EMOTIONAL VALENCE AND PSYCHOACOUSTICS OF IRRELEVANT SPEECH
AbstractTo investigate whether the emotional valence of irrelevant speech has an influence on the disruption of memory performance, two variables were independently manipulated: (1) the semantic content of the background speech which consisted of lists of positive, neutral, or negative words, and (2) the prosody imposed by recording the word lists in either a happy, a neutral, or an angry voice. Fourty participants were exposed to the resulting nine combinations of background speech conditions while performing a serial-recall task. All irrelevant-speech stimuli impaired memory perfomance when compared to a white-noise control condition. Semantic content did not differentially affect performance, though, while prosody did in that the recordings made in an angry voice produced significantly lower recall scores than the recordings made in a happy or neutral voice. To investigate whether sound features may be identified that carry the crucial prosody information, psychoacoustic analyses of the irrelevant-speech recordings were performed. It turned out that psychoacoustical 'fluctuation strength' - the magnitude of amplitude and frequency modulations present in the signals - predicted the overall pattern of performance quite well.