“If You See Something, Say Something.” But What Did You See?

Here’s How Eyewitness Mistakes are Made and What Police Dan Do to Prevent Them

Joni E. Johnston, Psy. D.
5 min readFeb 1, 2022


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“If you see something, say something.” That’s a powerful message, one that encourages all of us upstanding citizens to come forward and help police prevent or solve crimes. Things that, in years past, you might have thought were none of your business.

Once criticized for raising their eyebrows over eyewitness accounts, even law enforcement seems to have had a change of heart. Their plea for the public to step forward after Gabby Petito disappeared led to two vacationers unearthing photos of the van in which she and her fiancé, Brian Laundrie, were living. These pictures led to the location of Gabby’s body.

Eyewitness accounts are the backbone of evidence; we trust few things more than what appears before our very eyes. But how do you know if you’re right and if what you’re seeing is accurate? And what if you’re wrong? A review of wrongful convictions, many involving eyewitness testimony, has sparked some serious heart-searching as well as a slew of bills aimed at preventing faulty testimony behind them.

The power of the eyewitness

Anyone who works in the courtroom knows that eyewitness testimony can be a powerful weapon for justice or the jester in a comedy of errors. Several recent high-profile stories show you just how badly things can go when mistakes happen. We read statistics like this:

Eyewitness misidentifications are known to have played a role in 70 percent of the 349 wrongful convictions which were overturned based on DNA evidence.

There’s another wild card: the malleability of memory. Research has shown that, in certain circumstances, a person can falsely remember committing a crime that was actually committed by someone else. Memory can be contaminated by a number of things-suggestion, time, erroneous information, drugs/ alcohol.

Some of these wrongful convictions have been so scarring that you might wonder if we should just give up on eyewitness testimony. But don’t throw the baby out with the bathwater.



Joni E. Johnston, Psy. D.

Forensic psychologist/private investigator//author of serial killer book. Passionate about victim’s rights, the psychology of true crime, and criminal justice.