Psychologists from the US, New Zealand and France have found that the way we initially think about the emotions of others biases our subsequent perception (and memory) of their facial expressions.
Thus, once people interpret an ambiguous or neutral look as angry or happy, they later remember and actually see it as such.
The study "addresses the age-old question: 'Do we see reality as it is, or is what we see influenced by our preconceptions?' Our findings indicate that what we think has a noticeable effect on our perceptions," said co-author Piotr Winkielman, professor of Psychology at the University of California, San Diego.
"We imagine our emotional expressions as unambiguous ways of communicating how we're feeling, but in real social interactions, facial expressions are blends of multiple emotions - they are open to interpretation. This means that two people can have different recollections about the same emotional episode, yet both be correct about what they 'saw.'
So when my wife remembers my smirk as cynicism, she is right: her explanation of the expression at the time biased her perception of it. But it is also true that, had she explained my expression as empathy, I wouldn't be sleeping on the couch," said coauthor Jamin Halberstadt, of the University of Otago in New Zealand,
"It's a paradox. The more we seek meaning in other emotions, the less accurate we are in remembering them," added Halberstadt.
The researchers pointed out that implications of the results go beyond everyday interpersonal misunderstandings - especially for those who have persistent or dysfunctional ways of understanding emotions, such as socially anxious or traumatized individuals.
Other applications of the findings include eyewitness memory-a witness to a violent crime, for example, may attribute malice to a perpetrator - an impression that researchers say will influence memory for the perpetrator's face and emotional expression.
The researchers showed experimental participants still photographs of faces computer-morphed to express ambiguous emotion and instructed them to think of these faces as either angry or happy.
Faces initially interpreted as angry were remembered as expressing more anger than faces initially interpreted as happy.
Interestingly, the ambiguous faces were also perceived and reacted to differently.
The researchers measured subtle electrical signals coming from the muscles that control facial expressions, and discovered that the participants imitated - on their own faces - the previously interpreted emotion when viewing the ambiguous faces again.
This means that when viewing a facial expression they had once thought about as angry, people expressed more anger themselves than did people viewing the same face if they had initially interpreted it as happy.
"The novel finding here is that our body is the interface: The place where thoughts and perceptions meet. It supports a growing area of research on 'embodied cognition' and 'embodied emotion.' Our corporeal self is intimately intertwined with how - and what - we think and feel," said Winkielman, of UC San Diego,
The study has been published in the journal Psychological Science.