I'm not aware of any formal studies, if you mean that. The easy example I usually use is asking you, as a human, to fold a paper into 10 equal pieces without any tools to assist you in measurement; then try folding into 16 equal pieces. This demonstrates that even though you have (presumably) grown up with decimal, you can
still work better with tonal in practice. If you don't want to waste 2 papers,
http://www.intuitor.com/hex/switch.html has a Java applet demonstrating the same in software (but for hexadecimal, which shares this same benefit as tonal).
If you want to teach people what essentially amounts to counting in binary, start an education reform agenda. Persuade teachers to teach the binary code to young children. Until then, leave Bitcoin alone with it. This is wholly impractical nonsense, and you should not pollute Bitcoin with it. I think the world would benefit greatly if kids could natively count in hex, but this is a frivolous attempt to make that happen.
The purpose of Bitcoin is to offer the world a competing store of value, not to compel them to switch to count in hexadecimal and to use a foreign language for doing so. This is a world where the vast majority of its inhabitants are completely comfortable counting in base ten. Kudos to Satoshi for defining base-ten fractions as the de facto fraction for Bitcoin.