  Conversational Task Assistants (CTAs) guide users in performing a multitude
of activities, such as making recipes. However, ensuring that interactions
remain engaging, interesting, and enjoyable for CTA users is not trivial,
especially for time-consuming or challenging tasks. Grounded in psychological
theories of human interest, we propose to engage users with contextual and
interesting statements or facts during interactions with a multi-modal CTA, to
reduce fatigue and task abandonment before a task is complete. To
operationalize this idea, we train a high-performing classifier (82% F1-score)
to automatically identify relevant and interesting facts for users. We use it
to create an annotated dataset of task-specific interesting facts for the
domain of cooking. Finally, we design and validate a dialogue policy to
incorporate the identified relevant and interesting facts into a conversation,
to improve user engagement and task completion. Live testing on a leading
multi-modal voice assistant shows that 66% of the presented facts were received
positively, leading to a 40% gain in the user satisfaction rating, and a 37%
increase in conversation length. These findings emphasize that strategically
incorporating interesting facts into the CTA experience can promote real-world
user participation for guided task interactions.
