Barbara Tillmann

Activation of the inferior frontal cortex in musical priming.

Musical contexts influence the processing of target events. Our study investigated the neural correlates of processing related and unrelated musical events presented as the last chord of eight-chord sequences.

Listening to polyphonic music recruits domain-general attention and working memory circuits

Polyphonic music combines multiple auditory streams to create complex auditory scenes, thus providing a tool for investigating the neural mechanisms that orient attention in natural auditory contexts. Across two fMRI experiments, we varied stimuli and task demands in order to identify the cortical areas that are activated during attentive listening to real music. In individual experiments and in a conjunction analysis of the two experiments, we found bilateral blood oxygen level dependent (BOLD) signal increases in temporal (the superior temporal gyrus), parietal (the intraparietal sulcus), and frontal (the precentral sulcus, the inferior frontal sulcus and gyrus, and the frontal operculum) areas during selective and global listening, as compared with passive rest without musical stimulation. Direct comparisons of the listening conditions showed significant differences between attending to single timbres (instruments) and attending across multiple instruments, although the patterns that were observed depended on the relative demands of the tasks being compared. The overall pattern of BOLD signal increases indicated that attentive listening to music recruits neural circuits underlying multiple forms of working memory, attention, semantic processing, target detection, and motor imagery. Thus, attentive listening to music appears to be enabled by areas that serve general functions, rather than by music-specific cortical modules.

The effect of harmonic context on phoneme monitoring in vocal music

The processing of a target chord depends on the previous musical context in which it has appeared. This harmonic priming effect occurs for fine syntactic-like changes in context and is observed irrespective of the extent of participants musical expertise (Bigand & Pineau, Perception and Psychophysics, 59 (1997) 1098). The present study investigates how the harmonic context influences the processing of phonemes in vocal music. Eight-chord sequences were presented to participants. The four notes of each chord were played with synthetic phonemes and participants were required to quickly decide whether the last chord (the target) was sung on a syllable containing the phoneme /i/ or /u/. The musical relationship of the target chord to the previous context was manipulated so that the target chord acted as a referential tonic chord or as a congruent but less structurally important subdominant chord. Phoneme monitoring was faster for the tonic chord than for the subdominant chord. This finding has several implications for music cognition and speech perception. It also suggests that musical and phonemic processing interact at some stage of processing.

Sensory versus cognitive components in harmonic priming.

This study investigated the strength of sensory and cognitive components involved in musical priming. In Experiment 1, the harmonic function of the target chord and the number of pitch classes shared by the prime sequence and the target chord were manipulated. In Experiment 2, the temporal course of sensory and cognitive priming was investigated. For both musician and nonmusician listeners, cognitive priming systematically overruled sensory priming even at fast and very fast tempi (300 ms and 150 ms per chord). Cognitive priming continued to challenge sensory priming processes at extremely fast tempo (75 ms per chord) but only for participants who began the experimental session with slower tempi. This outcome suggests that the cognitive component is a fast-acting component that competes with sensory priming.

Implicit Learning of Musical Timbre Sequences: Statistical Regularities Confronted With Acoustical (Dis)Similarities.

The present study investigated the influence of acoustical characteristics on the implicit learning of statistical regularities (transition probabilities) in sequences of musical timbres. The sequences were constructed in such a way that the acoustical dissimilarities between timbres potentially created segmentations that either supported (S1) or contradicted (S2) the statistical regularities or were neutral (S3). In the learning group, participants first listened to the continuous timbre sequence and then had to distinguish statistical units from new units. In comparison to a control group without the exposition phase, no interaction between sequence type and amount of learning was observed: Performance increased by the same amount for the three sequences. In addition, performance reflected an overall preference for acoustically similar timbre units. The present outcome extends previous data from the domain of implicit learning to complex nonverbal auditory material. It further suggests that listeners become sensitive to statistical regularities despite acoustical characteristics in the material that potentially affect grouping.

The Costs and Benefits of Tonal Centers for Chord Processing

Harmonic priming studies have shown that a musical context, with its established tonal center, influences target chord processing. This study investigated costs and benefits of priming tonal centers for target processing by adding a baseline condition (sequences without a specific tonal center). Results confirmed harmonic priming, with faster processing for related than for unrelated and less related targets (tonic chord, out-of-key chord, subdominant chord). Comparing targets in baseline contexts with targets in sequences with well-established tonal centers revealed a benefit of processing for related targets but a cost of processing for unrelated and less related targets. Findings are discussed in terns of tonal knowledge activation and suggest that an activated tonal center gives rise to strong expectations for the tonic.

Global context effect in normal and scrambled musical sequences

The processing of chords is facilitated when they are harmonically related to the context in which they appear. The purpose of this study was to assess whether this harmonic priming effect depends on the version (normal vs. scrambled) of the context chord sequences. Normal sequences were scrambled by permuting chords two-by-two (Experiment 1) or four-by-four (Experiments 2 and 3). Normal chord sequences were judged less coherent than scrambled sequences. However, normal chord sequences showed facilitation for harmonically related rather than for unrelated targets, and this effect of relatedness did not diminish for scrambled sequences (Experiments 1-3). The data of musicians and nonmusicians were interpreted with Bharuchas (1987) spreading activation framework. Simulations suggested that harmonic priming results from activation that spreads via schematic knowledge of Western harmony and accumulates in short-term memory over the course of the chord sequence.

Effect of harmonic relatedness on the detection of temporal asynchronies

Speeded intonation judgments of a target chord are facilitated when the chord is preceded by a harmonically related prime chord. The present study extends harmonic priming to temporal asynchrony judgments. In both tasks, the normative target chords (consonant, synchronous) are processed more quickly and accurately after a harmonically related prime than after a harmonically unrelated prime. However, the influence of harmonic context on sensitivity (d) differs between the two tasks:d was higher in the related context for intonation judgments but was higher in the unrelated context for asynchrony judgments. A neural net model of tonal knowledge activation provides an explanatory framework for both the facilitation in the related contexts and the sensitivity differences between the tasks.

Implicit Learning of Regularities in Western Tonal Music by Self-Organization

Western tonal music is a highly structured system whose regularities are implicitly learned in everyday life. A hierarchical self-organizing network simulates learning of tonal regularities by mere exposure to musical material. The trained network provides a parsimonious account of empirical findings on perceived tone, chord and key relationships and suggests activation as a unifying mechanism underlying a range of cognitive tasks.