Lie detection

Lie detection is Maggie's and Charles's ability to sense if someone is lying to them.

Maggie
"She is able to tell if a person is lying"

- Entry on Maggie's gift

Maggie can automatically sense if a person is lying to her or to someone in close proximity. A person didn't have to speak for her to know if he or she was behaving in a way contrary to their beliefs. If anyone misrepresented themselves in either appearance or action, Maggie could feel it.

However this also has a side effect, as any kind of deception made her physically uncomfortable.

Breaking Dawn
When the Cullen family call Maggie's coven to Forks for assistance, Maggie senses the truth coming from their words and decides to help them face the Volturi.

Origin
When Maggie was human, she always knew when a person was lying with their words, compelling her to always point out the lie. This made others feel uncomfortable around her as they could never lie in her presence, prompting her parents to leave her behind when they immigrated to America.

Charles
"Charles can sense when someone is lying to him."

- Entry on Charles's gift

Charles can sense if a person is lying to him or not. It has not been explained how different from Maggie's this gift is, but it appears to be less pronounced than hers.

Breaking Dawn
When Charles and his mate, Makenna, arrive in Forks on behalf of the Volturi, Charles determines that the Cullens are in fact innocent, being falsely blamed for a crime they did not commit.

Similar abilities

 * Aro: His power of tactile telepathy allows him to read people's minds and determine if they were telling the truth as well as access to every thought they ever had.
 * Edward Cullen: His power of telepathy allows him to read people's minds to secure if they were telling the truth about something.