Social facilitation is when someone is able to perform in a different way, based upon being around others. Keeping in mind that others are watching you or are around you can motivate you to perform a said task more correctly.
It can hinder because, let's say for instance that you are on stage and you are about to perform an act. Perhaps with the audience watching you it will give you stage-fright and will hinder your ability to perform better. Or, let's say your teacher is watching you perform on a quiz. Your teacher watching you may give you anxiety or it might make you nervous.
