Keeping your goal to yourself or looping other people in on it doesn’t give you the same edge, says study author Howard Klein, Ph.D., professor of management and human resources at the Ohio State University in Columbus. You'd get the benefits from telling a friend who has run a 3:30 marathon that you're training for that time, too—but not from sharing that info with a marathon virgin.
One reason this strategy works: Chances are, you’ll want to impress, not disappoint, the people you look up to. That desire immediately increases commitment.
The bottom line:
If no one you know has achieved your goal, choosing someone whose opinion you value is just as good, Klein says.