Recently, findings have emerged in the neuroimaging and electroencephalogram (EEG) literatures on reward processing suggesting that sex should be considered as an important source of variability (Kamarajan et al., 2008). Such differences may arise, for example, as a function of reward type/context (social vs. non-social, Spreckelmeyer et al., 2009), with reward circuitry in males significantly more engaged by video game–like tasks than females (Hoeft, Watson, Kesler, Bettinger, & Reiss, 2008). Moreover, mental disorders for which reward processing is a core aspect, such as ADHD and depression, have marked sex differences in prevalence, emerging in childhood and early adolescence respectively (Kessler, McGonagle, Swartz, Blazer, & Nelson, 1993; Waddell & McCarthy, 2010). Recently, in a sample of at-risk 15-year-olds, we reported that ERP responses in males differentiated more between the reward and loss conditions than in the females (Crowley et al., 2009). The effect of differential response to feedback (loss vs. reward) was over twice as large for males, although this finding emerged in a high-risk sample and may not generalize to low-risk youth. On the other hand,Santesso et al. (2011) reported
