Harmony is natural in most instruments, and is actually universal mathematical phenomenon
I play the violin in an orchestra and you notice a few things about the strong link between mathematics and music.
If you play an 'open' string on a string instrument (ie, a tensioned string between two points, no fingering, on a violin or cello), you get a set frequency. Divide the string in half, and the frequency lifts up an octave. Divide that half into half, it goes up another octave, and so on.
Get an adjustable tube with a reed or mouthpiece (a common modern instrument is a trombone). Extend the tube by twice the length, and the sound drops an octave.
Get a glass and fill with water and a spoon. Hit it with the spoon and you get a note. Pour out half the water and hit it again, you get an octave higher. This is the same principle as a xylophone.
Same for harps, tubular bells, marimbas and many other instruments. It is universal and cross cultural. Octaves are the primal harmony, cultural factors affect how that octave is divided further, and different cultures divide in different ways (Korean music divides in 5, European in 8, and others differently) but essentially it all starts with that initial harmony.
The individual notes established, the only remaining factor in playing in a group is to match their base notes. This is called tuning.
In an orchestral setting, all instruments tune to a common instrument (usually the oboe) to 'set' their base note to a common frequency. If you do not do this, you immediately sense 'disharmony' or 'out of tune'. This is not just an emotion, it is a mathematical mismatch, which you can hear a 'wobble' as the two frequencies fight each other. Tuning a violin you must do so using only your ear, you find the right note when it no longer 'wobbles', and the frequency matches with the oboe and others.
What's more is you can easily know who is 'out of tune', their notes stick out like a sore thumb, and you don't need to be musically educated to sense this. Your group of flute players around your mammoth roast must adjust the length of their instrument to match each other prior to playing, otherwise it would be a mad jumble of incoherent frequencies, as can happen in modern orchestras today.
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This seems relevant: https://www.sciencedaily.com/releases/2013/02/130214103816.htm
– Tim B – 2018-11-29T13:46:43.6671No doubt a useful link, but it does seem to suppose that just because something can be changed, it isn't natural...which is entirely illogical. – Giu Piete – 2018-11-29T15:03:38.440
3Can we narrow the question? Humans like sound, a consequence of having ears. We grow up with birdsong, the sussuration of wind, and the crash of water. I don't know if rythym is natural to us, but the combination of sound obviously is. Thus, it's human nature to jam. But what is harmony but a modern definition? Who is to say that harmony to one is cacaphony to another? You're using modern definitions to ask about an evolutionary trait - and I don't believe that's as associative as it may seem. – JBH – 2018-11-29T17:07:45.337
@JBH I define homophony and polyphony. All multi-part music falls into one or the other category, but not both. Then I ask you to decide between them. What else do you want? – kingledion – 2018-11-29T17:21:36.237
2There’s a deeper question: if they did play in harmony, would it sound harmonious to us? Does harmony depend upon specific math relations between waveforms or does harmony depend upon hitting intervals that match audience expectations? – SRM – 2018-11-29T18:11:46.643
Well, coyotes do it :-) – jamesqf – 2018-11-29T18:17:40.887
My point is a wordy way of saying what @SRM said. Beauty is subjective. The definitions are modern and may not stand up to a 1600s interpretation, much less the basis for justifying an evolutionary concept. Honestly, though I doubt anyone can answer the question (what do any of us know about the singing abilities of neanderthalls?), the only practical answer is "yes" because all it takes is two people to sing together and one person to like what they hear and harmony is born - whether it meets modern definitions or not. – JBH – 2018-11-29T19:06:02.663
How could this question possibly be on-topic here? This is asking about real-world history and has nothing to do with worldbuilding. – Clint – 2018-11-29T21:08:57.057
@Clint because there's no real world answer to the question -- this question asks us to speculate based on analogous situations. There's no way any other stack exchange would touch such a hypothetical except to say, "There is no evidence to support any answer." Or similar reason for closing. – SRM – 2018-11-30T01:43:19.773
Simplest multi-piece music, stomp and clap :) Simplest harmony in your case is flute + voice. These could be in tune or for contrast:
and saw... **drom-roll** fire!The "primitive" people spent generations practicing same instruments and were quite creative, according to Wikie, both homophony and polyphony predate Western music. – Dima Tisnek – 2018-11-30T03:00:31.313@kingledion: Actually, there is (1) monophony (only one melody, possibly sung by multiple parallel voices; typical for the Middle Ages), (2) polyphony (two or more voices singing independent melodies, sometimes in harmony and sometimes in tension, each melody being in itself melodious; typical for the Renaissance and partially baroque), and (3) homophony (multiple voices singing different parts, one voice being dominant and the others harmonizing consonantly or dissonantly; typical for classical and post-classical music).
– AlexP – 2018-11-30T12:56:38.497