Plenty of webmasters do not link out for selfish or strategic reasons.....
... but the web is all about linking. That is why they call it "the web".
I link out a lot. I believe that it makes my pages richer information sources. I believe that it builds credibility.
If you were a visitor would you prefer a page that has no links or the same page that links out to information sources, sites with great information on directly related subjects? Which of those would be recommended more via tweets, links, likes, emails?
So, my vote is that google gives credit for linking out and even if they don't your visitors will.