10 An Expected Musical Note
Listeners' encephalograms have been recorded during song-tune experiments. Enough tune was played for the listener to know what should come next, but the expected note was slightly delayed and then played. The resulting electric pulse or peak resembles the peak recorded when a subject is shown for a second time a picture that was already shown once a few minutes earlier.
In the musical experiment, the two
things that match are something expected and something encountered; in
the other experiment, the two things that match are something remembered
and something encountered. I think that with music, it is fairly definite that
when, note after note, one's expectations keep being met, that is part of what
makes listening a pleasure. So we have here a small clue to how the
matching of two items produces pleasure: some brain-process occurs that gives
that particular kind
of electric pulse. The straight arrow in this
picture represents a process about which almost nothing is known. The Central Idea is
that some process occurs and is felt as pleasure, but this electric pulse
is the nearest we have yet come to tracking it.