group during the approach condition (AVG: p < .05 and d = .28; Cz: p < .05 and d = .29; LM: p < .05 and d = .29) and the withdrawal condition (AVG: p < .001 and d = .45; Cz: p < .001 and d = .50; LM: p < .01 and d = .46) but not the rest condition for Cz or LM (both p > .52). Although the groups differed during the rest condition for AVG (p < .01 and d = .12) the pattern of means was in the unpredicted direction, with the lifetime MDD+ group exhibiting higher relative left frontal activity than the lifetime MDD− group. Biological sex did not moderate lifetime MDD by condition results for any reference (all p > .60). In summary, findings for three out of four reference modes supported the capability model of EEG asymmetry, which asserts that state emotion challenges will be more powerful in detecting individual differences than resting sessions. In contrast, findings indicate that CSD–transformed frontal EEG alpha asymmetry at rest may be robust marker of risk for depression (see Stewart, Bismark, et al, 2010).
