An electronic device displays a first user interface that corresponds to a first application, and detects on a touch-sensitive surface a first gesture that includes movement of a contact in a respective direction on the touch-sensitive surface. In response to detecting the first gesture, the device, in accordance with a determination that the movement of the contact is in a first direction, replaces display of the first user interface with display of a second user interface that corresponds to a second application; and in accordance with a determination that the movement of the contact is in a second direction, distinct from the first direction, displays a first system user interface for interacting with a system-level function.