The expectancy effect is a psychological phenomenon that plays a significant role in paranormal investigations. It refers to the way in which people's expectations influence their perceptions and behaviours, especially in situations where the outcome is uncertain.

If someone expects to find experience a ghost or paranormal activity at a location, they are more likely to interpret ambiguous incidents as proof of the supernatural. For example, an unexplained noise or a vague image captured on camera might be deemed a ghostly encounter if the person is anticipating paranormal activity.

The expectancy effect is related to another psychological principle called confirmation bias, which also influences how we perceive and interpret information, but the expectancy effect operates in a slightly different way. While the expectancy effect leads individuals to experience outcomes that align with their initial expectations, confirmation bias involves a broader tendency to seek out, interpret, and remember information in ways that affirm...