Recognition of durations embedded in temporal patterns

Differential short-term memorisation for vocal and instrumental rhythms

This study explores differential processing of vocal and instrumental rhythms in short-term memory with three decision (same/different judgments) and one reproduction experiment. In the first experiment, memory performance declined for delayed versus immediate recall, with accuracy for the two rhythms being affected differently: Musicians performed better than non-musicians on clapstick but not on vocal rhythms, and musicians were better on vocal rhythms in the same than in the different condition. Results for the second experiment showed that concurrent sub-vocal articulation and finger-tapping differentially affected the two rhythms and same/different decisions, but produced no evidence for articulatory loop involvement in delayed decision tasks. In a third experiment, which tested rhythm reproduction, concurrent sub-vocal articulation decreased memory performance, with a stronger deleterious effect on the reproduction of vocal than of clapstick rhythms. This suggests that the articulatory loop may only be involved in delayed reproduction not in decision tasks. The fourth experiment tested whether differences between filled and empty rhythms (continuous vs. discontinuous sounds) can explain the different memorisation of vocal and clapstick rhythms. Though significant differences were found for empty and filled instrumental rhythms, the differences between vocal and clapstick can only be explained by considering additional voice specific features.

Release from Retroactive Retention Interference for Acoustic Duration

Listener retention of stimulus duration was studied. Measures of difference-limen-for-duration (DLD) between standard and comparison stimuli were obtained for intervals with and without intervening noise bursts, including an intervening condition with a lateralization cue. The DLD was significantly higher when intervening sounds were present, but a lateralization cue mitigated the interference, presumably by allowing attention to be more readily allocated to retention of the standard. General interference results are in keeping with those reported for pitch, loudness, and timbre retention, but not for retention of gap length. Release from interference with a lateralization cue is akin to that reported for pitch. Overall, the ramifications of retroactive interference on duration retention are more similar to those reported for pitch than for another temporal-based attribute—namely, gap length.

To the beat of your own drum: cortical regularization of non-integer ratio rhythms toward metrical patterns

Humans perceive a wide range of temporal patterns, including those rhythms that occur in music, speech, and movement; however, there are constraints on the rhythmic patterns that we can represent. Past research has shown that sequences in which sounds occur regularly at non-metrical locations in a repeating beat period (non-integer ratio subdivisions of the beat, e.g. sounds at 430ms in a 1000ms beat) are represented less accurately than sequences with metrical relationships, where events occur at even subdivisions of the beat (integer ratios, e.g. sounds at 500ms in a 1000ms beat). Why do non-integer ratio rhythms present cognitive challenges? An emerging theory is that non-integer ratio sequences are represented incorrectly, "regularized" in the direction of the nearest metrical pattern, and the present study sought evidence of such perceptual regularization toward integer ratio relationships. Participants listened to metrical and non-metrical rhythmic auditory sequences during electroencephalogram recording, and sounds were pseudorandomly omitted from the stimulus sequence. Cortical responses to these omissions (omission elicited potentials; OEPs) were used to estimate the timing of expectations for omitted sounds in integer ratio and non-integer ratio locations. OEP amplitude and onset latency measures indicated that expectations for non-integer ratio sequences are distorted toward the nearest metrical location in the rhythmic period. These top-down effects demonstrate metrical regularization in a purely perceptual context, and provide support for dynamical accounts of rhythm perception.

Dissociation of duration-based and beat-based auditory timing in cerebellar degeneration

This work tests the hypothesis that the cerebellum is critical to the perception of the timing of sensory events. Auditory tasks were used to assess two types of timing in a group of patients with a stereotyped specific degeneration of the cerebellum: the analysis of single time intervals requiring absolute measurements of time, and the holistic analysis of rhythmic patterns based on relative measures of time using an underlying regular beat. The data support a specific role for the cerebellum only in the absolute timing of single subsecond intervals but not in the relative timing of rhythmic sequences with a regular beat. The findings support the existence of a stopwatch-like cerebellar timing mechanism for absolute intervals that is distinct from mechanisms for entrainment with a regular beat.

Relative priming of temporal local--global levels in auditory hierarchical stimuli

Priming is a useful tool for ascertaining the circumstances under which previous experiences influence behavior. Previously, using hierarchical stimuli, we demonstrated (Justus & List, 2005) that selectively attending to one temporal scale of an auditory stimulus improved subsequent attention to a repeated (vs. changed) temporal scale; that is, we demonstrated intertrial auditory temporal level priming. Here, we have extended those results to address whether level priming relied on absolute or relative temporal information. Both relative and absolute temporal information are important in auditory perception: Speech and music can be recognized over various temporal scales but become uninterpretable to a listener when presented too quickly or slowly. We first confirmed that temporal level priming generalized over new temporal scales. Second, in the context of multiple temporal scales, we found that temporal level priming operates predominantly on the basis of relative, rather than absolute, temporal information. These findings are discussed in the context of expectancies and relational invariance in audition.

Metricality-enhanced temporal encoding and the subjective perception of rhythmic sequences

Feeling the beat of a musical piece is easier for some pieces than others, depending on the underlying metrical structure. The present study sought to determine whether increasing metricality, meaning the amount of information supporting an intended meter, would elicit a corresponding increase in the precision of the temporal encoding of rhythmic sequences. Metricality was varied i) by using the Povel and Essens (1985) model of temporal accent induction to create a strong or weak sense of meter and ii) by including metrically plausible (compact) or implausible (open) endings. Precision of temporal encoding as a function of degree of metricality was assessed in an adaptively controlled change detection task. The change to be detected was a perturbation of relative interval timing that affected sequences as a whole rather than at specific points only. Change detection thresholds were significantly lower for sequences featuring a strong compared to a weak meter, and a compact compared to an open ending. Subjective ratings of rhythmicality of sequences also yielded main effects of strength of meter and ending. The data support an increase in the precision of temporal pattern encoding for sequences with a higher-order metrical time framework.

Limits of rhythm perception

To what extent are listeners sensitive to the time intervals separating non-consecutive events in sound sequences? The subjects of Experiment 1 were presented with sequences of 20 identical tones in which the 10 odd-numbered tones or the 10 even-numbered tones made up an isochronous sub-sequence (with a periodicity of 0.5-1 s) whereas the other tones, acting as distractors, occurred at random moments. Such sequences appeared to be very difficult to discriminate from sequences without any timing regularity, which revealed a lack of perceptual sensitivity to their "second-order" intervals. Experiment 2 employed repetitive sequences in which the first-order intervals (separating consecutive tones) took two possible values, forming a ratio that subjects had to classify as larger or smaller than 2. The results of this experiment suggest that subjects were able to make use of second-order intervals in their task, but mainly due to the predictable nature of the sequences; the relative positions of subjective accents (Povel & Essens, 1985) had no significant effect on performance. It is concluded that the perception of subtle timing details in "ordinary" music may rest on nothing more than a sensitivity to the relations between first-order intervals (within a given auditory stream).

Rhythm and pitch in music cognition

Rhythm and pitch are the 2 primary dimensions of music. They are interesting psychologically because simple, well-defined units combine to form highly complex and varied patterns. This article brings together the major developments in research on how these dimensions are perceived and remembered, beginning with psychophysical results on time and pitch perception. Progressively larger units are considered, moving from basic psychological categories of temporal and frequency ratios, to pulse and scale, to metrical and tonal hierarchies, to the formation of musical rhythms and melodies, and finally to the cognitive representation of large-scale musical form. Interactions between the dimensions are considered, and major theoretical proposals are described. The article identifies various links between musical structure and perceptual and cognitive processes, suggesting psychological influences on how sounds are patterned in music.

Interference effects in short-term memory for timbre

Four experiments investigated memory for timbre using the interpolated-tone paradigm [Deutsch, Science 168, 1604-1605 (1970)], in which participants discriminate pairs of tones (standard and comparison) separated by intervening (interpolated) tones. Interpolated tones varied from the standard tone in spectral similarity (within-dimensional variation), fundamental frequency (cross-dimensional variation), and repetition frequency. While the latter two variables had negligible effects on timbre memory, interference with timbre memory increased with the spectral similarity of the interpolated tones to the standard tone. The findings closely parallel those found for pitch memory, and suggest that memory interference depends on perceptual similarity in both cases.

Temporal coding in rhythm tasks revealed by modality effects

Temporal coding has been studied by examining the perception and reproduction of rhythms and by examining memory for the order of events in a list. We attempt to link these research programs both empirically and theoretically. Glenberg and Swanson (1986) proposed that the superior recall of auditory material, compared with visual material, reflects more accurate temporal coding for the auditory material. In this paper, we demonstrate that a similar modality effect can be produced in a rhythm task. Auditory rhythms composed of stimuli of two durations are reproduced more accurately than are visual rhythms. Furthermore, it appears that the auditory superiority reflects enhanced chunking of the auditory material rather than better identification of durations.

Ratio judgments of empty durations with numeric scales

A study is reported on the perception of empty time intervals marked by auditory signals. Nakajima's supplement hypothesis, which states that the subjective duration of a subjectively empty time interval is proportional to its physical duration plus a constant of approximately 80 ms, was examined quantitatively. Although this hypothesis has been used to explain various general aspects of time perception, from a global viewpoint, it has lacked the quantitative data necessary to describe the shape of the psychophysical functions mathematically. In the present study, subjects used two positive numbers to estimate the subjective ratio (m:n) between the durations of two serial or separate empty intervals. The psychophysical functions for empty durations 50-600 ms long could be approximated by a straight line with a positive gamma-intercept, as predicted by the hypothesis. The effective range of the hypothesis could be extended to approximately 1200 ms. A power function (without any modifications) also gave good approximations. The reliability and validity of the supplement hypothesis are discussed.