Self-checkout machines cause 'stage fright' in shoppers

Do you ever use the self-checkout at your local store? And when you do, are you one of those fumblers who has to get a cashier to help? Or are you the annoying guy right behind, tapping his foot and sighing loudly?

A new study has found the fear of looking stupid stops people from using self-service checkout machines -- but hiding in a crowd helps. And that could give stores some tips on how to handle self-checkout, which is becoming a very popular cost-cutting tool among retailers.