Why do the other Cyclops fail to help Polyphemus when they respond to his cries for help in the Story the Cyclops?

Odysseus cunningly told the cyclops, Polyphemus, that he was named "Nobody". As a result, when Polyphemus was screaming in horrible pain after Odysseus (Nobody) stabbed him with a stake in the eye, the neighboring cyclopes yelled to Polyphemus to see if he needed help. Polyphemus responded that Nobody was attacking him.