In this demonstration, a 500-Hz tone of one second duration alternates with another tone that varies from 985 to 1035 Hz in steps of 5 Hz. Which one sounds like a correct octave? Most listeners will probably select a tone somewhere around 1010 Hz.
D.Allen (1967), "Octave discriminibility of musical and non-musical subjects," Psychonomic Sci. 7, 421-22.
E.M.Burns and W.D.Ward (1982), "Intervals, scales, and tuning," in The Psychology of Music, ed. D.Deutsch (Academic Press, New York) pp. 241-69.
J.E.F.Sundberg and J.Lindqvist (1973), "Musical octaves and pitch," J. Acoust. . Soc. Am. 54, 922-29.
W.D.Ward (1954), "Subjective musical pitch," J. Acoust. Soc. Am. 26, 369-80.