Why are minor keys often associated with negative emotions?

In modern Western music theory, the tendency to associate minor keys with negative emotions—such as melancholy or pathos—is widely recognized, though the precise reasons for this association remain unclear.12

Several theories have been proposed to explain this phenomenon:

• Cultural Conditioning: It is suggested that long-standing cultural associations have solidified the distinction between major and minor tonalities in the listener's mind.1
• Frequency of Use: Major keys are more common in the Western repertoire, which may influence how listeners perceive the relative "uncommonness" or emotional weight of minor keys.1
• Acoustic Properties: Some theorists point to the possibility that minor keys are perceived as more dissonant or are more likely to result in unstable tonality compared to their major counterparts.1
• Interval Structure: Historically, the Doctrine of the affections suggested that specific musical devices could elicit involuntary emotional responses, with some theorists arguing that "sadness" is naturally evoked by smaller intervals, such as the minor third that characterizes the minor scale.34

Ultimately, while these theories offer potential explanations, the emotional impact of music is deeply tied to its specific context, and no single factor definitively dictates how a listener will interpret a key.53