- "She is able to tell if a person is lying."
- ―Entry on Maggie's gift [src]
Maggie can sense if a person is lying within her presence.
Maggie can sense a lie by being in close proximity to someone. 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 automatically.
Maggie can only sense when someone is lying, without necessarily sensing the reason for it or the intentions of the liar.
This power also has a side effect, as any kind of deception makes her physically uncomfortable.
When Maggie was human, she always knew when a person was lying with their words, which compelled 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 - she was well aware that her parents did not love her as much they did her siblings.
By becoming a vampire, she proved a good asset to them: no lie has ever escaped her detection. Her lie detection was intensified, allowing her to read people's lies not just by their words, but also by movements and facial expressions, though any deception made her physically uncomfortable as a side-effect to the change.
Maggie found herself well-fitted in the coven because Liam and Siobhan were always truthful to her and to each other.
- "... She had a gift for knowing when she was being lied to, and her verdicts were never contested."
- ―Bella's description of Maggie's talent[src]
When Maggie and her coven is approached by the Cullens' cry for help, Maggie senses their honesty and agrees to be their witness against the Volturi. Even after Alistair - one of the witnesses - fled for fear of the Volturi, Maggie remains determined to stay behind and help protect the truth.
During the Volturi confrontation, when Aro tells Renesmee he has no desire to hurt her family, Maggie hisses at his lie.
- "Charles can sense when someone is lying to him."
- ―Entry on Charles's gift[src]
Charles can sense whether a person is lying to him. It has not been explained how different from Maggie's this gift is, but it appears to be less pronounced than hers.
Charles developed the power to detect lies after his transformation to vampire. In late 2006, Charles and his mate, Makenna, are approached by the Volturi's offer to witness their punishment on the Cullens; he senses no dishonesty from their behalf and so agrees to their wishes.
- "It is not what I see, but what I feel. Garrett said they have ways of knowing lies. I, too, know when I am hearing the truth, and when I am not."
- ―Charles's description of his power.[src]
When they arrive in Forks with the Volturi to question the Cullens' doing, Charles senses the Cullens' honesty in their testimony, being falsely blamed for a crime they did not commit, and also newfound dishonesty from the Volturi. He gives his witness and then leaves with his mate, hoping to avoid a chaotic outcome.
- Aro's ability 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.
- In the Black and Uley packs, all members' minds are connected to each other when they are in wolf forms, allowing them to read each other's thoughts. This enables a degree of teamwork unimaginable otherwise and essential in collaborative activities requiring high coordination, like hunting or battle, or when the pack is spread over vast areas. No privacy exists in the team. When a pack member shifts his allegiance to another Alpha, his mental connection with the previous pack breaks, to reform with the new one. It is interesting to note that Alphas in telepathic connections can control the thoughts they share.
- Edward Cullen's ability of telepathy allows him to read people's minds from a distance, which serves as a means to secure if they were telling the truth about something.