An electronic device with a touch-sensitive surface, a display, and one or more sensors to detect intensity of contacts: displays a plurality of user interface objects in a first user interface; detects a contact while a focus selector is at a location of a first user interface object; and, while the focus selector is at the location of the first user interface object: detects an increase in a characteristic intensity of the contact to a first intensity threshold; in response, visually obscures the plurality of user interface objects, other than the first user interface object, while maintaining display of the first user interface object; detects that the characteristic intensity of the contact continues to increase above the first intensity threshold; and, in response, dynamically increases the amount of visual obscuring of the plurality of user interface objects, other than the first user interface object.