The world can be chaotic. Cars whiz by on the road. People walk past you. There may be birds and planes flying overhead. Despite all of this potential confusion, you manage to make sense of most of what is happening around you. The ability to comprehend the world reflects an interaction between the things you see around you and your beliefs about the world.
An interesting question is the degree to which your beliefs influence what you are seeing in the moment. This question was explored by Christos Bechlivanidis and David Lagnado in a fascinating paper in the August, 2013 issue of Psychological Science.
They created a simple computer-based environment in which basic shapes (like squares and rectangles) could move and influence each other. By playing with the environment for a while, participants could learn how the various objects worked. For example, when a green square collided with a barrier, it caused the red rectangle to become a star. The blue square would only allow squares, but not other shapes to enter its borders. So, in order to get the red rectangle inside the blue square, the green square had to collide with the barrier first.
In one study, some participants were given a series of exercises in this computer environment so that they learned how the objects acted. Eventually, they learned how to get the red rectangle inside the blue square. A second group got no training.
Afterward, participants saw a video of the objects moving in the world. In this video, the red rectangle entered the blue square about 100 milliseconds before the green square hit the platform. The red rectangle turned into a star after the green square hit the platform. All of this happened in the same spatial position, so that participants could see all of the objects without having to move their eyes.
The participants then described the order of events in the test video and gave information about why the events happened in that order. Those who received no training generally saw the events happen in the order in which they happened in the video. They recognized that the red rectangle turned into a square before the green square hit the platform and that the rectangle became a star after it entered the blue square. When asked, they said that this was the order they saw the events.
The participants who received training were much more prone to describe the events in the order that fit with their training. They reported that the green square hit the platform before the rectangle turned into a star, and that the rectangle turned into a star before it entered the blue square. They were also likely to say that this ordering happened, because that reflects the way the environment works.
At one level, it should not be surprising that we have to use a lot of conceptual knowledge to help us make sense of what happens in the world. Causal relationships do not often change that quickly, and so it is valuable (most of the time) for our beliefs to influence our interpretation of what we see.
However, this influence of belief on behavior can be a problem in situations like eyewitness testimony. It is well known that the reports of eyewitnesses are not that reliable. If people perceive events in a way that is consistent with how they believe that the world works, then their reports of the order of events in a complex situation may be wrong. Because groups of people are likely to share causal beliefs, even entire groups may see events in the wrong order, so having multiple witnesses who provide corroborating testimony about the order of events does not necessarily mean that the events happened in that order.