“…For example, increased food deprivation has been consistently shown to increase drug and ethanol self-administration (Carr, 1996; Carroll & Boe, 1984; Carroll, Stotz, Kliner, & Meisch, 1984; Kliner & Meisch, 1989; Meisch & Lemaire, 1991). Unlike food deprivation, the availability of alternative non-drug reinforcements such as sucrose or food can either increase (Shahan & Burke, 2004; Weatherly, Bishop, & Borowiak, 2004; Winsauer & Thompson, 1991) or decrease drug self-administration, particularly under schedules of reinforcement that operate concurrently (Campbell & Carroll, 2000; Carroll, Rodefer, & Rawleigh, 1995; Cosgrove & Carroll, 2003; Samson, Roehrs, & Tolliver, 1982). …”