2014 Volume 32 Issue 1 Pages 1-10
When a viewer allocates more attention to a video clip, content-unrelated probe stimuli elicit a smaller P3 (P300) component of event-related brain potentials. In the present study, this finding was replicated and extended by calculating correlation coefficients between subjective interest ratings for short video clips and electroencephalographic measures. Fifteen university students watched 12 movie trailers (M=143 s). Meanwhile, a non-painful electric pulse (0.2 ms) was sent to their left middle fingers once every 5 to 7 s, for which a button press with the left thumb was required. After viewing each trailer, participants completed a questionnaire. The composite score of 6 visual analog scales (interesting, attention-getting, like, pleasant, arousing, and want to see the movie) was used as the “interest” score. A stepwise regression analysis showed that both the probe-evoked P3 amplitude (β=-.20) and the occipital alpha-band power during stimulus-absent periods (β=-.29) accounted for the interest score. The results suggest that the single-stimulus electric probe method can be a promising protocol to obtain an objective index of viewers' interest.