towards the possibility of building smart pens or styluses that will be able to assess cognitive load unobtrusively and in real-time.