Terhardt, E., Ward, W.D. (1982). Recognition of musical key: Exploratory study. J. Acoust. Soc. Am. 72, 26-33
The initial 5 s of each of the 12 major-key preludes from J.S. Bach`s Well-Tempered Clavichord was recorded by an expert pianist, either as written or shifted by plus/minus 1, 4, 6, or 7 semitones, and a randomized tape consisting of two repetitions of each of the 108 items was prepared. Twenty musicians, mostly pianists, and two nonmusicians judged whether each item was played in the correct key, transposed up, or transposed down; a simplified version of original (correct) score was printed on the answer sheet. Only four subjects failed to discriminate, at the 5% confidence level, the correct rendition from the transposed ones, even when only plus/minus 1-semitone transpositions are considered. Errors are dependent on the "linear distance" of transposition (i.e., pitch height offset) rather than "harmonic distance" (i.e., offset on the circle of fifths). The subjects claiming to possess absolute pitch performed slightly better than the best of the nonpossessors, but the results suggest that absolute identification of tonality is an ability that is more widespread than commonly supposed.