Of particular interest, a number of studies have further linked strain-based differences in discounting with propensity for addictive behavior. For example, rats with a high preference for saccharin have been show to have a propensity for cocaine consumption using a number of indices (e.g., Carroll, Anderson, & Morgan, 2007; Carroll, Morgan, Lynch, Campbell, & Dess, 2002; Perry, Morgan, Anker, Dess, & Carroll, 2006), and also exhibit significantly more impulsive discounting than low-preferring rats (Perry et al., 2007). Similarly, rats and mice from alcohol-preferring strains exhibit significantly greater delay discounting compared to low alcohol preference strains (Oberlin & Grahame, 2009; Wilhelm & Mitchell, 2008). However, this is not the case for all alcohol-preferring strains, as mice in another alcohol-preferring strain, STDRHI2, have not been found to differ compared to STDRL02 mice, a low alcohol preference strain (Wilhelm, Reeves, Phillips, & Mitchell, 2007). In addition, surprisingly, greater impulsivity has been found in DBA/2J mice compared to C57BL/6J mice (Helms, Reeves, & Mitchell, 2006), which is the opposite of what would be predicted by strain-based drug preferences. Although not conclusive at this point,
