1. A method, comprising: at an electronic device with a touch-sensitive surface and a display, wherein the device includes one or more sensors to detect intensities of contacts with the touch-sensitive surface: displaying a plurality of selectable user interface objects in a first user interface on the display; detecting a contact at a location on the touch-sensitive surface while a focus selector is at a location of a first selectable user interface object, in the plurality of selectable user interface objects, on the display; and, while the focus selector is at the location of the first selectable user interface object on the display: while the contact has been continuously detected on the touch-sensitive surface for a first duration, detecting an increase in a characteristic intensity of the contact to a first intensity threshold; in response to detecting the increase in the characteristic intensity of the contact to the first intensity threshold, blurring a subset of the plurality of selectable user interface objects with a first magnitude of blurring, while maintaining display of the first selectable user interface object without blurring the first selectable user interface object, wherein the subset of the plurality of selectable user interface object includes two or more of the plurality of selectable user interface objects in the first user interface other than the first selectable user interface object; after blurring the subset of the plurality of selectable user interface objects and while the contact has been continuously detected on the touch-sensitive surface for a second duration that is longer than the first duration, detecting that the characteristic intensity of the contact continues to increase above the first intensity threshold; and, in response to detecting that the characteristic intensity of the contact continues to increase above the first intensity threshold, dynamically increasing the magnitude of blurring of the subset of the plurality of selectable user interface objects with a second magnitude of blurring that is greater than the first magnitude of blurring, while maintaining display of the first selectable user interface object without blurring the first selectable user interface object; after increasing the magnitude of blurring of the subset of the plurality of selectable user interface objects without blurring the first selectable user interface object, detecting a decrease in the characteristic intensity of the contact and while the contact has been continuously detected on the touch-sensitive surface for a third duration that is longer than the second duration; and, in response to detecting the decrease in the characteristic intensity of the contact, dynamically decreasing the magnitude of blurring of the subset of the plurality of selectable user interface objects to a third magnitude of blurring that is less than the second magnitude of blurring, while maintaining display of the first selectable user interface object without blurring the first selectable user interface object, wherein: the first magnitude of blurring has a first blur radius; the second magnitude of blurring has a second blur radius that is larger than the first blur radius; and the third magnitude of blurring has a third blur radius that is smaller than the second blur radius.