consonance and dissonance

Perceived qualities of musical chords and intervals. Consonance is often described as relative “stability,” and dissonance as “instability.” In musical contexts, certain intervals seem to call for motion by one of the tones to “resolve” perceived dissonance. The most consonant intervals are generally recognized as the unison and octave, and the next most consonant interval as the perfect fifth. Consonance tends to reflect the early intervals of the overtone series (which include, in addition to the octave and perfect fifth, the major and minor thirds and the perfect fourth), but many musical factors can affect the perception of consonance and dissonance.

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Mental conflict that occurs when beliefs or assumptions are contradicted by new information. The concept was introduced by the psychologist Leon Festinger (1919–89) in the late 1950s. He and later researchers showed that, when confronted with challenging new information, most people seek to preserve their current understanding of the world by rejecting, explaining away, or avoiding the new information or by convincing themselves that no conflict really exists. Cognitive dissonance is nonetheless considered an explanation for attitude change.

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• Consonance and dissonance in music are properties of an interval or chord
• Cognitive dissonance is a state of mental conflict.
• Dissonance in poetry is the deliberate avoidance of assonance, i.e. patterns of repeated vowel sounds. Dissonance in poetry is similar to cacophony and the opposite of euphony.