Steven Pinker -- How the Mind Works - Hampshire High Italian ...

The Meaning of Life 533separating the music into bars. Each bar contains four beats, allocatedamong the different notes, with the first beat getting the strongestemphasis, the third beat an intermediate emphasis, and the second andfourth beats remaining weak. The metrical structure in this example isillustrated by the columns of dots under the notes. Each column correspondsto one tick of a metronome. The more dots in a column, thestronger the accent on that note.The third representation is a reductional structure. It dissects themelody into essential parts and ornaments. The ornaments are strippedoff and the essential parts further dissected into even more essentialparts and ornaments on them. The reduction continues until the melodyis reduced to a bare skeleton of a few prominent notes. Here is "ThisLand" boiled down first to half tones, then to four whole tones, then toonly two whole tones.i^^JJ r ifrTrrJ J irrTrjJriJU JW J J irf ii|* r irrTf J iffT r f NU J J iff i° n• nThe whole passage is basically a fancy way of getting from C to B. Wehear the reductional structure of a melody in the chords of the rhythmguitar line. We also hear it when the band accompanying a tap dancerplays one of the stanzas in stop time, striking a single note in place of anentire line of music so that the tapping is easier to hear. And we sense itwhen we recognize variations of a piece in classical music or jazz. Theskeleton of the melody is conserved while the ornaments differ from variationto variation.Jackendoff and Lerdahl propose that there are in fact two ways thatmelodies may be dissected into simpler and simpler skeletons. I haveshown you the first way, the time-span reduction, which lines up withthe grouping and metrical structures and designates some of the groupsand beats as ornaments on others. Jackendoff and Lerdahl call the secondone a prolongation reduction. It captures the sense of musical flowacross phrases, the buildup and release of tension within longer andlonger passages over the course of the piece, culminating in a feeling of