Attention to Television: Alpha Power and Its Relationship to Image Motion and Emotional Content

Abstract

A laboratory experiment investigated the impact of image motion and emotional content in brief television clips on attention. Using an electroencephalogram (EEG) as a measure of attention, cortical activity in 25 participants was measured while they viewed either still or moving emotion-provoking images. Spectral analysis of the EEG was done to gauge changes in alpha-wave (8-13 Hz) power because reductions in alpha power are thought to indicate greater attention. The analysis revealed that subjective reports of emotional arousal were directly related to cortical activation (i.e., reduced alpha power), and this was particularly true at the parietal recording site. The relationship between alpha power and ratings of valence was curvilinear; cortical activation was associated with both positive and negative images relative to neutral images. Alpha power was also reduced during the viewing of moving compared with still images, and this effect occurred independent of stimulus valence. The association of greater cortical activation with moving than with still images is consistent with previous research using autonomic measures and suggests that image motion modulates emotional responding-and sustains attention-primarily through increasing "gain" in the arousal dimension.