An investigation of duplex perception with musical triads.
Duplex perception (DP) occurs when a stimulus simultaneously contributes to the perception
of two auditory events (Rand, 1974), thus violating the principle of exclusive allocation. One
interpretation of DP is that it is the consequence of independent auditory modules
[speech/music vs. acoustical] of which one `mode' [phonetic/musical] has `perceptual
precedence' (Liberman and Mattingly, 1989). The more common scene analysis view is that
DP is the consequence of competing cues for organisation (Bregman, 1987,1990). This thesis
attempted to explore DP with musical triads. It was found that tonal fusion was affected when
triads were presented dichotically. Secondly, these `duplexed' triads evinced a trade-off
between mode and note performance, modulated by presentation (monaural vs. dichotic).
Thirdly, sequential grouping had no effect on DP. Fourthly, the relative timing of the notes in a
chord had little effect on tonal fusion or DP. Finally, there was no evidence for subliminal
tonal fusion, which contradicted the notion of perceptual precedence in DP. Although the
findings support the idea that DP is the product of competing cues (e. g. spatial location vs.
musical schemas), the insensitivity of triads to temporal-sequential organisation highlights
important differences between DP with speech and music.