Satisfactory human performance demands the complex interaction of multiple factors such as arousal/motivation, emotion expression and regulation, intricate synchronization of central and peripheral motor processes, all recruited in the service of adaptive, moment to moment decision making. The segregation of these various factors aids in the understanding of their complex interactions. Recently, scientific investigation has focused on understanding the integration of these various factors. The complementary role of emotion and cognition in successful human performance is emphasized. As a viable metric of emotion regulation differences in asymmetry of human brain frontal activity have traditionally been utilized to index certain trait predispositions within the approach/withdrawal dimension of emotion/motivation. Researchers have begun to make a case for an acute or state difference in frontal asymmetry. This "Capability Model" posits the neural underpinnings of the relative difference in electrical activity between the left and right frontal lobes as a phasic/situational mechanism possibly sub-serving the integration of emotion and cognition during challenge. The current study demonstrates support for this situational/state model of frontal asymmetry. Thirty channels of EEG were collected along with, skin conductance, heart rate and acoustic startle amplitudes while subjects were engaged in two levels of a working memory task under three increasing levels of stress (final level=electric stimuli/shock). Hierarchical regression results implicate state frontal asymmetry differences as having a mediating role in the adaptive regulation of emotion during enhanced performance on an N-back working memory task but only in the high stress condition. During shock /threat of shock participants with higher state asymmetry scores showed significant attenuation of eye-blink startle magnitudes, faster reaction times and increased accuracy. This suggests an integration of emotion and cognition.