It is related to the startle response experienced by animals and humans as the result of an unexpected event.
Surprise is included as a primary or basic emotion in the taxonomies of Carroll Izard and Paul Ekman.
According to these perspectives, surprise is evolutionarily adaptive, and also innate and universal across human cultures.
When the rules of reality generating events of daily life separate from the rule-of-thumb expectations, surprise is the outcome.
[1] This gap can be deemed an important foundation on which new findings are based since surprises can make people aware of their own ignorance.
The main function of surprise or the startle response is to interrupt an ongoing action and reorient attention to a new, possibly significant event.
Studies show that this response happens extremely fast, with information (in this case a loud noise) reaching the pons within 3 to 8 ms and the full startle reflex occurring in less than two tenths of a second.
More recent research shows that raising of the eyebrows does provide facial feedback to disbelief but not to the startle.
Expectations of verbal language that may lead to surprise may include but are not limited to, expletives, shouts, screams, and gasps.
This does not necessarily mean that an individual, for instance, will not be surprised during the jump scene of a scary movie, it implies that the individual may expect the jump scene due to familiarity with scary movies, thus lowering the level of surprise.