Detecting Digitally Altered Video

A study in Applied Cognitive Science finds that we're likely to believe a doctored video over own memories of an event. Christie Nicholson reports

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[Below is the original script. But a few changes may have been made during the recording of this audio podcast.]

The last few years have seen digitally altered photos land in numerous media outlets. Modern technology is making it tough for even the expert to spot a fake. But imagine if a doctored image lands in court and even sways eyewitnesses, who had seen the event in question?

Evidence from a study published in the journal Applied Cognitive Science shows that people will believe a videotaped version of an event, even if it differs from the reality they lived through.

Sixty subjects participated in a gambling game, where they’d make bets on getting the answer to a trivia question right. All subjects had another player seated next to them. Except the “other player” was really a researcher.

Later, a video of the gambling session was doctored to make it seem that the other player—the researcher—had cheated.

A third of the subjects were told that the person next to them MAY have cheated. Another third were told the player next to them was caught on camera cheating. And the rest were shown the fake footage of the other player cheating. Then all were asked to sign a statement only if they had seen the act of cheating take place.

Just 5 percent of the control group, who were merely told about the cheating,  signed the statement. 

Only 10 percent of the group who were told that the cheating had been caught by cameras—but did not actually see the video—signed the statement.

But nearly 40 percent of those who saw the fake video signed. And another 10 percent signed after being asked a second time by the researcher.

With ever-new digital tricks, we need to be aware that seemingly ironclad evidence may in fact be altered.  And find our way to the truth by employing one of our most valuable resources: a healthy skepticism.  

—Christie Nicholson

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