Ruby has quite a bit of syntax (parens, methods on objects, blocks, etc), whereas scheme has almost none (parens, special forms like lambda, #t, '()).
Of course both have less obtrusive syntax than Java, which requires the famous
public static void main...
just to get started. That is the kind of stuff that I think confuses true beginners. They look at that stuff and think "holy crap memorize these voodoo incantations" and never really leave that mindset once they get there. Even if they eventually learn what static means, they will always treat it as such.
I think once they get the hang of programming in something, it's easy to build up from there. I just think it causes people to focus on the wrong thing (syntax rather than semantics) when they are first starting out.