[GorgeRonde]

There is a whole field dedicated to this kind of study, namely sociolinguistics (see [1] for a short summary of the seminal experiment). Sociolinguistics study surface variations in language use that cannot be accounted by dialectology only (i.e. geographical factors) among speakers of the same language. There are clusters among linguistics uses, and it turns out they map to clusters in the space of social practices. For what I have studied of the field (not that much), it seems most of the time the variation is driven by the desire to belong or show you belong to the community of the users of the trait you adopt. It's said to be "inconscious" (pretty much like my masterful ability a handling language), but at the same time the subjects at hand can arrive at the same conclusions with the help of some introspection.

What's uncanny here is that having a goatee doesn't make you belong to any social group you could think of explicitly and enjoy belonging to. I guess the relationship is mostly driven by a mix of physionomical traits (gender + age) and the fact they correlate well to having a goatee (which isn't a tiny class anyway). Or there are indeed "deep" social structures to which we belong and are yet unable to identify.

[1] http://all-about-linguistics.group.shef.ac.uk/branches-of-li...

Edit: there may well be an immense data trove hidden in people's voice. That could be a very useful way to enrich datasets internally a bit like recommendation engines work: if my neighbour speaks like I do, then he must enjoy the same things as I.

[jcims]

Or it could be that a goatee physically influences the sound of the voice in a way that is perceptible to the algorithm. For example, damping transmission through the skin and attenuating reflections off the chin and upper pip.

[anigbrowl]

It doesn't. I worked as a sound engineer in film for a decade and I'm extremely forensically minded.

[jcims]

You motivated me to investigate.

Extreme example, compare audio at 4m and 21m - https://www.youtube.com/watch?v=6dbQ2OA4SRA

Clearly a different top end.

Did a little tinkering in Audacity and with the beard there's a standard roll off from 3khz to 10khz. Without there's a weird flat spot in the same area (both are averaged over 20 seconds or so)

[solarkraft]

But are you absolutely sure there aren't tiny, tiny differences? I don't think it's likely, but how can you be so sure?

[anigbrowl]

I'm dubious because of the frequency range of audio recordings (especially post compression on Youtube) and the size of cells, even large ones like hair follicles.

[ClassyJacket]

You can't know this.

[drusepth]

How do you know he can't know this?

[wanderfowl]

This feels very unlikely. Hairs are thin, non-absorptive, and spaced far enough apart to avoid much absorption. Unless it were an exceptionally bushy and thick goatee, I don't imagine there's much effect.

[jpfed]

They trained this model on Youtube videos. I'd be surprised if whatever fine differences goatees may induce didn't get crushed away by Youtube's lossy compression.