Acute psychological stress promotes general alertness and attentional control processes: An ERP study

The current study investigated the influence of acute psychological stress on selective attention processes. After an acute stressor or a control condition, 20 participants performed an arrow-based version of the Eriksen flanker task, while ERPs (N1, N2, P3), reaction times, accuracy, subjective stress, and electrocardiogram signal were measured. Results showed elevated self-report stress, negative affect, state anxiety, heart rate, and reduced high-frequency heart rate variability in the stress block than in the control block, indicating that the flanker task was performed in a stressful situation. In the flanker task, faster response and larger flanker effect of accuracy were observed for the stress block relative to the control block, indicating increased arousal level and improved conflict detection under stress. Event-related potentials locked to target stimuli in the flanker task revealed that (a) frontal N1 was amplified in the stress block than in the control block, indicating elevated vigilance level under stress; (b) frontal N2 was increased in the stress block than in the control block for both congruent and incongruent trials, indicating more intensive attention control under stress; and (c) Increased P3 in the stress block than in the control block may reflect more allocation of neural resources as a consequence of improved attentional control under stress. These findings suggest that acute psychological stress increases general alertness and promotes attentional control in selective attention processes.