Ive been watching shows on tv: why is it women tend to doubt their abilities or put themselves down?

So they get other people to tell them how great they are. Either because they like the attention and like to feel good or because they need other people's feedback to know where they stand. Women seem more cautious about appearing arrogant - one, because they don't want to be hypocritical having called someone else arrogant, and two, because it's more important for them to be liked.