An electronic device with a display, a touch-sensitive surface, and sensors to detect intensity of contacts with the touch-sensitive surface displays, on the display, an affordance corresponding to respective content at a respective size and detects a gesture that includes an increase in intensity of a contact followed by a subsequent decrease in intensity of the contact. In response to the increase in intensity, the device decreases a size of the affordance below the respective size. In response to the subsequent decrease in intensity: when a maximum intensity of the contact is above a content-display intensity threshold, the device ceases to display the affordance and displays at least a portion of the respective content; and when a maximum intensity of the contact is below the content-display intensity threshold, the device increases the size of the affordance to the respective size and forgoes displaying the respective content.