Artificial intelligence may be booming, but there are some things people can still do better.

That’s according to a new study from the University of British Columbia’s Sauder School of Business, which found that virtual salespeople in livestreams don’t outperform humans in the same role. In fact, when interacting with consumers to promote products in real time, these AI-powered “digital streamers” barely do better than no streamers at all. (So much for AI coming for that job.)

“People assume that if businesses are using digital streamers, they must be doing well,” said Yanwen Wang, coauthor of the study. “But they aren’t, at least not in their current incarnation.”

The study, published in Information Systems Research, looked at sales data from e-commerce site Tmall.com. It compared sales by humans and AI-powered digital streamers of 328 products (74 by humans, 72 by digital streamers, and 182 with no streamers).

While the results were clear that sales were much higher when actual people were involved, the question of why remained.

By testing AI streamers that looked and sounded different, study researchers found more realistic avatars—which behaved more like humans, with more human-sounding voices—made a real difference in what people bought.

In fact, one key factor made the most difference: The avatar’s ability to answer questions in real time increased sales by 25%, for an 86% rise in revenue. (That’s not all: Surprisingly, adding a lottery to the livestream—where viewers could win prizes—helped increase sales by another 17%, boosting revenue 70%.)

“Only enhanced real-time Q&A interactions allowed the digital streamers to achieve sales performances on par with human streamers,” Wang concluded, suggesting quicker, interactive engagement is a key driver of sales, and that the best approach to selling online may be a mix of human and AI elements.