Poster #: 78
Topic: MMN across modalities
Friday, Sep 11, 2015
Mismatch negativity for unattended changes in room acoustics is followed by additional negative deflections
Experimental Psychology Unit, Helmut Schmidt University, Hamburg, Germany
Changes in room acoustics provide important clues about the environment of sound source-perceiver systems. Thereby for example, indicating changes in the reflecting characteristics of surrounding objects. In the current study the detection of auditory irregularities brought about by a change in room acoustics, was investigated. Therefore a passive oddball protocol with participants watching a movie (silent with subtitles), was used. Acoustic stimuli with differing room acoustics were presented via headphones as standard and deviant stimuli. Stimuli were created by modelling rooms of different sizes, keeping values of basic auditory dimensions constant, such as pitch, duration, loudness and perceived sound source location. Stimulus duration was 600 msec. In Experiment 1 complex stimuli were used. The stimuli encompassed three short (120 msec) sinusoidal tones, resulting in three onsets peaks during each stimuli. Deviant stimuli elicited a Mismatch Negativity (MMN) and two negative deflections corresponding to the onset peaks. In Experiment 2, stimuli with the same duration (600 msec) and only one sinusoidal tone were used. Again, an MMN was observed for deviant stimuli with different room acoustics. This MMN was followed by an additional negative deflection. These results extend previous work demonstrating the automatic detection of acoustic irregularity brought about by changes in room acoustics. These findings further support the hypothesis that unattended changes in room acoustics elicit a MMN, as well as subsequent negative deflections after these changes are elicited.