When our understanding of cause-and-effect is contradicted by what we actually see, sometimes our understanding overrules our perception.

Research published online in Psychological Science on June 26 found people’s causal expectations influenced their perception of the ordering of events in time.

“It appears that when people hold strong convictions about the relationships between objects or events, then inference takes precedence over perception,” Christos Bechlivanidis of the University College London, the lead author of the study, told PsyPost.

The study of 229 participants, co-authored by David A. Lagnado, found the temporal content of perception is strongly biased by our understanding of causality. Bechlivanidis and Lagnado discovered people perceptually reorganized events in time so that the presumed cause preceded the effect — even after witnessing the effect precede the cause.

“We usually assume that we see the objective temporal order in which events take place especially when we directly witness those events,” Bechlivanidis explained.

“However, apart from the information that is delivered through our senses, there is another way to constrain the possible orderings of events, by relying on the way events are related with each other. Since causes happen before their effects, certain orderings must be impossible or at least highly improbable. Surely, the glass must have collided with the floor before shattering to pieces. You must have flicked the switch before the room was illuminated.”

“Nevertheless, one would assume that we rely on our senses first and foremost and use such causal knowledge when no sensory input is available, i.e. when we’re not looking, when we’re absent or distracted,” Bechlivanidis continued. “Our two experiments provide evidence against this view.”

For their study, Bechlivanidis and Lagnado created a software-based game that contained various 2-D objects that could be activated by the user. The objects each behaved in predefined ways, which the user had to figure out through trial and error. They learned, for instance, that the collision of a green square caused a red rectangle to transform into a star.

Once the user learned how the various objects interacted, they watched one of two recorded video clips of the game. One clip violated the expected causal order of events, while the other did not. Those who watched the former clip tended to perceive events in the wrong temporal order.

“Despite having clearly witnessed the events happening at a very close distance to each other, our participants reported an order that matched not what they saw but what they thought it would be normal to see, i.e. they reported the presumed cause occurring before its associated effect,” Bechlivanidis said.

The researcher explained the study had three important implications.

“On the one hand, our results can be seen as further evidence pointing to the fact that what we call perception is heavily influenced by knowledge and inference; as a number of researchers have shown in the past, it appears that our sensory input goes through the editor’s room on its way to consciousness,” Bechlivanidis told PsyPost.

“Secondly, as philosopher Rick Grush has argued, what we experience at any given instant is not a single objective happening, a snapshot of the external world, but rather a collection of temporally neighbouring events, which are then ordered according to our knowledge.”

“Finally, our results provide evidence regarding the importance of causal information in human cognition. It appears to be the case that people are not only sensitive to the causal relationships of the world and the temporal information embedded in those relationships, but, furthermore, that they sometimes rely on that information and disregard the objective sensory input,” Bechlivanidis concluded.