Caroline B. Monahan

Pitch and Duration as Determinants of Musical Space

In an experiment aimed at assessing dimensional properties of musical space, musicians rated the similarity of pairs of brief melodies on a 9-point scale. From our review of previous work, we hypothesized (1) that pitch variables would be considered more important than time or rhythmic variables by our subjects and (2) that the metrical consonance of pitch and duration patterns would generate a factor related to pattern regularity in listeners9 musical space. Four melodies and their inversions were played in each of four rhythmic patterns (anapestic, dactylic, iambic, and trochaic) for a total of 1024 pattern pairs. Both multidimensional scaling and cluster analyses of similarity showed that at least five dimensions were needed for a good accounting of the perceptual space of these melodies. Surprisingly, the major dimensions found were rhythmic: (1) duple or triple rhythm, (2) accent first or last, and (3) iambic-dactylic versus trochaic-anapestic. Other dimensions were (4) rising or falling pitch and (5) the number of pitch—contour inflections. The tendency to rate patterns on the basis of time or rhythm (Dimensions I, II, and III) was negatively correlated with the tendency to rate patterns on the basis of pitch (Dimensions IV and V). It could not be determined whether this result depends on cognitive processing limitations, attention, or preferences. No factor was found that related to pattern regularity as we defined it.

Studies in auditory timing: 1. Simple patterns

Listeners’ accuracy in discriminating one temporal pattern from another was measured in three psychophysical experiments. When the standard pattern consisted of equally timed (isochronic brief tones, whose interonset intervals (IOIs) were 50, 100, or 200 msec, the accuracy in detecting an asynchrony or deviation of one tone in the sequence was about as would be predicted from older research on the discrimination of single time intervals (6%–8% at an IOI of 200 msec, 11%–12% at an IOI of 100 msec, and almost 20% at an IOI of 50 msec). In a series of 6 or 10 tones, this accuracy was independent of position of delay for IOIs of 100 and 200 msec. At 50 msec, however, accuracy depended on position, being worst in initial positions and best in final positions. When one tone in a series of six has a frequency different from the others, there is some evidence (at IOI = 200 msec) that interval discrimination is relatively poorer for the tone with the different frequency. Similarly, even if all tones have the same frequency but one interval in the series is made twice as long as the others, temporal discrimination is poorer for the tones bordering the longer interval, although this result is dependent on tempo or 101. Results with these temporally more complex patterns may be interpreted in part by applying the relative Weber ratio to the intervals before and after the delayed tone. Alternatively, these experiments may show the influence of accent on the temporal discrimination of individual tones.

The effect of melodic and temporal contour on recognition memory for pitch change

This study was designed to explore the kinds of temporal patterning that foster pitch-difference discrimination. Musicians and nonmusicians rated the similarity of pairs of 9-note melodies that could differ in the pitch chroma of a single note at any of five serial positions. In a complete factorial design, there were 84 standard melodies (4 pitch patterns × 21 rhythms), each of which was paired with 10 octave-raised comparisons; 5 comparisons were identical to the standard in chroma and 5 had a single changed chroma. A literature review suggested that temporal accent occurs for tones initiating a lengthened temporal interval and for tones initiating a group of three or more intervals; pitch-level accent is a product of pitch skips on the order of 4 semitones or of the change of direction of the pitch contour. In this study there were three classes of temporal patterns.Rhythmically, consonant patterns had temporal accenting that was always metrically in phase with pitch-level accenting and promoted the best performance.Rhythmically out-of-phase consonant patterns had temporal accenting and pitch-level accenting that occurred regularly at the same metrical rate, but the two were never in phase. Rhythmically dissonant patterns had temporal accenting and pitch-level accenting at different metrical rates. Patterns in the latter two classes sound syncopated, and they generally resulted in poorer pitch-discrimination performance. Musicians performed better than non musicians on all patterns; however, an account of performance in terms of “rhythmic noncousonance” generated by the above three categories predicted 63% and 42% of the variance in musicians’ and nonmusicians’ performance, respectively. Performance at all serial positions was generally best for tones initiating long sound-filled intervals and was also better at a particular serial position when pitch-level accenting took the form of a pitch contour inflection instead of a unidirectional pitch skip. There was some evidence that rhythmic consonance early in a pattern improved muicians’ performance at a later serial position.

Studies in auditory timing: 2. Rhythm patterns

Listeners discriminated between 6-tone rhythmic patterns that differed only in the delay of the temporal position of one of the tones. On each trial, feedback was given and the subject’s performance determined the amount of delay on the next trial. The 6 tones of the patterns marked off 5 intervals. In the first experiment, patterns comprised 3 “short” and 2 “long” intervals: 12121, 21121, and so forth, where the long (2) was twice the length of a short (1). In the second experiment, patterns were the complements of the patterns in the first experiment and comprised 2 shorts and 3 longs: 21212, 12212, and so forth. Each pattern was tested 45 times (5 positions of the delayed tone × 3 tempos × 3 replications). Consistent with previous work on simple interval discrimination, absolute discrimination (Δt in milliseconds) was poorer the longer the intervals (i.e., the slower the tempo). Measures of relative discrimination (Δt/t,wheret was the short interval, the long interval, or the average of 2 intervals surrounding the delayed tone) were better the slower the tempo. Beyond these global results, large interactions of pattern with position of the delayed tone and tempo suggest that different models of performance are needed to explain behavior at the different tempos. A Weber’s law model fit the slow-tempo data better than did a model based on positions of “natural accent” (Povel & Essens, 1985).

The perceived similarity of auditory polyrhythms

This experiment explored the structural representation of rhythm by having subjects rate the similarity of pairs of polyrhythms. Three different polyrhythms were employed (3×4, 3×5, and 4×5). Although subjects were instructed to ignore pitch, two types of pitch information (pitch proximity and tonal relatedness) were varied between the tones defining the polyrhythms in order to assess their influence on the similarity space of the rhythms. The results showed that, independently of pitch, some rhythm combinations were considered more similar than others. Pitch information had a uniform effect on polyrhythm similarity, systematically increasing or decreasing the similarity among all rhythms by roughly the same amount. This suggests that pitch information may have been processed independently of rhythmic information, and that only at another stage in processing is information from the two dimensions integrated.

Rhythmic and melodic strutures in perceptual space

By asking a person to say how much or how little alike two musical forms are, one can infer the dimensional properties of that persons musical space. We asked musically trained listeners to rate the similarity of pairs of brief melodies on a 9‐point scale. Each of four different melodies and their inversions was played in each of four duration patterns (anapestic, dactylic, iambic, and trochaic) for a total of 1024 pairs of patterns. Multi‐dimensional scaling and cluster analyses of the similarity matrices showed that at least five dimensions were necessary for giving a good account of the perceptual space of these musical structures. Surprisingly, the major dimensions were rhythmic, thus (using INDSCAL): (i) accent early or late, (ii) duple or triple meter, (iii) iambic‐dactylic versus anapestic‐trochaic. Other dimensions were (iv) rising versus falling pitch and (v) number of pitch‐interval reversals. Cluster analysis suggests that some spaces have duple and triple meter as main branches, while others ...

The influence of temporal contour and interval information on the discrimination of rhythmic patterns

Montone rhythmic patterns were constructed, each totaling 16 beats apportioned among 6 notes; we describe the rhythms as ordered sequences of beat interval values of 6 notes, e.g., 313144. Musicians judged similarity of standard‐comparison pattern pairs. On target trials, the comparison had the same rhythm as the standard; on related trials, the comparison had the standards temporal contour, that is, the same series of longs, shorts, and sames without regard to interval size (as in the pair 313144–315133); on lure trials, the comparison had a different contour and intervals. Twenty‐four musicians were randomly assigned to one of three listening conditions that differed in trial types presented: (A) targets versus lures; (B) targest versus relateds, or (C) relateds versus lures. Two other factors were tempo and metrical simplicity (i.e., the extent to which groups of intervals formed simple submultiples of the 16 beats). Discrimination was better (1) in condition A than in B or C, although performance in ...

Discrimination of redundant spectral‐temporal cues. II. Level and duration effects.

The effectiveness of stimulus level and duration on listeners’ ability to attend to and discriminate redundant increments in frequency and duration of pure tones is studied. The stimuli comprised pairs (T1, T2) of 1500‐Hz tone bursts separated by a 60‐ms silent interval. Sensation level was either 66 dB SL for both tones, or one of the tones was attenuated 25 or 40 dB relative to the other 66‐dB SL tone. Tone duration was either 80 ms for both bursts, or T2 was two or three times longer than the 80‐ms T1 burst. In the same three‐interval, 2AFC task described in the above paper, listeners discriminated a ‘‘standard’’ pair of tone bursts from a ‘‘comparison’’ pair containing increments in the duration of T1 and/or in the frequency of T2. Data were obtained for eight highly trained listeners with normal hearing sensitivity. In three listeners, better discrimination performance was obtained for the increment occurring in the louder or longer burst. In four other listeners, tone level and duration had little o...

Discrimination of redundant spectral‐temporal cues. I. Interindividual differences.

Interindividual differences in speech‐processing ability of hearing‐impaired listeners have been attributed to differences in the ability to process residual sets of highly redundant speech cues (e.g., Walden, 1984). This paper describes interindividual differences in listeners’ ability to discriminate redundant increments in the frequency and duration of pure tones. The stimuli comprised pairs (T1, T2) of 1500‐Hz, 80‐ms, 66‐dB SL tones separated by a 60‐ms silent interval [B. Espinoza‐Varas, J. Acoust. Soc. Am. 74, 1687–1694 (1983)]. In a three‐interval, 2AFC task, listeners discriminated a ‘‘standard’’ pair (interval 1) from a ‘‘comparison’’ pair (interval 2 or 3) containing increments in the duration (ΔT) of T1 and/or in the frequency (ΔF) of T2. Discrimination thresholds were interpolated from psychometric functions for ΔT alone, ΔF alone, and combinations of ΔT and ΔF. In highly trained listeners with normal hearing sensitivity (n=8), three main patterns of performance were observed: (a) multicue pro...

Temporal DLs in isochronic loudness and pitch patterns

In an adaptive procedure, listeners discriminated the delay of a single tone in otherwise isochronic six‐tone patterns. The temporal DL was measured at three tempos (isochronic intervals of 50, 100, and 200 ms) and for four delay positions (tones 2–5). In experiment 1, patterns comprised loud (forte) and soft (piano) tones: thus FFPPPF, PFPFPF, etc., where F was 80 dB SPL and P was 70 dB SPL. In experiment 2, frequency patterns were “parallels” of the loudness patterns of the first study: thus HHLLLH, LHLHLH, etc., where H(igh) was 1667 Hz and L(ow) was 1000 Hz. In both studies, the measure of timing accuracy (Weber ratio × 100) was similar to that found in earlier literature for the discrimination of single time intervals, namely, 5%–8% at 200 ms, 9%–15% at 100 ms, and 15%–25% at 50 ms. Accuracy was poorest for early serial positions of the delayed tone. This effect occurred primarily at 50 ms and was significant only in the loudness experiment. In experiment 1, at 50 and 100 ms, accuracy was about 2% be...