Surprise is the emotion that arises when an individual comes across an unanticipated situation. Sudden and involuntary surprise usually lasts a fraction of a second. A surprise can be a positive, neutral or negative experience.
A certain facial expression is characteristic of surprise. The most predictable signal is the raising of the eyebrows. Eyebrows curve and rise, as the eyelids open wide, and the forehead wrinkles. The relaxed jaw drops, exposing a parted upper lip and teeth. The impact of a surprise is measured by how much the jaw drops. In terms of bodily posture and vocalization, surprise is characterized by hands that fling upwards and a variety of gasps and sighs.
The momentary expression of surprise is usually followed by another emotion, like fear or happiness, which reveals emotion toward the feeling of being surprised or the surprising object. Being mugged, for example, is an unexpected ordeal. After the initial moment of surprise, the victim feels fear.