It could mean she's confused or thinking hard about something.
Maybe she's frustrated and can't figure out a solution. Or, it could just be a random gesture for added character expression.
Maybe she's confused or trying to remember something.
Maybe he's confused or trying to remember something.
Maybe it's confused or trying to figure something out.
Maybe he's confused or trying to figure something out.
Maybe he's confused or trying to figure something out.
Maybe he's confused about something and can't figure it out.
Maybe he's confused about something and can't figure it out.
Maybe he's confused or trying to figure something out.
He could be having a moment of indecision or facing a problem that's making him scratch his head. It might be that he's lost in thought, trying to come up with a solution.
Maybe she's confused or trying to think of something.