[Spero Mcgee]

Originally Posted by Kyutetsuki

Not to burst your bubble, but women's breasts vary in size throughout their lives, with weight gain, weight loss, pregnancy and various hormone influxes. It's probably just people like us, into this thing, that would solely notice the gains and filter out the parts that don't fit into our preferences.

I think there's a psychological term for it, but I forgot what it's called.

I usually just call it a fetish, there might be some fancy/scientific name for it but when it comes down to it, it's just a fetish.
As far as documentation goes, you could take a look through photo albums of friends and what not.
Or become a doctor like you sometimes see in anime that does yearly pysical examinations.
Other then than that you would have to be very close to some one to document it very early on.