Subtitled videos and mismatch negativity (MMN) investigations of spoken word processing

The purpose of this study was to determine whether the presence of subtitles on a distracting, silent video affects the automatic mismatch negativity (MMN) response to simple tones, consonant-vowel (CV) nonwords, or CV words. Two experiments were conducted in this study, each including ten healthy young adult subjects. Experiment 1 investigated the effects of subtitles on the MMN response to simple tones (differing in frequency, duration, and intensity) and speech stimuli (CV nonwords and CV words with a /d/-/g/ contrast). Experiment 2 investigated the effects of subtitles on the MMN response to a variety of CV nonword and word contrasts that incorporated both small (e.g., /d/ vs. /g/) and/or large (e.g., /e:/ vs. /el/) acoustic deviances. The results indicated that the presence or absence of subtitles on the distracting silent video had no effect on the amplitude of the MMN or P3a responses to simple tones, CV nonwords, or CV words. In addition, the results also indicated that movement artifacts may be statistically reduced by the presence of subtitles on a distracting silent video. The implications of these results are that more "engaging" (i.e., subtitled) silent videos can be used as a distraction task for investigations into MMN responses to speech and nonspeech stimuli in young adult subjects, without affecting the amplitude of the responses.