In some embodiments, an electronic device optionally identifies a person's face, and optionally performs an action in accordance with the identification. In some embodiments, an electronic device optionally determines a gaze location in a user interface, and optionally performs an action in accordance with the determination. In some embodiments, an electronic device optionally designates a user as being present at a sound-playback device in accordance with a determination that sound-detection criteria and verification criteria have been satisfied. In some embodiments, an electronic device optionally determines whether a person is further or closer than a threshold distance from a display device, and optionally provides a first or second user interface for display on the display device in accordance with the determination. In some embodiments, an electronic device optionally modifies the playing of media content in accordance with a determination that one or more presence criteria are not satisfied.