Emotional processing modulates attentional capture of irrelevant sound input in adolescents

Abstract

The main goal of this study was to investigate how emotional processing modulates the allocation of attention to irrelevant background sound events in adolescence. We examined the effect of viewing positively and negatively valenced video clips on components of event-related brain potentials (ERPs), while irrelevant sounds were presented to the ears. All sounds evoked the P1, N1, P2, and N2 components. The infrequent, randomly occurring novel environmental sounds evoked the P3a component in all trial types. The main finding was that the P3a component was larger in amplitude when evoked by salient, distracting background sound events when participants were watching negatively charged video clips, compared to when viewing of the positive or neutral video clips. The results suggest that the threshold for involuntary attention to the novel sounds was lowered during viewing of the negative movie contexts. This indicates a survival mechanism, which would be needed for more automatic processing of irrelevant sounds to monitor the unattended environment in situations perceived as more threatening.

Figure 1

Schematic depiction of the stimulus paradigm. Visual (V) and Auditory (A) tracks are presented with simultaneous onsets and offsets. Time scale is represented in seconds (s) on the x-axis. Open rectangles on the audio track depict randomly occurring novel sounds presented amongst pure tones, represented by tick marks. Subject responses are recorded during the 5 s blank screen period.

Figure 2

Event-related brain potentials (ERPs) displayed for the midline Fz (top row), Cz (middle row), and Pz (bottom row) electrodes. ERP responses evoked by the standard tones (left column) and by the novel sounds (right column) are displayed for the Negative (solid line), Positive (dotted line), and Neutral (dashed line) video clip trials. The P1 component is labeled at the Fz electrode in the standard sounds (top row, left column), the P2 component at the Cz electrode (middle row, left column), and the P3a component at the Cz electrode in the difference waveform (middle row, right column), where signal-to-noise ratio is greatest for each respective component. X-axis depicts the time scale in milliseconds. Y-axis depicts microvolts, positive is up.

Figure 3

Difference waveforms are displayed at the Cz electrode, overlaying the P3a components elicited during viewing of the Negative (solid line), Positive (dotted line), and Neutral (dashed line) movie clips. X-axis depicts the time scale in milliseconds. Y-axis depicts microvolts, positive is up. P3a component is labeled.