Mozart Sharpens and Mahler Degrades the Word Memory Trace

We investigated the impact of the Mozart effect on word memory when music was heard in the delay rather than using music to induce mood or as background music. A sample of N = 84 participants was randomly assigned to one of three groups listening to a one-minute sound clip of Mozart (*Kleine Nachtmusik*) or Mahler (*Adagietto*) during the delay, with a third control group waiting in silence for the word memory test. Words were positive, negative or neutral and matched for word length and frequency. The word memory task was repeated three times (enforced rehearsal). Word memory was best after Mozart and worst after Mahler, with memory performance in the control condition in between. The Mozart effect occurred for word memory across positive, negative and neutral words. The Mozart effect also occurred independently of ethnicity, or the level of happiness in the participants. We conclude that word memory traces sharpened after Mozart’s music because the sonogram and spectrograms showed that this music had self-contained and bounded phrases like in psycholinguistic structures of words and sentences. In contrast, word memory traces may have washed out and degraded during the delay because Mahler’s music was flowing like a foreign language speech stream where a native speaker would not be able to parse words.