Yeah, he’s had three centuries to learn how people work. He reads people like a book–look at how quickly he taps into what makes Emma run in S1, and then surmises her feelings regarding Nealfire in S2. He’s good at it, and I think that’s experience rather than seeing abilities. He was always intelligent, too, but I think it’s having a chance to test people and experiment on them for a couple centuries that’s made him so good at predicting their behaviors.
Keeper of Belle's Gold magic, sand dollar, cloaks, purple FTL outfit, spell scroll, library key, copy of Romeo and Juliet, and cry-muffling pillow, Rumple's doll, overcoat, and strength, and The Timeline. My spreadsheet: https://drive.google.com/file/d/0B6r8CySCCWd9R0RUNm4xR3RhMEU/view?usp=sharing