Researchers at Stanford University looked at how early and repeated exposure to examples affects creativity. Their findings suggest that early exposure to examples improves creativity, however late exposure to examples does not improve creativity and increases conformity. In addition, the exposure to examples in general reduced the quantity of the creative output.
See:
Kulkarni, C., Dow, S.P., Klemmer,S.R. (2012) Early and Repeated Exposure to Examples Improves Creative Work, Cognitive Science.