Evaluating cognitive load in spoken language interfaces using a dual-task paradigm

As speech interfaces become more prevalent, it i s becoming more crucial that they be developed in a way that minimizes cognitive load for users. One major barrier to creating systems that are more human-centered has been the lack of an accepted online methodology for directly evaluating the cognitive resource demands of different systems. The present study extends a classic tool from cognitive psychology, the dual-task paradigm, to speech interface evaluation. Participants follow simple instructions generated by a system, while simultaneously monitoring for a simple visual probe. Performance on the monitoring task is used as a measure of cognitive resource demands; whenever language understanding is more demanding, performance on the monitoring task suffers. In the present study we used this methodology to investigate patterns of reference generation and how they impact human understanding.