Uncertainty

An aversive state that people are motivated to reduce arising from the lack of information about an event.

Reference:
Matsumoto, D., & Hwang, H.S. (2012). Evidence for a nonverbal expression of triumph. Evolution and Human Behavior, 33(5), 520–529. https://doi.org/10.1016/j.evolhumbehav.2012.01.005