Consonant Chords Research Articles

The ripples of consonant intervals and chords arising in different tuning systems

Pure consonances are combinations of exact multiples of a fundamental frequency, particularly with the factors 2, 3, and 5. They give rise to the consonant intervals (octave, perfect fifth, and major and minor thirds) and consonant chords (major and minor). However, these kinds of consonances are only achieved in just intonation, which does not produce beats or ripples, that is, their envelopes are constant. On the contrary, other tuning systems, such as Pythagorean, meantone, or N-tone equal temperaments, which slightly differ from just intonation, actually produce beats or ripples, that is, the corresponding envelopes oscillate and, acoustically, resemble a vibrato in amplitude. In this paper, the envelopes of consonant intervals and chords are modelled mathematically by approximate formulas. They contain one variable for the intervals and two variables for the chords. The formulas include deviations of one full trigonometric period, thus being valid for any tuning system. In the case of intervals, the corresponding ripples are obtained by following a line (1D) at a specific velocity and, in the case of chords, by following a line on a graph (2D) at specific velocity and direction. The corresponding audio files considering pure tones are also obtained.

Increasing the complexity of isolated musical chords benefits concurrent associative memory formation

The effects of background music on learning and memory are inconsistent, partially due to the intrinsic complexity and diversity of music, as well as variability in music perception and preference. By stripping down musical harmony to its building blocks, namely discrete chords, we explored their effects on memory formation of unfamiliar word-image associations. Chords, defined as two or more simultaneously played notes, differ in the number of tones and inter-tone intervals, yielding varying degrees of harmonic complexity, which translate into a continuum of consonance to dissonance percepts. In the current study, participants heard four different types of musical chords (major, minor, medium complex, and high complex chords) while they learned new word-image pairs of a foreign language. One day later, their memory for the word-image pairs was tested, along with a chord rating session, in which they were required to assess the musical chords in terms of perceived valence, tension, and the extent to which the chords grabbed their attention. We found that musical chords containing dissonant elements were associated with higher memory performance for the word-image pairs compared with consonant chords. Moreover, tension positively mediated the relationship between roughness (a key feature of complexity) and memory, while valence negatively mediated this relationship. The reported findings are discussed in light of the effects that basic musical features have on tension and attention, in turn affecting cognitive processes of associative learning.

From Ramos to Rameau

Abstract This article explores the advent of two foundational characteristics of the modern concept of harmony inaugurated by Rameau's Traité de l'harmonie (1722): first, that its principal objects are sonorities of three or more distinct pitch classes, that is, consonant and dissonant chords; and second, that these chords “move” from one to the next in ways determined by certain inherent relations among them, in a process in which dissonances, as well as consonances, play a significant if not crucial role. This article shows that the ancestors of these two fundamental properties of harmony, newly understood as a specifically polyphonic phenomenon, first emerged into theoretical discourse in polemical writings of the Northern Italian theorists Nicolò Burzio (1487), Giovanni Spataro (1491), and Franchino Gaffurio (1496, 1518), sparked by the inflammatory views of Bartolomeo Ramos de Pareia (1482). Moreover, while these ideas about harmony come to cohabit in Gioseffo Zarlino's Istitutioni harmoniche (1558), they were initially proposed not as complementary but as explicitly competing new conceptions of the nature of harmony, advanced to support their authors' polemical positions and attacks on each other.

The Influence of Music on the Behaviour of Persons with Autism Spectrum Disorder (ASD) and Low Cognitive Functioning: A Systematic Observational Study

ABSTRACT : Persons with Autism Spectrum Disorder (ASD) and low cognitive functioning tend to demonstrate regulatory responses to auditory sensations, leading to disturbed behaviours such as self-stimulation, stereotypical movements, even aggression and self-harm. The aim of this study was to investigate whether listening to specific sounds and music reduced these behaviours. A systematic observational study of 16 participants was carried out with parental consent. A range of music types and sounds were played to participants including dissonant music (contemporary classical with dissonant chords), consonant music (classical romantic with consonant chords) and ambient sounds. Intermittent periods of silence between tracks were introduced to check for any potential influence of previous listening. It was noted that disturbed behaviour was least evident during periods of ‘silence’ (without additional auditory input), compared to any of the other conditions. Silence was therefore used as a baseline before listening to any sounds. Consonant music appeared to decrease disturbed behaviours compared with the other types of music and proved more effective than silence. These findings suggest that using specific types of music might help decrease some disturbed behaviour.

Spontaneous Mouse Behavior in Presence of Dissonance and Acoustic Roughness.

According to a novel hypothesis (Arnal et al., 2015, Current Biology 25:2051–2056), auditory roughness, or temporal envelope modulations between 30 and 150 Hz, are present in both natural and artificial human alarm signals, which boosts the detection of these alarms in various tasks. These results also shed new light on the unpleasantness of dissonant sounds to humans, which builds upon the high level of roughness present in such sounds. However, it is not clear whether this hypothesis also applies to other species, such as rodents. In particular, whether consonant/dissonant chords, and particularly whether auditory roughness, can trigger unpleasant sensations in mice remains unknown. Using an autonomous behavioral system, which allows the monitoring of mouse behavior over a period of weeks, we observed that C57Bl6J mice did not show any preference for consonant chords. In addition, we found that mice showed a preference for rough sounds over sounds having amplitude modulations in their temporal envelope outside the “rough” range. These results suggest that some emotional features carried by the acoustic temporal envelope are likely to be species-specific.

Is consonance attractive to budgerigars? No evidence from a place preference study

Consonant tone combinations occur naturally in the overtone series of harmonic sounds. These include sounds that many non-human animals produce to communicate. As such, non-human animals may be attracted to consonant intervals, interpreting them, e.g., as a feature of important social stimuli. There is preliminary evidence of attraction to consonance in various bird species in the wild, but few experimental studies with birds. We tested budgerigars (Melopsittacus undulatus) for attraction to consonant over dissonant intervals in two experiments. In Experiment 1, we tested humans and budgerigars using a place preference paradigm in which individuals could explore an environment with multiple sound sources. Both species were tested with consonant and dissonant versions of a previously studied piano melody, and we recorded time spent with each stimulus as a measure of attraction. Human females spent more time with consonant than dissonant stimuli in this experiment, but human males spent equal time with both consonant and dissonant stimuli. Neither male nor female budgerigars spent more time with either stimulus type. In Experiment 2, we tested budgerigars with more ecologically relevant stimuli comprised of sampled budgerigar vocalizations arranged into consonant or dissonant chords. These stimuli, however, also failed to produce any evidence of preference in budgerigar responses. We discuss these results in the context of ongoing research on the study of consonance as a potential general feature of auditory perception in animals with harmonic vocalizations, with respect to similarities and differences between human and budgerigar vocal behaviour, and future methodological directions.

Evaluating Concept Formation in Multiple Exemplar Training with Musical Chords

The present study evaluated a teaching procedure based on Multiple Exemplar Training (MET) to establish conditional relations between musical chords and printed words. In addition, generalization tests were provided to participants to assess concept formation processes for different types of musical chords (e.g., major, minor, consonant, and dissonant). Forty college students were equally distributed into two groups. Group 1 was taught the conditional relations between major and minor chords using different notes and the printed words “MAJOR” and “MINOR.” Group 2 was taught the conditional relations between consonant and dissonant chords using different notes and the printed words “CONSONANT” and “DISSONANT.” Generalization tests were given in between each training phase. Five participants from Group 1 and seven participants from Group 2 achieved the learning criteria for all training phases. The results revealed that the average percentage of correct responses during the last generalization test was higher when compared to the pretest for both groups. Our findings suggest that the MET procedure was suitable for establishing conditional relations between musical chords and printed words. Moreover, the generalization test results revealed the concept formation processes for some participants.

Unilateral hf-tRNS over the temporal cortex does not influence pleasantness of musical chords

The “consonance effect” is the pleasant and unpleasant evaluation attributed to consonant and dissonant music, respectively. Different studies in this domain revealed a left-hemispheric superiority for dissonance and a right-hemispheric superiority for consonance. We investigated the causal relationship between the consonance effect and the activity of the cerebral hemispheres by applying high frequency transcranial Random Noise Stimulation (hf-tRNS) over the left or right auditory cortex in a group of 24 healthy volunteers. Results confirm the consonance effect, dissonant chords being judged as more unpleasant than consonant chords, and show that hf-tRNS does not influence the pleasantness evaluations of chords. We speculate that the auditory cortex is directly involved in consonance and dissonance processing, but that pleasantness evaluations could take place in the anterior areas of the brain. This is the first evidence concerning the effects of the modulatory activity in each cerebral hemisphere and the consonance effect.

Brain processing of consonance/dissonance in musicians and controls: a hemispheric asymmetry revisited.

It was investigated to what extent musical expertise influences the auditory processing of harmonicity by recording event-related potentials. Thirty-four participants (18 musicians and 16 controls) were asked to listen to hundreds of chords, differing in their degree of consonance, their complexity (from two to six composing sounds) and their range (distance of two adjacent pitches, from quartertones to more than 18 semitone steps). The task consisted of detecting rare targets. An early auditory N1 was observed that was modulated by chord dissonance in both groups. The response was generated in the right medial temporal gyrus (MTG) for consonant chords but in the left MTG for dissonant chords according to swLORETA reconstruction performed. An anterior negativity (N2) was enhanced only in musicians in response to chords featuring quartertones, thus suggesting a greater pitch sensitivity for simultaneous pure tones in the skilled brain. The P300 was affected by the frequency range only in musicians, who also showed a greater sensitivity to sound complexity. A strong left hemispheric specialization for processing quartertones in the left temporal cortex of musicians was observed at N2 level (250-350ms), which was observed on the right side in controls. Additionally, in controls, widespread activity of the right limbic area was associated with listening to close frequencies causing disturbing beats, possibly suggesting a negative aesthetic appreciation for these stimuli. Overall, the data show a finer and more tuned neural representation of pitch intervals in musicians, linked to a marked specialization of their left temporal cortex (BA21/38).

Dis-sonare - Auseinanderklingen in der Musik/ Dis-sonare – Sounding apart in music

Abstract The concept of dissonance is applied in all European languages to different notes sounding together. The varying evaluation of physical, perception psychology and aesthetic aspects from mediaeval times to the present has resulted in a wide variety of reasons given for the border between consonant and dissonant chords and the role of dissonance in the history of music. Since the 20th century the view of New Music that Schonberg’s emancipation of dissonance marked the end of tonality has contrasted with the uninhibited and expressive use of dissonance in largely tonal pop and film music.

Losing the music: aging affects the perception and subcortical neural representation of musical harmony.

When two musical notes with simple frequency ratios are played simultaneously, the resulting musical chord is pleasing and evokes a sense of resolution or "consonance". Complex frequency ratios, on the other hand, evoke feelings of tension or "dissonance". Consonance and dissonance form the basis of harmony, a central component of Western music. In earlier work, we provided evidence that consonance perception is based on neural temporal coding in the brainstem (Bones et al., 2014). Here, we show that for listeners with clinically normal hearing, aging is associated with a decline in both the perceptual distinction and the distinctiveness of the neural representations of different categories of two-note chords. Compared with younger listeners, older listeners rated consonant chords as less pleasant and dissonant chords as more pleasant. Older listeners also had less distinct neural representations of consonant and dissonant chords as measured using a Neural Consonance Index derived from the electrophysiological "frequency-following response." The results withstood a control for the effect of age on general affect, suggesting that different mechanisms are responsible for the perceived pleasantness of musical chords and affective voices and that, for listeners with clinically normal hearing, age-related differences in consonance perception are likely to be related to differences in neural temporal coding.

Characteristics of Evoked Changes in EEG Spectral Power and Evoked Potentials on Perception of Musical Harmonies in Musicians and Nonmusicians

We report here our studies on activity evoked in the brain on perception of consonant and dissonant chords in subjects with different levels of musical education and experience of playing music. Perception of chords was associated with significantly greater theta-rhythm power levels in the frontomedial leads, which were more marked for consonant chords than dissonant chords. Perception of consonant chords in nonmusicians was accompanied by greater activation of the left frontal lobe than the right, while this asymmetry was not seen in musicians. In addition, the amplitudes of the early components (N100, P200) of evoked potentials for both types of chord were significantly greater in musicians. These results may be evidence for more effective perception strategies for musical harmony and less emotional perception of chords in musicians.

The “consonance effect” and the hemispheres: A study on a split-brain patient

The association between musical consonance and pleasantness, and between musical dissonance and unpleasantness (“consonance effect”) is well established. Furthermore, a number of studies suggest the main involvement of the left hemisphere in the perception of dissonance and that of the right hemisphere in the perception of consonance. In the present study, the consonance effect was studied in a callosotomized patient, D. D. C. and in a control group. In binaural presentations, the patient did not attribute different pleasantness judgements to consonant and dissonant chords, differently from the control group who showed the consonance effect. However, in dichotic presentations (e.g. a chord in one ear and white noise in the other ear), a trend towards the consonance effect was found in D. D. C., but only when chords were presented in his right ear (left hemisphere), whereas the control group confirmed the known hemispheric asymmetry in labelling the pleasantness of consonant and dissonant chords. These results suggest that the right-hemispheric superiority in appreciating consonance might hide the inability of the right hemisphere to classify dissonant chords as unpleasant in the split-brain, whereas the left hemisphere seems capable to differently label the pleasantness of consonant and dissonant chords, even if it is more sensitive to dissonance.

Phase locked neural activity in the human brainstem predicts preference for musical consonance

When musical notes are combined to make a chord, the closeness of fit of the combined spectrum to a single harmonic series (the ‘harmonicity’ of the chord) predicts the perceived consonance (how pleasant and stable the chord sounds; McDermott, Lehr, & Oxenham, 2010). The distinction between consonance and dissonance is central to Western musical form. Harmonicity is represented in the temporal firing patterns of populations of brainstem neurons. The current study investigates the role of brainstem temporal coding of harmonicity in the perception of consonance. Individual preference for consonant over dissonant chords was measured using a rating scale for pairs of simultaneous notes. In order to investigate the effects of cochlear interactions, notes were presented in two ways: both notes to both ears or each note to different ears. The electrophysiological frequency following response (FFR), reflecting sustained neural activity in the brainstem synchronised to the stimulus, was also measured. When both notes were presented to both ears the perceptual distinction between consonant and dissonant chords was stronger than when the notes were presented to different ears. In the condition in which both notes were presented to the both ears additional low-frequency components, corresponding to difference tones resulting from nonlinear cochlear processing, were observable in the FFR effectively enhancing the neural harmonicity of consonant chords but not dissonant chords. Suppressing the cochlear envelope component of the FFR also suppressed the additional frequency components. This suggests that, in the case of consonant chords, difference tones generated by interactions between notes in the cochlea enhance the perception of consonance. Furthermore, individuals with a greater distinction between consonant and dissonant chords in the FFR to individual harmonics had a stronger preference for consonant over dissonant chords. Overall, the results provide compelling evidence for the role of neural temporal coding in the perception of consonance, and suggest that the representation of harmonicity in phase locked neural firing drives the perception of consonance.

Evoked Changes in EEG Band Power on Perception of Consonant and Dissonant Chords

Few studies have been reported on the effects of music on brain biopotentials. The present investigation addresses the perception of consonant and dissonant chords by humans. Subjectively presented consonant intervals were evaluated as more harmonic and pleasant than dissonant intervals. Analysis of evoked brain activity showed that the perception of dissonant chords was accompanied by activation of the right frontal lobe, which regulates negative emotions, while consonant chords activated the left frontal area, which regulates positive emotions.

Event-related brain activity changes to consonant and dissonant chords in musicans and non-musicans

The present study assessed brain activity changes related to perception of consonant and dissonant chords by musicians and non-musicians. Perception of dissonant chords in non-musicians was accompanied by increase of lower theta activity over right anterior regions, while consonant chords induced greater theta activity over left anterior regions; this pattern of asymmetrical activation was not observed in musicians. ERP analysis revealed that musicians had greater amplitude of early components (P100, N200) than non-musicians irrespective of chord type. The obtained results reflect more efficient musical harmony processing and, possibly, less emotional perception of chords in musicians.

Music processing similarities between sleeping newborns and alert adults: cause for celebration or concern?

[This corrects the article on p. 492 in vol. 4, PMID: 23966962.].

The basis of musical consonance as revealed by congenital amusia.

Some combinations of musical notes sound pleasing and are termed "consonant," but others sound unpleasant and are termed "dissonant." The distinction between consonance and dissonance plays a central role in Western music, and its origins have posed one of the oldest and most debated problems in perception. In modern times, dissonance has been widely believed to be the product of "beating": interference between frequency components in the cochlea that has been believed to be more pronounced in dissonant than consonant sounds. However, harmonic frequency relations, a higher-order sound attribute closely related to pitch perception, has also been proposed to account for consonance. To tease apart theories of musical consonance, we tested sound preferences in individuals with congenital amusia, a neurogenetic disorder characterized by abnormal pitch perception. We assessed amusics' preferences for musical chords as well as for the isolated acoustic properties of beating and harmonicity. In contrast to control subjects, amusic listeners showed no preference for consonance, rating the pleasantness of consonant chords no higher than that of dissonant chords. Amusics also failed to exhibit the normally observed preference for harmonic over inharmonic tones, nor could they discriminate such tones from each other. Despite these abnormalities, amusics exhibited normal preferences and discrimination for stimuli with and without beating. This dissociation indicates that, contrary to classic theories, beating is unlikely to underlie consonance. Our results instead suggest the need to integrate harmonicity as a foundation of music preferences, and illustrate how amusia may be used to investigate normal auditory function.

On Musical Dissonance

psychoacoustic theories of dissonance often follow Helmholtz and attribute it to partials (fundamental frequencies or overtones) near enough in frequency to affect the same region of the basilar membrane and therefore to cause roughness, i.e., rapid beating. In contrast, tonal theories attribute dissonance to violations of harmonic principles embodied in Western music. We propose a dual-process theory that embeds roughness within tonal principles. The theory predicts the robust increasing trend in the dissonance of triads: major < minor < diminished < augmented. Previous experiments used too few chords for a comprehensive test of the theory, and so Experiment 1 examined the rated dissonance of all 55 possible three-note chords, and Experiment 2 examined a representative sample of 48 of the possible four-note chords. The participants' ratings concurred reliably and corroborated the dual-process theory. Experiment 3 showed that, as the theory predicts, consonant chords are rated as less dissonant when they occur in a tonal sequence (the cycle of fifths) than in a random sequence, whereas this manipulation has no reliable effect on dissonant chords outside common musical practice.

The variation of hemodynamics relative to listening to consonance or dissonance during chord progression

Objective: The aim of the present study was to identify the variation of cerebral hemodynamics in relation to listening to chord progressions involving consonant or dissonant chords based on western music theory by near-infrared spectroscopy. We also tried to find out the influence of musical education on the cortical hemodynamics.Methods: Twenty subjects participated in this study. They were classified into two groups, namely persons with and without special musical training histories. We used two types of chord progressions involving consonant and dissonant chords as stimuli. Then, the hemodynamics of each group was analyzed by optical topography to investigate the effects of each type of chord in the areas of left and right auditory cortices.Results: In the left auditory cortex (superior temporal cortex), the group with higher musical training showed a significant increase in oxyhemoglobin (oxy-Hb) when listening to dissonant chords as compared with consonant chords, while the group without higher education for music did not show significant changes in oxy-Hb between consonant chords and dissonant chords. No significant changes in oxy-Hb in the right auditory cortex were observed in response to either chord, neither in the group with higher education for music, nor in the group without it.Discussion: Our results suggest that special musical training could enhance music-syntactic processing in the left auditory area and react more sensitively to the dissonant chords.