Octave generalization and the identification of distorted melodies

Four familiar melodies were distorted in such a way that certain harmonic information was maintained. These melodies and their nondistorted versions were randomly presented to three groups of musically untrained subjects. There were, thus, undistorted melodies which were equal in all ways except the frequencies of the constituent tones, three conditions in which only the octave was maintained, and three other harmonic control conditions in which only the perfect fifth, fourth, and major third were maintained. The melodic sequences were presented to each group using a different tonal waveform for each group: sine wave, rectangular wave, and sawtooth wave. An analysis of variance revealed that the octave distortions were significantly more recognizable than the control conditions. Furthermore, waveform significantly influenced identification of melodies. It was proposed that octave generalization was a major factor in the identification of the distorted octave sequences.     

Tonal strength and melody recognition after long and short delays

In a continuous-running-memory task, subjects heard novel seven-note melodies that were tested after delays of 11 sec (empty) or 39 sec (filled). Test items were transposed to new pitch levels (to moderately distant keys in the musical sense)and included exact transpositions (targets), same-contour lures with altered pitch intervals, and new-contour lures. Melodies differed in tonal strength (degree of conformity to a musical key) and were tonally strong, tonally weak, or atonal. False alarms to same-contour lures decreased over the longer delay period, but only for tonal stimuli. In agreement with previous studies, discrimination of detailed changes in pitch intervals improved with increased delay, whereas discrimination of more global contour information declined, again only for tonal stimuli. These results suggest that poor short-delay performance in rejecting same-contour lures arises from confusion that is based on the similarity of tonality between standard stimuli and lures. If a test item has the same contour and a similar tonality to a just-presented item, subjects tend to accept it. After a delay filled with melodies in other tonalities, the salience of key information recedes, and subjects base their judgments on more detailed pattern information (namely, exact pitch intervals). The fact that tonality affects judgments of melodic contour indicates that contour is not an entirely separable feature of melodies but rather that a melody with its contour constitutes an integrated perceptual whole.     

Tonal strength and melody recognition after long and short delays.

In a continuous-running-memory task, subjects heard novel seven-note melodies that were tested after delays of 11 sec (empty) or 39 sec (filled). Test items were transposed to new pitch levels (to moderately distant keys in the musical sense) and included exact transpositions (targets), same-contour lures with altered pitch intervals, and new-contour lures. Melodies differed in tonal strength (degree of conformity to a musical key) and were tonally strong, tonally weak, or atonal. False alarms to same-contour lures decreased over the longer delay period, but only for tonal stimuli. In agreement with previous studies, discrimination of detailed changes in pitch intervals improved with increased delay, whereas discrimination of more global contour information declined, again only for tonal stimuli. These results suggest that poor short-delay performance in rejecting same-contour lures arises from confusion that is based on the similarity of tonality between standard stimuli and lures. If a test item has the same contour and a similar tonality to a just-presented item, subjects tend to accept it. After a delay filled with melodies in other tonalities, the salience of key information recedes, and subjects base their judgments on more detailed pattern information (namely, exact pitch intervals). The fact that tonality affects judgments of melodic contour indicates that contour is not an entirely separable feature of melodies but rather that a melody with its contour constitutes an integrated perceptual whole.     

An experimental analysis of memory processing

Rhesus monkeys were trained and tested in visual and auditory list-memory tasks with sequences of four travel pictures or four natural/environmental sounds followed by single test items. Acquisitions of the visual list-memory task are presented. Visual recency (last item) memory diminished with retention delay, and primacy (first item) memory strengthened. Capuchin monkeys, pigeons, and humans showed similar visual-memory changes. Rhesus learned an auditory memory task and showed octave generalization for some lists of notes--tonal, but not atonal, musical passages. In contrast with visual list memory, auditory primacy memory diminished with delay and auditory recency memory strengthened. Manipulations of interitem intervals, list length, and item presentation frequency revealed proactive and retroactive inhibition among items of individual auditory lists. Repeating visual items from prior lists produced interference (on nonmatching tests) revealing how far back memory extended. The possibility of using the interference function to separate familiarity vs. recollective memory processing is discussed.     

Maximum key-profile correlation (MKC) as a measure of tonal structure in music

Tonal structure is musical organization on the basis of pitch, in which pitches vary in importance and rate of occurrence according to their relationship to a tonal center. Experiment 1 evaluated the maximum key-profile correlation (MKC), a product of Krumhansl and Schmuckler’s key-finding algorithm (Krumhansl, 1990), as a measure of tonal structure. The MKC is the maximum correlation coefficient between the pitch class distribution in a musical sample and key profiles,which indicate the stability of pitches with respect to particular tonal centers. The MKC values of melodies correlated strongly with listeners’ ratings of tonal structure. To measure the influence of the temporal order of pitches on perceived tonal structure, three measures (fifth span, semitone span, and pitch contour) taken from previous studies of melody perception were also correlated with tonal structure ratings. None of the temporal measures correlated as strongly or as consistently with tonal structure ratings as did the MKC, and nor did combining them with the MKC improve prediction of tonal structure ratings. In Experiment 2, the MKC did not correlate with recognition memory of melodies. However, melodies with very low MKC values were recognized less accurately than melodies with very high MKC values. Although it does not incorporate temporal, rhythmic, or harmonic factors that may influence perceived tonal structure, the MKC can be interpreted as a measure of tonal structure, at least for brief melodies.     

The time course of recognition of novel melodies

Seven experiments explored the time course of recognition of brief novel melodies. In a continuous-running-memory task, subjects recognized melodic transpositions following delays up to 2.0 min. The delays were either empty or filled with other melodies. Test items included exact transpositions (T), same-contour lures (SC) with altered pitch intervals, and different-contour lures (DC). DCs differed from Ts in the pattern of ups and downs of pitch. With this design, we assessed subjects’ discrimination of detailed changes in pitch intervals (T/SC discrimination) as well as their discrimination of contour changes (T/DC). We used both artificial and “real” melodies. Artificial melodies differed in conformity to a musical key, being tonal or atonal. After empty delays, T/DC discrimination was superior to T/SC discrimination. Surprisingly, after filled delays, T/SC discrimination was superior to T/DC. When only filled delays were tested, T/SC discrimination did not decline over the longest delays. T/DC performance declined more than did T/SC performance across both empty and filled delays. Tonality was an important factor only for T/SC discrimination after filled delays. T/DC performance was better with rhythmically intact folk melodies than with artificial isochronous melodies. Although T/SC performance improved over filled delays, it did not overtake T/DC performance. These results suggest that (1) contour and pitch-interval information make different contributions to recognition, with contour dominating performance after brief empty delays and pitch intervals dominating after longer filled delays; (2) a coherent tonality facilitates the encoding of pitch-interval patterns of melodies; and (3) the rich melodic—rhythmic contours of real melodies facilitate T/DC discrimination. These results are discussed in terms of automatic and controlled processing of melodic information.     

Quantification of the hierarchy of tonal functions within a diatonic context

Listeners rated test tones falling in the octave range from middle to high C according to how well each completed a diatonic C major scale played in an adjacent octave just before the final test tone. Ratings were well explained in terms of three factors. The factors were distance in pitch height from the context tones, octave equivalence, and the following hierarchy of tonal functions: tonic tone, other tones of the major triad chord, other tones of a diatonic scale, and the nondiatonic tones. In these ratings, pitch height was more prominent for less musical listeners or with less musical (sinusoidal) tones, whereas octave equivalence and the tonal hierarchy prevailed for musical listeners, especially with harmonically richer tones. Ratings for quarter tones interpolated halfway between the halftone steps of the standard chromatic scale were approximately the averages of ratings for adjacent chromatic tones, suggesting failure to discriminate tones at this fine level of division.     

Auditory feedback in music performance: the role of transition-based similarity

Past research has suggested that the disruptive effect of altered auditory feedback depends on how structurally similar the sequence of feedback events is to the planned sequence of actions. Three experiments pursued one basis for similarity in musical keyboard performance: matches between sequential transitions in spatial targets for movements and the melodic contour of auditory feedback. Trained pianists and musically untrained persons produced simple tonal melodies on a keyboard while hearing feedback sequences that either matched the planned melody or were contour-preserving variations of that melody. Sequence production was disrupted among pianists when feedback events were serially shifted by one event, similarly for shifts of planned melodies and tonal variations but less so for shifts of atonal variations. Nonpianists were less likely to be disrupted by serial shifts of variations but showed similar disruption to pianists for shifts of the planned melody. Thus, transitional properties and tonal schemata may jointly determine perception-action similarity during musical sequence production, and the tendency to generalize from a planned sequence to variations of it may develop with the acquisition of skill.     

The role of knowledge-based expectations in music perception: evidence from musical restoration

The perceptual restoration of musical sounds was investigated in 5 experiments with Samuel's (1981a) discrimination methodology. Restoration in familiar melodies was compared to phonemic restoration in Experiment 1. In the remaining experiments, we examined the effect of expectations (generated by familiarity, predictability, and musical schemata) on musical restoration. We investigated restoration in melodies by comparing familiar and unfamiliar melodies (Experiment 2), as well as unfamiliar melodies varying in tonal and rhythmic predictability (Experiment 3). Expectations based on both familiarity and predictability were found to reduce restoration at the melodic level. Restoration at the submelodic level was investigated with scales and chords in Experiments 4 and 5. At this level, key-based expectations were found to increase restoration. Implications for music perception, as well as similarities between restoration in music and speech, are discussed.     

Culture-general and culture-specific factors in the discrimination of melodies.

We examined effects of a culture-general factor, pattern redundancy (number of repeated tones), on the discrimination of 5-tone melodies that differed in their adherence to Western tonal conventions. Experiment 1 evaluated the ability of 9-month-old infants to differentiate "standard" melodies from subtly altered "comparison" melodies. Greater redundancy of the standard melodies was associated with enhanced infant performance, but musical conventionality had no effect. Experiment 2 evaluated comparable abilities in 5-year-old children and musically untrained adults. Children's performance was enhanced by the redundancy of standard melodies, but the effect was greater in conventional than in unconventional contexts. The redundancy of standard melodies facilitated adults' performance in conventional but not in unconventional contexts. Thus, increasing musical exposure seems to attenuate the effects of culture-general factors such as pattern redundancy while amplifying the influence of culture-specific factors.     

Chickadees fail standardized operant tests for octave equivalence

Octave equivalence occurs when an observer judges notes separated by a doubling in frequency perceptually similar. The octave appears to form the basis of pitch change in all human cultures and thus may be of biological origin. Previously, we developed a nonverbal operant conditioning test of octave generalization and transfer in humans. The results of this testing showed that humans with and without musical training perceive the octave relationship between pitches. Our goal in the current study was to determine whether black-capped chickadees, a North American songbird, perceive octave equivalence. We chose these chickadees because of their reliance on pitch in assessing conspecific vocalizations, our strong background knowledge on their pitch height perception (log-linear perception of frequency), and the phylogenetic disparity between them and humans. Compared to humans, songbirds are highly skilled at using pitch height perception to classify pitches into ranges, independent of the octave. Our results suggest that chickadees used that skill, rather than octave equivalence, to transfer the note-range discrimination from one octave to the next. In contrast, there is evidence that at least some mammals, including humans, do perceive octave equivalence.     

Stimulus-dependent flexibility in non-human auditory pitch processing

Songbirds and humans share many parallels in vocal learning and auditory sequence processing. However, the two groups differ notably in their abilities to recognize acoustic sequences shifted in absolute pitch (pitch height). Whereas humans maintain accurate recognition of words or melodies over large pitch height changes, songbirds are comparatively much poorer at recognizing pitch-shifted tone sequences. This apparent disparity may reflect fundamental differences in the neural mechanisms underlying the representation of sound in songbirds. Alternatively, because non-human studies have used sine-tone stimuli almost exclusively, tolerance to pitch height changes in the context of natural signals may be underestimated. Here, we show that European starlings, a species of songbird, can maintain accurate recognition of the songs of other starlings when the pitch of those songs is shifted by as much as ±40%. We observed accurate recognition even for songs pitch-shifted well outside the range of frequencies used during training, and even though much smaller pitch shifts in conspecific songs are easily detected. With similar training using human piano melodies, recognition of the pitch-shifted melodies is very limited. These results demonstrate that non-human pitch processing is more flexible than previously thought and that the flexibility in pitch processing strategy is stimulus dependent.     

Name or hum that tune: Feeling of knowing for music

This is the first reported research that explores the feeling of knowing (FOK) for musical stimuli. Subjects attempted to recall melodies and titles of musical pieces, made FOK ratings when recall failed, and then had a recognition test. With instrumental music (Experiment 1), more titles were recalled when melodies were given as cues than vice versa. With songs whose lyrics were not presented (Experiment 2), however, more melodies were recalled than were titles. For nonrecalled items, although the overall levels of recognition did not differ, FOK ratings were higher for titles than for melodies in Experiment 1, and the opposite pattern occurred in Experiment 2. In both experiments, the FOK ratings predicted melody recognition more accurately than they did title recognition.     

Representation and execution of vocal motor programs for expert singing of tonal melodies

Three experiments were conducted to study motor programs used by expert singers to produce short tonal melodies. Each experiment involved a response-priming procedure in which singers prepared to sing a primary melody but on 50% of trials had to switch and sing a different (secondary) melody instead. In Experiment 1, secondary melodies in the same key as the primary melody were easier to produce than secondary melodies in a different key. Experiment 2 showed that it was the initial note rather than key per se that affected production of secondary melodies. In Experiment 3, secondary melodies involving exact transpositions were easier to sing than secondary melodies with a different contour than the primary melody. Also, switches between the keys of C and G were easier than those between C and E. Taken together, these results suggest that the initial note of a melody may be the most important element in the motor program, that key is represented in a hierarchical form, and that melodic contour is represented as a series of exact semitone offsets.     

Acomparison of the musical scales of the ancient Chinese bronze bell ensemble and the modern bamboo flute

We compare over a two-octave range the tonal, interval, and scale relationships of an ancient Chinese bell ensemble of the Zhou Dynasty and a modern bamboo flute. By using subjective pitches, a tonal system with simple harmonic partials (the flute) could be compared with a tonal system with complex inharmonic partials (the bell). We argue that the underlying musical scales of the bell ensemble and the flute are closely related and lie between an unequal-interval pure-system scale and the just-intonation scale. There is some evidence that a least interval of 60 or 66 cents figures in the flute scale, that both flute and bell scales include a 90-cent interval and a true (1,200-cent) octave, and that neither scale includes a 100-cent interval. Since there is a true octave, the scales cannot be cycles of fifths, and since there is no equal-temperament half-tone (100 cents), the scales cannot be equal in temperament. We conclude that the flute and Zhou bell scales are very similar if not the same. Apparently, strong cultural traditions and human perceptual constancies united to sustain a common flexible musical scale during 2,400 years.     

Shared musical knowledge in 11‐month‐old infants

Five‐month‐old infants selectively attend to novel people who sing melodies originally learned from a parent, but not melodies learned from a musical toy or from an unfamiliar singing adult, suggesting that music conveys social information to infant listeners. Here, we test this interpretation further in older infants with a more direct measure of social preferences. We randomly assigned 64 11‐month‐old infants to 1–2 weeks’ exposure to one of two novel play songs that a parent either sang or produced by activating a recording inside a toy. Infants then viewed videos of two new people, each singing one song. When the people, now silent, each presented the infant with an object, infants in both conditions preferentially chose the object endorsed by the singer of the familiar song. Nevertheless, infants’ visual attention to that object was predicted by the degree of song exposure only for infants who learned from the singing of a parent. Eleven‐month‐olds thus garner social information from songs, whether learned from singing people or from social play with musical toys, but parental singing has distinctive effects on infants’ responses to new singers. Both findings support the hypothesis that infants endow music with social meaning. These findings raise questions concerning the types of music and behavioral contexts that elicit infants’ social responses to those who share music with them, and they support suggestions concerning the psychological functions of music both in contemporary environments and in the environments in which humans evolved.     

The role of melodic and temporal cues in perceiving musical meter

A number of different cues allow listeners to perceive musical meter. Three experiments examined effects of melodic and temporal accents on perceived meter in excerpts from folk songs scored in 6/8 or 3/4 meter. Participants matched excerpts with 1 of 2 metrical drum accompaniments. Melodic accents included contour change, melodic leaps, registral extreme, melodic repetition, and harmonic rhythm. Two experiments with isochronous melodies showed that contour change and melodic repetition predicted judgments. For longer melodies in the 2nd experiment, variables predicted judgments best at the beginning of excerpts. The final experiment, with rhythmically varied melodies, showed that temporal accents, tempo, and contour change were the strongest predictors of meter. The authors' findings suggest that listeners combine multiple melodic and temporal features to perceive musical meter.     

Acquisition of the hierarchy of tonal functions in music

The acquisition of the hierarchy of tonal stabilities in music is investigated in children of elementary school age. Listeners judge how good short tone sequences sound as melodies. The ratings show a pattern of increasing differentiation of the pitches in an octave range. The youngest listeners distinguish between scale and nonscale tones; older listeners distinguish between the tonic triad tones and other scale components. A group of adult listeners show octave equivalence and temporal asymmetries, with a preference for sequences ending on the more stable tones within the hierarchy. Pitch height effects do not interact with the age of the listener. These results are discussed in terms of the primacy of physical variables, novice-expert differences, and general cognitive principles governing the acquisition and development of internal representations of pitch relationships.     

Perceiving the end: effects of tonal relationships on melodic completion

Two experiments examined listeners' sensitivity to the structural markers of melodic completion. In Experiment 1, both musicians and nonmusicians were asked to rate the ending of folk melodies for their degree of "completeness" and "tonal appropriateness." Results showed that melodies ending with the conventional leading tone-to-tonic progression were rated the most complete and tonally appropriate to the underlying key, more so than melodies ending with the submediant-to-tonic or the tonic-to-dominant progressions. Conversely, melodies ending on the leading tone seemed the most incomplete and tonally inappropriate. In Experiment 2, the perceptual salience of certain pitch functions was enhanced significantly by the pattern of rhythmic accentuation within a melody's context and the presence of the rare tritone interval. The results illustrate an interactive influence of pitch and temporal variables on musical perception and thereby highlight the need to incorporate dynamic pattern factors into internal representations of tonality.     

The influence of height and key on the perceptual similarity of transposed melodies

In two experiments, the perceptual similarity between a strong tonal melody and various transpositions was investigated using a paradigm in which listeners compared the perceptual similarity of a melody and its transposition with that of the same melody and another transposition. The paradigm has the advantage that it provides a direct judgment regarding the similarity of transposed melodies. The experimental results indicate that the perceptual similarity of a strong tonal melody and its transposition is mainly determined by two factors: (1) the distance on the height dimension between the original melody and its transposition (pitch distance), and (2) the distance between keys as inferred from the circle of fifths (key distance). The major part of the variance is explained by the factor pitch distance, whereas key distance explains only a small part.