Factors that influence the perception of feedback delivered by a pedagogical agent
Three experiments were conducted to assess the relative importance of speech parameters and facial expressions in the delivery of feedback by a pedagogical agent. In Experiment 1, we manipulated linguistic form (i.e., positive, negative, or neutral terms), rate, pitch, pause, and emphasis. In Experiment 2, we manipulated eye size, mouth curve, brow height, and brow curve. In a third study, both speech parameters and facial expressions were manipulated. In all three experiments, the participants were asked to indicate how positive or negative the agent's feedback seemed to be. Across the studies, the variables collectively accounted for a significant amount of the variance. More specifically, the linguistic expressions and mouth curve emerged as significant predictors of the participants' ratings. This suggests that these two features should be implemented by developers wishing to provide appropriate feedback in their pedagogical agents.
International Journal of Speech Technology
Link, K., Kreuz, R., & Graesser, A. (2001). Factors that influence the perception of feedback delivered by a pedagogical agent. International Journal of Speech Technology, 4 (2), 145-153. https://doi.org/10.1023/A:1017383528041