I recently listened to a neuroscience podcast that says we have been conditioned to associate them that way.

Another thing to think about is sad music in major and happy music in minor, it exists and it's not even terribly uncommon

I recall reading that on some cultures it is reversed.

Because you've been told it is that way. You've likely heard sad songs in major keys and happy songs in minor keys. Not to mention the fact that a lot of music pieces change keys multiple times (a lot of chord progressions in pop music are inspired by key progressions in more elaborate music).

The major third is slightly more consonant with the root note than the minor third. Consonance is sonically simpler.

It's mostly just conditioning. Major sounds happy and minor sounds sad to you, because that's the association you've heard again thousands of times over your whole lifetime listening to (I'm guessing) typical Western music.

But that association isn't universal at all! There are whole non-western musical traditions (eg Jewish, Balkan, Eastern European) where a ton of it is minor but not sad. Think of like Hava Nagila - that's 100% minor key and it's a party song sung at weddings that literally translates to "Let's Celebrate".

Heck, even in popular Western music there are plenty of examples of dark songs in a major key (Pumped up Kicks, Boy in the Bubble...) and happy songs in a minor key (Yeah - Usher; SexyBack - Timberlake; Just Dance - Lady Gaga...).

Basically, if you grew up listening to typical Western music, your brain assumes major = happy and minor = sad because based on your previous experience that's more likely true than the reverse. But there are many exceptions in Western music, and other non-Western types of music where it's not a good assumption to begin with.

Correct! For example the Jewish musical tradition is extensively minor, even the happiest of songs. Think of Hava Nagila. Musically, that's as minor as it gets - but it literally translates to "Let's Celebrate" and it's traditionally a party song sung by large groups at weddings.

Besides Jewish music, there is also a lot of other Balkan / Eastern European music that has this "reversed" rule and uses minor in ways that aren't meant to imply anything negative emotionally.

It's this! For people with a lifetime listening to Western (meaning North American and European) music, your brain is just assuming "major = happy and minor = sad" because that's what you've mostly been exposed to.

But eg in Jewish music, minor keys are used all the time and don't imply anything negative. Hava Nagila is super minor and it's a wedding song that literally translates to "Let's Celebrate".

And even in Western music, that "rule" of major = happy is far from universal. Pumped Up Kicks is a dark song in a major key, SexyBack by Timberlake and Yeah by Usher are happy songs in a minor key. There's tons of cases like this, they're just not the majority. Most sad songs are minor so it's just an association we develop from past experience.

That's an interesting question! I'm not sure why our brains make that correlation but I think it's fascinating that it seems to be universal. It's definitely worth exploring further to see if there's a biological basis for it.

That's a great question! It's certainly possible that the correlation is biologically innate, as it does appear to be universal. However, it could also be that we've developed an association between certain musical patterns and certain emotions over time. It could be a combination of both. It's really fascinating to think about!

Just to add to confusion, if you listen to major third above the root it sounds (if conditioned already) "happy" but it actually sound "sad" bellow root! Likewise with minor third, it sounds happy bellow root as oposed to "normal" sounding sad above the root.

I wouldnt say its only about sad or happy.

Major keys have an open sound, while minors have a conclusive sound that sounds, for the lack of better words, like an ending. Minor sounds more final and hammered down as a “conclusion”.

When i hear a minor key, i hear “final judgement”, the end, finality.

With majors i hear opportunity, opening, beginning, they sound like a beginning of something because it gives you an urge to keep adding more tones and notes on top of a major key, to keep going.

And many times we associate finality and the end with sadness, and opportunity and beginnings with “new good things to come” so to speak.

Similar to lets say spring and autumn. Spring is the beginning, the bloom, life sprouting, which to me, fits with major chords. And autumn is death, the end, depression, conclusion, which fits with minors.

As everyone else has said, I've heard it's mostly, if not only the result of social conditioning.

I'd love someone with some background to confirm or deny this, but I think in African drumming music (which I'm sure is incredibly varied), being much more rhythmic than classical Western music, it's the speed of a piece that determines the emotional impact. Fast pieces are happy, slow pieces are sad.