Smart spectacles able to detect electrical activity in the brain include a display unit, a camera, a brain central detection unit, and a processor. The camera can shoot an image of currently-watched content. The brain central detection unit can detect current of user's neuronal cell in the brain. The processor can accordingly determine whether user is excited by what he is watching. When the user's neuronal cell is not excited, the processor controls the camera to shoot image including currently-watched content, analyze the content in the image, and regard such content as a first searched object. The processor searches for target content corresponding to the first searched object from a database, and displays the target content on the display unit.