When we tell stories about our lives, most of us never have our memories questioned. NBC's Brian Williams, like other high-profile people in the past, is finding out what happens when questions arise.

Williams's faux pas – retelling a story of his helicopter coming under fire in Iraq a dozen years ago when it was actually the helicopter flying ahead of him – was much like Hillary Rodham Clinton's during the 2008 presidential campaign. Her story was about coming under fire during a visit to an airfield in Bosnia 12 years earlier. George W. Bush also misremembered when, on several occasions, he told audiences that on 9/11 he watched the first plane fly into the north tower of the World Trade Center on TV, just before entering that classroom in Florida to read a book to school kids. In each case, these were highly emotional moments. Williams's helicopter made an emergency landing in the desert behind the aircraft that was hit; Clinton was made to don a flak jacket and was told her airplane might not be able to land at the airport in Bosnia because of sniper fire in the area; and Bush was told by an aide about the first crash into World Trade Center just before entering the classroom.

That each of those memories was false created huge public relations headaches for Clinton and Williams. But the fact is that false memories are not that uncommon, especially when they involve highly emotional events.

Brian Williams, the anchor and managing editor of NBC Nightly News, has apologized for telling a story about coming under fire during a reporting assignment in Iraq in 2003. The Post’s Erik Wemple describes what Williams got wrong and the potential impact on his reputation and career. (Gillian Brockell/The Washington Post)

Scientists have been telling us for years that memory of autobiographical events, also known as episodic memory, is pliable and even unreliable. The consensus from neuroimaging studies and laboratory experiments is that episodic memory is not like replaying a film but more like reconstructing an event from bits and pieces of information. Memories are stored in clusters of neurons called engrams, and the proteins responsible for storing those memories, scientists say, are modified and changed just by the reconstruction process of remembering.

These findings are just one reason that last year, the U.S. National Research Council recommended that the criminal justice system exert tighter control over the use of eyewitness testimony in court and come up with a more scientific approach to the identification of suspects in police lineups.

Using neuroimaging, Northwestern University scientist Ken A. Paller was able to offer one reason that people can misremember something as important as being shot at or a terrorist attack. Paller determined which parts of the brain were activated in forming a false memory and which when forming a real memory. The finding: The part of the brain that perceives an object or event overlaps with the part that imagines an object or event.

Even scientists who specialize in memory research are susceptible to misremembering.

Several years ago, University of Illinois psychologist Daniel Simons performed an experiment on himself by first writing down everything he could remember about his own experiences on 9/11, beginning with hearing about the planes crashing into the twin towers. He then asked the people who were with him at that time to write down their own recollections. Later he discovered that two of the people he asked were, in fact, not with him at the time. And he did not remember one person who was there.

The experiment made Simons empathize with Clinton and Bush.

"The next time you hear a politician or celebrity make a false claim about what they remember,” he wrote in 2010, “keep in mind that they might not be lying maliciously. They might not even realize their memory is wrong (and if you tell them, they might not believe you).”

But Williams, Clinton and Bush also could have simply been lying, not misremembering. Research also tells us that people by and large act, think (and yes, even remember) in a way that is beneficial to themselves. Everyone lies to gain an advantage of some kind, but we lie in little bits so that we can still feel good about ourselves. Dan Ariely, a behavioral economist who wrote the book “The (Honest) Truth About Dishonesty: How We Lie to Everyone -- Especially Ourselves” put it this way: “People may allow themselves to cheat sometimes, but not if it involves identifying themselves as Cheaters.”

Read more: