Research by Gregory Berns (2001) shows that the human brain is not only looking for the unexpected, it actually craves the unexpected. Berns used a computer-controlled device to squirt either water or fruit juice into people’s mouths while their brains were being scanned by an fMRI device. Sometimes the participants could predict when they were going to get a squirt, but other times it was unpredictable. The researchers thought that they would see activity based on what people liked. For example, if people liked juice then they would see activity in the nucleus accumbens area of the brain. The nucleus accumbens is the part of the brain that is active when people are experiencing pleasurable events.

https://www.blog.theteamw.com/2011/03/02/100-things-you-should-know-about-people-69-your-brain-craves-surprises-2/