Data were off-line referenced to mathematically linked mastoids. Because we were interested in FRN as well as in P300, EEG data were filtered offline with different parameters, which is in line with previous literature (Luu et al. 2003; Donkers et al. 2005; Wu and Zhou 2009). For the FRN, data were filtered using a 2 to 12 Hz bandpass filter (Donkers et al. 2005). A conventional wideband filter of 0.10 to 30 Hz (phase shift-free Butterworth filters; 24 dB/octave slope) was used to investigate the feedback related P300 amplitude. After ocular correction (Gratton et al. 1983), feedback-locked epochs were created from positive (balloon inflated; money gained) and negative (balloon popped; money lost) feedback and were baseline corrected using the 200-ms pre-stimulus interval. The length of the epochs was 1,000 ms (200 ms pre-stimulus until 800 ms post-stimulus). Epochs including out of range voltages (±75 μV) were rejected as artifacts and were excluded from further processing. If 50% or more of the epochs of a participant contained artifacts, this participant was excluded from further analyses. As a result, three participants were
