An important issue that can affect the magnitude of the FRN across a task is whether or not the task involves learning. Müller and colleagues (Müller, Möller, Rodriguez-Fornells, & Münte, 2005) observed that as participants learn the mapping of choices and outcomes, they come to rely less on the external feedback and more on internal error awareness. In their age-based studies, Eppinger et al. (2009) and Hämmerer et al. (2011) speculate that in learning tasks, children show larger FRNs than do older groups due to a greater reliance on external feedback cues as opposed to internal representations of feedback emerging from learning. However, in a chance-based (non-learning) reward feedback task, in a large sample (n = 91), Crowley et al. (in press) observed reductions in FRN magnitude across 10 to 17 years. Thus, age differences in FRN amplitude, which do seem to be reliable, are not necessarily a function of learning. More recently, investigators have begun to look to EEG oscillations associated with reward feedback processing (Cavanagh, Frank, Klein, & Allen, 2010; Cavanagh, Zambrano-Vazquez, & Allen, 2012; Cohen, Elger, & Ranganath, 2007), but only in adult samples.
