Students study more in college if their roommates and friends are more studious. Not a surprising result.

Time-Use and Academic Peer Effects in College
by Nirav Mehta, Ralph Stinebrickner, Todd Stinebrickner - #25168
(ED)
NBER
Abstract:
This paper examines academic peer effects in college. Unique new
data from the Berea Panel Study allow us to focus on a mechanism
wherein a student's peers affect her achievement by changing her
study effort. Although the potential relevance of this mechanism
has been recognized, data limitations have made it difficult to
provide direct evidence about its importance. We find that a
student's freshman grade point average is affected by the amount
her peers studied in high school, suggesting the importance of
this mechanism. Using time diary information, we confirm that
college study time is actually being affected.