Heavy metal music is more emotionally complicated than people often think. For her 2026 thesis titled “Affective Responses To Major and Minor Chords In Heavy Metal Music”, presented to the faculty of The University of Houston-Clear Lake for the Degree Master of Science in Psychology, Faith Carlos conducted research examining how chords affect listeners’ feelings in metal. In her thesis she explains that in Western music, major chords are typically heard as happy and bright, while minor chords sound sad or tense. But metal isn’t typical Western music. It relies on loud sounds, fast rhythms, harsh textures, and emotions like power, struggle, and resilience. So Carlos asked whether those familiar ideas about major and minor chords still hold in metal, or whether the genre changes how people experience harmony entirely.
Many studies in other genres show quick, automatic emotional responses to chords — brain research demonstrates that people react differently to major and minor chords within milliseconds. But those studies mostly examined classical, pop, or jazz, not metal. In metal, emotional responses may be shaped by the intense style, fan community, and personal meaning beyond just tones. People who love metal often describe the genre helping them feel strong, cathartic, or connected. This raises complex questions: Do major and minor chords still map to happy and sad in metal? Does familiarity with the genre, musical context, or metal’s cultural identity change how listeners respond?
Two Experiments, One Big Question
To explore this, Carlos designed two experiments using short metal clips built around either major or minor chords. Participants rated each clip using the Self-Assessment Manikin (SAM), a picture-based scale measuring valence (how pleasant or unpleasant the music felt) and arousal (how energized or calm it made them feel). Music preferences were measured using the STOMP test, which captures broad tastes — including whether someone gravitates toward intense, rebellious music — allowing researchers to see whether loving metal changed how people responded to chord types.
Experiment 1 was conducted online. Participants listened to roughly 60 short instrumental clips, evenly split between major and minor, using headphones in quiet environments. Keeping clips instrumental ensured that lyrics couldn’t influence ratings.
The results were surprising. Minor chords were rated slightly more pleasant than major ones, but the difference was small and statistically unreliable. Arousal ratings were nearly identical for both chord types. A generalized linear model (GLM) revealed that people who liked metal more tended to rate the music as more pleasant and arousing overall — but chord type itself produced no clear effect on either dimension.
Adding Brain Data
Experiment 2 went further by adding EEG brain activity monitoring alongside the same SAM ratings. Researchers focused on beta waves, which are linked to arousal and cognitive engagement, comparing baseline activity against responses to major and minor chords.
The behavioral results mirrored Experiment 1 — no significant difference in valence or arousal ratings between chord types. More strikingly, the brain data told the same story. Beta activity showed no meaningful difference across baseline, major, and minor conditions. Even after accounting for individual metal preference, there was no reliable interaction between chord type and neural arousal. The brain simply wasn’t distinguishing between major and minor chords in a detectable way.
Why Metal Plays by Different Rules
Why might major and minor chords carry less emotional weight in metal? The genre is built on intense energy, distortion, and a strong sense of identity. Fans use metal for catharsis, empowerment, and community belonging. In that context, a chord’s emotional meaning gets shaped by far more than its type. Tempo, loudness, distortion texture, harmonic progression, and the song’s overall message all contribute — potentially overwhelming the straightforward major-equals-happy, minor-equals-sad formula found in other genres. Listeners’ deep familiarity and personal connection with metal likely soften what would otherwise be a predictable emotional response.
The Takeaway
Across both self-reported feelings and brain activity, major and minor chords did not produce the clear emotional differences Carlos’ team expected. General music preference influenced how pleasant or energizing the music felt, but chord type alone wasn’t driving those responses.
This doesn’t close the door on the question. Future research could explore other neural measures, longer musical excerpts, different listening contexts, or more advanced brain analysis methods to detect subtler effects. But for now, the findings send a clear message: the simple major/minor rule from traditional music theory doesn’t apply the same way to heavy metal. In a genre defined by intensity, culture, and personal meaning, emotional responses to harmony are far more nuanced — and far less predictable — than a single chord type can explain.
Download and read Faith Carlos’ entire thesis, “Affective Responses To Major and Minor Chords In Heavy Metal Music” here.
