Online auctions differ from traditional auctions in several ways, but perhaps one of the most significant is the amount of time that bidders interact with the auction mechanism. This paper examines past findings in online auctions and discusses three psychological mechanisms through which bidders may increase their valuations of an item through interaction with the auction mechanism over time. In doing so, this paper provides a theoretical lens through which previous empirical studies of online auctions can be interpreted and serves as a guide for future research.