How does the perceived relationship between effort and achievement affect effort? To answer this question, I conduct a field experiment with a popular online learning platform. I exogenously manipulate students' beliefs about returns to effort by assigning them to different information treatments, each of which provides factual information. Students update their beliefs towards the information provided and change their study effort in the same direction with the shifts in their beliefs. This result shows that students' beliefs about the returns to effort is an important component of their human capital accumulation and low-cost information interventions can influence these beliefs.