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In four experiments, we investigated the influence of timbre on perceived interval size. In Experiment 1, musically untrained participants heard two successive tones and rated the pitch distance between them. Tones were separated by six or seven semitones and varied in timbre. Pitch changes were accompanied by a congruent timbre change (e.g., ascending interval involving a shift from a dull to a bright timbre), an incongruent timbre change (e.g., ascending interval involving a shift from a bright to a dull timbre), or no timbre change. Ratings of interval size were strongly influenced by timbre. The six-semitone interval with a congruent timbre change was perceived to be larger than the seven-semitone interval with an incongruent timbre change (interval illusion). Experiment 2 revealed similar effects for musically trained participants. In Experiment 3, participants compared the size of two intervals presented one after the other. Effects of timbre were again observed, including evidence of an interval illusion. Experiment 4 confirmed that timbre manipulations did not distort the perceived pitch of tones. Changes in timbre can expand or contract the perceived size of intervals without distorting individual pitches. We discuss processes underlying interval size perception and their relation to pitch perception mechanisms.

Bottom-up principles of melodic implication (Narmour, 1990) were evaluated in a melody-completion task. One hundred subjects (50 low training; 50 high training in music) were presented each of eight melodic intervals. For each interval, the subjects were asked to compose a short melody on a piano keyboard, treating the interval provided as the first two notes of the melody. For each melody, the first response--the note immediately following the initial interval--was analyzed. Multinomial log linear analyses were conducted to assess the extent to which responses could be predicted by Narmour's (1990, 1992) bottom-up principles. Support was found for all of Narmour's principles, and two additional predictors based on implied tonal structure. Responses of low- and high-training groups were similar.

In four experiments, listeners' sensitivity to combinations of pitch and duration was investigated. Experiments 1-3 involved "textures" of notes, which were created by repeatedly sounding one of two notes (e.g., C4 quarter note; D4 eighth note), so that each note had an equal chance of occurring at any point within a texture. Experiment 1 showed that if a texture change was effected by introducing a pitch or duration that was not in the initial texture, the change was perceived by both attentive and distracted listeners. If a texture change was effected by combining the pitch of one note with the duration of the other note in the initial texture, and vice versa, it was perceived only if the listeners were attentive. Sensitivity to pitch/duration combinations was poorer when the pitch difference between component notes of textures was increased (Experiment 2), but it was better when the difference in duration between component notes was increased (Experiment 3). In Experiment 4, listeners' sensitivity to combinations of pitch pattern and durational pattern in brief sequences was examined. Listeners were sensitive to the manner in which parameter patterns were combined when they were attentive, but not when they were distracted. The results are discussed in view of feature-integration theory and its application to music cognition.

Perceptual relationships between four-voice harmonic sequences and single voices were examined in three experiments. In Experiment 1, listeners rated the extent to which single voices were musically consistent with harmonic sequences. When harmonic sequences did not change key, judgments were influenced by three sources of congruency: melody (whether the single voice was the same as the soprano voice of the harmonic sequence), chord progression (whether the single voice could be harmonized to give rise to the chord progression of the harmonic sequence), and key structure (whether or not the single voice implied modulation). When key changes occurred, sensitivity to sources of congruency was reduced. In Experiment 2, another interpretation of the results was examined: that consistency ratings were based on congruency in well-formedness. Listeners provided well-formedness ratings of the single voices and harmonic sequences. A multiple regression analysis suggested that consistency ratings were based not merely on well-formedness but on congruency in melody, chord progression, and key structure. In Experiment 3, listeners rated the extent of modulation in harmonic sequences and in each voice of the sequences. Discrimination between modulation conditions was greater for single voices than for harmonic sequences, suggesting that abstraction of key from melody may occur without reference to implied harmony. A partially hierarchical system for processing melody, harmony, and key is proposed.