Defintion

“An emotion typically resulting from the violation of an expectation or the detection of novelty in the environment” (American Psychological Society, 2022).

Surprise represents the difference between expectations and reality. That can mean something happening that is not expected or something not happening that was expected.

Surprise and the startle reflex

Although rare, a sudden unexpected event may trigger an immediate and involuntary startle reflex directly affecting information processing capability and situational awareness, which can last for some time and have implications for the affected individual's decision making ability. In such a situation the affected individual may act irrationally.