Professor and Chair, Department of Linguistics, University of Sydney; Author, The Utility of Meaning
Verbal Overshadowing

Suppose that two people witness a crime: one describes in words what they saw, while the other does not. When tested later on their memories of the event, the person who verbally described the incident will be worse at later remembering or recognizing what actually happened. This is verbal overshadowing. Putting an experience into words can result in failures of memory about that experience, whether it be the memory of a person’s face, the color of an object, or the speed that a car was going. This effect was discovered by the psychologist Elizabeth Loftus and her students in experiments exploring witness testimony and the malleability of human memory. The stakes are high. As Loftus has shown, imperfect memories can—and often do—put innocent people behind bars. Our memories define much of what we take to be real. Anything that interferes with memory interferes, effectively, with the truth.

The idea that describing something in words can have a detrimental effect on our memory of it makes sense given that we use words to categorize. To put things in the same category is, by definition, to set aside any information that would distinguish the things from each other. So, if I say “She has three dogs,” my act of labeling the three animals with the single word “dog” treats them as the same, regardless of likely differences in color, size, or breed. There are obvious advantages to words’ power to group things in this way. Differences between things are often irrelevant, and glossing over those differences allows us to reduce effort in both speaking and understanding language. But the findings of Loftus and colleagues suggest that this discarding of distinguishing information by labeling something in a certain way has the effect of overwriting the mental representation of the experience. When words render experience, specific information is not just left out, it is deleted.

Through verbal overshadowing, your words can change your beliefs, and so choice of words is not merely a matter of style or emphasis. And note that the effect is not just an effect of language, but always of a specific language, be it Arabic, German, Japanese, Zulu, or any of the other 6000 languages spoken in the world today. The facts of linguistic diversity suggest a striking implication of verbal overshadowing: that not just different words, but different languages, are distinct filters for reality.