  Machine learning has typically focused on developing models and algorithms
that would ultimately replace humans at tasks where intelligence is required.
In this work, rather than replacing humans, we focus on unveiling the potential
of machine learning to improve how people learn and remember factual material.
To this end, we perform a large-scale randomized controlled trial with
thousands of learners from a popular learning app in the area of mobility.
After controlling for the length and frequency of study, we find that learners
whose study sessions are optimized using machine learning remember the content
over $\sim$67% longer than those whose study sessions are generated using two
alternative heuristics. Our randomized controlled trial also reveals that the
learners whose study sessions are optimized using machine learning are
$\sim$50% more likely to return to the app within 4-7 days.
