Musical harmony is processed during sleep: a proof-of-concept study

Moderating effects of chord progressions on the emotional experience of major and minor chords.

Musical chords are arguably the smallest building blocks of music that retain emotional information. Major chords are generally perceived as positive- and minor chords as negative-sounding, but there has been debate concerning how early these emotional connotations may be processed. To investigate this, emotional facial stimuli and musical chord stimuli were simultaneously presented to participants, and facilitation of processing was measured via event-related potential (ERP) amplitudes. Decreased amplitudes of the P1 and N2 ERP components have been found to index the facilitation of early processing. If simultaneously presented musical chords and facial stimuli are perceived at early stages as belonging to the same emotional category, then early processing should be facilitated for these congruent pairs, and ERP amplitudes should therefore be decreased as compared to the incongruent pairs. ERPs were recorded from 30 musically naive participants as they viewed happy, sad, and neutral faces presented simultaneously with a major or minor chord. When faces and chords were presented that contained congruent emotional information (happy-major or sad-minor), processing was facilitated, as indexed by decreased N2 ERP amplitudes. This suggests that musical chords do possess emotional connotations that can be processed as early as 200 ms in naive listeners. The early stages of processing that are involved suggest that major and minor chords have deeply connected emotional meanings, rather than superficially attributed ones, indicating that minor triads possess negative emotional connotations and major triads possess positive emotional connotations.

Musicians and nonmusicians listened to major, minor, and dissonant musical chords while their BOLD brain responses were registered with functional magnetic resonance imaging. In both groups of listeners, minor and dissonant chords, compared with major chords, elicited enhanced responses in several brain areas, including the amygdala, retrosplenial cortex, brain stem, and cerebellum, during passive listening but not during memorization of the chords. The results indicate that (1) neural processing in emotion-related brain areas is activated even by single chords, (2) emotion processing is enhanced in the absence of cognitive requirements, and (3) musicians and nonmusicians do not differ in their neural responses to single musical chords during passive listening.

The paper offers a solution to the centuries-old puzzle — why the major chords are perceived as happy and the minor chords as sad. A theory and a formula of musical emotions were created. They define the sign and the amplitude of the utilitarian emotional coloration of separate major and minor chords through relative pitches of constituent sounds. The standard form of notation of the relative frequencies by rational quantities is accompanied by replacement of them with the sonant formulas. It gives a possibility of extraction of data about relative pitches from results of detail study of a notation of the musical scores by means of sonantometry.

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.

A cochlear implant (CI) restores hearing for profoundly deaf patients by transmitting sound to an array of electrodes that stimulates the inner ear. The small number of frequency bands and limited transmission of temporal fine structure affects the music perception. The present work investigates the pleasantness of chords and chord sequences in adults using such electric hearing. In the first task, participants compared chord types according to their perceived pleasantness. Normal-hearing listeners judged the major chord and the minor chord as the most pleasant ones compared to other chord types. CI users appraised the major chord as more consonant than other chord types. The second task used four-chord sequences, half of which ended on an authentic V-I cadence. In the other presentations, the final tonic was replaced either by a transposed major chord or by a dissonant chord. The participants had to judge whether the ending was conclusive. While normal-hearing listeners preferred authentic cadences, all but one CI user assessed the modified cadences as similarly satisfying. The results indicate that CI users appreciated consonance of isolated chords to a certain extent similar to normal-hearing listeners. Nevertheless, the majority of CI users fail to register the musical syntax in the harmonic progression of cadences.

Brain activities to major and minor chords and to major and minor cadence sequences were measured by sparse scanning fMRI. Areas activated by major and minor chords and cadence sequences were examined. Some of them are known to be related to emotion, motivation, arousal or reward. In general, minor chords activated larger areas of brain regions than major chords. Some activated areas have not been especially associated with emotion or music processing. Cadence results are somewhat ambiguous probably due to the control sequence used. Also individual differences were considerable in both experiments.

ly summarized by the circle of fifths. Analogously, a net exposed to Indian ragas fills in expected tones when presented with subsets of the raga tones. An auto-associative net trained on the scales of one culture can be tested with the scales of another, making predictions about tonal implications 46 Computer Music Journal This content downloaded from 157.55.39.231 on Thu, 06 Oct 2016 04:43:25 UTC All use subject to http://about.jstor.org/terms generated in the minds of listeners hearing an unfamiliar form of music. A net trained on the Western major and minor scales seems to assimilate some Indian ragas to the Western scales, sometimes shifting the tonic (Bharucha and Olney 1989). Learning Hierarchical Representations Through Self-Organization Hierarchical relationships, such as between tones, chords, and keys, can be learned passively by algorithms for self-organization (Kohonen 1984; Linsker 1986; Rumelhart and McClelland 1986; Carpenter and Grossberg 1987). Most self-organization mechanisms assume the prior existence of abstract units into which the input units feed. These abstract units initially have no specialization, since the links from the input units are initially random. However, repeated exposure to commonly occurring patterns causes some of these abstract units to tune their responses to these patterns. One of the more straightforward, self-organization algorithms, called competitive learning (Rumelhart and McClelland 1986) accomplishes this as follows. For any given pattern some arbitrary abstract unit will respond more strongly than any other, simply because the weights are initially random. Of the links that feed into this unit, those that contributed to its activation are strengthened and the others are weakened. This unit's response will subsequently be even stronger in the presence of this pattern and weaker in the presence of other, dissimilar patterns. In similar fashion, other abstract units learn to specialize to other patterns. This process can be continued to even more abstract layers, at which units become tuned to patterns that commonly occur in the lower layer. The overwhelming preponderance of major and minor chords in the popular Western musical environment would drive such a net to form units that respond accordingly. Furthermore, the typical combinations in which these chords are used would drive units at a more abstract layer to register larger organizational units such as keys. The notion that individual neurons specialize to respond to complex auditory patterns has some preliminary empirical support from single-cell recording studies on animals (Weinberger and McKenna 1988). Once these chord and key units have organized themselves, the net models the implication of tones, chords, and keys given a set of tones. A hierarchical constraint satisfaction net built on this organization has been reported in earlier work (Bharucha 1987a; 1987b). In this net, called MUSACT, activation spreads from tone units to chord and key units and reverberates phasically through the net until a state of equilibrium is achieved. At equilibrium, all constraints inherent in the net have been satisfied. Given a key-instantiating context, the unit representing the tonic becomes the most highly activated. The other chord units are activated to lesser degrees the further they are from the tonic along the circle of fifths. Two behaviors of the net illustrate its emergent properties. First, the above activation pattern does not require the tonic chord to be played at all. An F major chord followed by a G major chord will cause the C major chord unit to be the most highly activated. Second, the circle of fifths implicit in the activation pattern cannot be accounted for on the basis of shared tones alone. If a C major context chord is played, the D major chord unit is more highly activated than the A major chord unit, even though the latter shares one tone with the sounded chord (C major) and the former shares none at all. A careful tracking of the net's behavior as activation reverberates and before it converges to an equilibrium state reveals a lower initial activiation of D major over A major, reflecting an initial bottom-up influence of shared tones. As activation has a chance to reverberate back from the key units (a top-down influence), this advantage is lost, and D major overtakes A major. So the circle of fifths is truly an emergent property of the simultaneous satisfaction of elementary associations between tones and clusters of tones. See Bharucha (1987a; 1987b) for details. Learning With Sequential Nets Some of the schematic expectancies that are essentially sequential, as in chord progressions, can be modeled with sequential nets. The architecture

he standard western music notation for major and minor chords is available worldwide. However, understanding major and minor chords can be very difficult for learners, particularly children. It's challenging to memorize all major and minor chords and their roots. This invention aims to make it easier for children to understand and remember chords, which can be easily applied to standard piano and other instruments. The new method utilizes numerical techniques to convey chords. Octave notes are categorized into two different groups: major and minor chords, using numerical methods. Two main equations are implemented, making it very easy to understand all major and minor chords.

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

Music practice since childhood affects the development of hearing skills. An important classification in Western music is the chords' major-minor dichotomy. Its preattentive auditory discrimination was studied here using a mismatch negativity (MMN) paradigm in 13-year-olds with active hobbies, music-related (music group) or other (control group). In a context of root major chords, root minor chords and inverted major chords were presented infrequently. The interval structure of inverted majors differs more from root majors than the interval structure of root minors. However, the identity of the chords is the same in inverted and root majors (major), but different in root minors. The deviant chords introduced no new frequencies to the paradigm. Hence, an MMN caused by physical deviance was prevented. An MMN was elicited by the minor chords but not by the inverted majors. The MMN amplitude in the music group was larger than in the control group. Thus, the conceptual discrimination skills are present already in the preattentive processing level of the auditory cortex, and musical training can advance these skills.

The preattentive processing of major vs. minor chords in the human brain: An event-related potential study

Musical chords play an essential role, especially in Western music, and the corresponding consonance–dissonance contrasts and emotional continua are still the targets of investigation in psychoacoustics and neurophysiology. In the present study, we define the simplicity of frequency ratios and simplicity of period ratios for the constituents of a chord and propose that those measures should be used as the two coordinate axes in the plane for plotting chords. In this plane, the major and minor chords are reflections of each other with respect to the diagonal . The other chord pair in the same relationship is the major–minor seventh (dominant seventh) and the half-diminished seventh chords. The other triads and seventh chords do not make such pairs of different categories of chords. It was also found that at least for triads, the sum and the difference seem to correspond to subjective consonance and the melancholic/sad emotional ratings, respectively. Implications of these findings are discussed. The proposed simple presentation may help interpret and model psychoacoustic and neurophysiological results on musical chords.

Musical expertise is associated with structural and functional changes in the brain that underlie facilitated auditory perception. We investigated whether the phase locking (PL) and amplitude modulations (AM) of neuronal oscillations in response to musical chords are correlated with musical expertise and whether they reflect the prototypicality of chords in Western tonal music. To this aim, we recorded magnetoencephalography (MEG) while musicians and non-musicians were presented with common prototypical major and minor chords, and with uncommon, non-prototypical dissonant and mistuned chords, while watching a silenced movie. We then analyzed the PL and AM of ongoing oscillations in the theta (4–8 Hz) alpha (8–14 Hz), beta- (14–30 Hz) and gamma- (30–80 Hz) bands to these chords. We found that musical expertise was associated with strengthened PL of ongoing oscillations to chords over a wide frequency range during the first 300 ms from stimulus onset, as opposed to increased alpha-band AM to chords over temporal MEG channels. In musicians, the gamma-band PL was strongest to non-prototypical compared to other chords, while in non-musicians PL was strongest to minor chords. In both musicians and non-musicians the long-latency (> 200 ms) gamma-band PL was also sensitive to chord identity, and particularly to the amplitude modulations (beats) of the dissonant chord. These findings suggest that musical expertise modulates oscillation PL to musical chords and that the strength of these modulations is dependent on chord prototypicality.

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.