Cognitive Meanings of Musical Elements as Disclosed by Event-Related Potential (ERP) and Verbal Experiments

The findings of our experiments on the verbal and ERP responses revealed the interval to be multifaceted and emphasized aspects beyond specific cultural choice. They showed that certain aspects of the harmonic and melodic intervals can be characterized in terms of basic factors contributing to tension or relaxation—in music as well as in speech and even birdcalls (Cohen, 1983). Maximal attention was paid to these factors in the laws of Palestrina counterpoint, which represent a musical ideal of what we can term “calm speech,” and which have extremely strict rules for the selection of events and combinations of events, keeping them within permissible bounds. A substantial portion of the laws—not too much and not too little—are represented by a U curve (which was also found in many parts of our study): the ambitus of each individual part and that among different parts; the lengths of melodies; the degree of change (not too great and not absolute constancy) in pitch, duration, and density; the quantity and density of tension factors, and so on. Despite the limited nature of our material, we found concurrence not only in the principles, but also in the specific manifestation of the intervals (for example, on a melodic interval of an ascending major 6th is forbidden according to the laws of Palestrina counterpoint). Our study did not cover all the laws, but it sheds additional light on some: the requirement to begin and end with perfect consonance; the prohibitions of parallel fifths, dissonance of two simultaneous notes, a melodic interval of an ascending major 6th, and repetition of the same note more than once; the solution of dissonance to perfect consonance; and so on. Thus our findings shed light on the cognitive principles that were presented in the introduction—contrast, U curve, consciousness, and hierarchy. We found contrast to be inherent within melodic and harmonic intervals, between a melodic and a harmonic interval, and between the general parameters of interval and timbre. Characterizing the stimuli by tension factors that follow a U curve or various types of contrast enabled us to set up analogies among harmonic intervals and melodic intervals. It will undoubtedly be possible to expand the analogies to include other musical components and stimuli from other media. The influence of consciousness of the material on the response was determined by comparing subjects with different degrees of consciousness; comparing responses to the same musical material by ERP and verbal report; and by examining the various tasks. The findings concurred with those of other studies (Andrews & Dowling, 1991; Henninger et al., 1989; Wolpert, 1990) in that there proved to be a hierarchy of components in terms of perception, and this hierarchy goes by the degree of abstraction requiring consciousness—a melodic interval, harmonic interval in an immediate context, harmonic interval with no immediate context (other than the harmonic 2nd, which everyone, even those who had never studied music, responded to even with no immediate context or need for a solution). ERP findings that did not concur with the verbal findings pointed to levels of knowledge (latent as opposed to overt). Regarding the task, our findings corroborated those of other studies, but also showed that responses occur even when they relate to a factor other than the task. For example, in the ERP experiment with subject indicating whether reference and comparison intervals were different, the response to a comparison interval that differed from the reference interval would be smaller than that to the reference interval. Furthermore, consciousness of the musical material competed with the task for influence, particularly in the verbal experiments. The ERP findings, including examinations of left/right differences, which concurred interestingly with the other findings, pointed to gradual transitions between the psychoacoustic and cognitive stages and a certain regularity in the connection between the various early and late components and the relationships between amplitude and latency. The occurrence of these stages led to the conjecture that they may represent different factors that contribute to the shaping of the interval: physical factors (which are particularly conspicuous in the harmonic minor 2nd) and psychological factors (sudden change versus no change, difficulty in identification, deviation from expectations, and so on). We have no doubt that, in order to answer all the questions that arose, we must expand the study to include additional phenomena of intervals and other components of the Western and other systems, and other groups of subjects (for example, we should examine the responses of Arabs and Westerners to Arabic material). Already, however, this beginning, aside from the specific findings, points, on the one hand, to the importance of ERP as a complement to the verbal method of studying musical components, and on the other hand, to the interesting complexity of musical components that makes them especially qualified to help us understand brain activity.