Does the effect of enthusiasm in a pedagogical Agent's voice depend on mental load in the Learner's working memory?

The emotional design hypothesis states that features in digital learning materials can elicit emotional reactions. Voice-related cues, such as enthusiastic accentuations are getting more into the focus of research. These emotion-related cues have to be additionally processed to the relevant instructions while learning, so that the overall amount of to-be-processed information might be a moderator of the effect of emotional cues. One hundred eighteen participants were assigned to one cell of a two (enthusiasm of a pedagogical agent: enthusiastic vs. neutral) × two (mental load in the working memory of the learner: high vs. low) factorial between-subjects design. Regarding the multiple-choice learning test, results revealed that learners with a neutral agent voice performed better in a high load condition, while learners exposed to an enthusiastic voice reached higher learning scores in a low load condition. However, this moderating effect of mental load could not be shown for open answer questions.