“Image-based forgery is becoming more common not least because humans seem to be particularly vulnerable even to obvious fakes.”
“Schetinger and co began by assembling a set of faked images from three forensic image databases. The resulting set was made up of 177 images, of which 97 were forged either by erasing some element from the picture or adding one.
The team then asked 393 people to decide whether an image had been forged and if so, to click on the region in question. These people were all well-educated but with no special expertise in forgery detection. That produced over 17,000 responses.
The results show just how poor humans are at this task. “Our results indicate that people show inaccurate skills at differentiating between altered and non-altered images … only identifying the modified images 46.5 percent of the time,” they say.
That’s only marginally better than chance. And the team’s observations about the results are not more comforting. They say there was no general conclusion over which forgeries were the hardest to detect—even the most explicit forgeries were missed by some people.
The team asked these people why they had missed the forgery and received a range of excuses, from the image being too cluttered or that they simply did not examine that part of the image. In itself, these answers might be interesting tips for forgers.
The bottom line is that forged images are hard for humans to spot. And that means we are all at risk of being fooled by forgeries like those that enthralled Australia in 2010.
Ref: arxiv.org/abs/1509.05301 : Humans Are Easily Fooled by Digital Images”