I am, unfortunately, an expert on memory. I am not a doctor, or a researcher, but a traumatic brain injury (TBI) survivor. Like many people who suffer a traumatic brain injury, my memory was severely affected. I have no memory of the accident that caused my TBI, no memory of the months leading up to the accident (known as retrograde amnesia), and continuing memory problems to this day. Sometimes I'll remember an event, sometimes I won't. Since I was a journalist before the accident, I have used my journalistic skills to research and learn all I can about the complex subject of human memory.

So I was fascinated over the past two days to watch the story play out about Brian Williams, who said he “misremembered” an event in Iraq in 2003, when he claimed to be in a helicopter that was hit by RPG fire. The problem for Williams is that he made this claim not once, but numerous times during the past 12 years, and being a public figure, most of those times were caught on videotape. He was finally called out by soldiers and airmen who were there, and remembered things quite differently than Williams.

What is really going on here? There is no doubt that human memory is fallible and malleable; many recent studies and experiments have shown that eyewitness accounts can be wildly unreliable. Not only do people not remember things, but they can often combine memories in ways that are not true, or even make things up. In psychology, this is known as confabulation: a memory disturbance that produces imaginary or distorted memories about oneself or the world. Confabulation is distinguished from lying in that there is no conscious intention to deceive and the person is unaware the memory is false.

The big question here is this: Is Brain Williams lying or confabulating? If he is outright lying, then his credibility as a journalist is gone and he should be fired. If he is confabulating, then he is doing what many of us do without even knowing we do it, and he is just being human. Is there any way for us to know? Probably not. Only Brian Williams really knows what is going on in his brain, and even he may not know. Williams said he “spent much of the weekend thinking I‘d gone crazy,” as he tried to sort out how his memories had gotten jumbled.

That part rings true to me. I spent several years after my accident often thinking I was going crazy, as I struggled to remember events, or as events seemed to run together in my mind. As my brain healed, those moments thankfully grew fewer and farther between, but they were still extremely anxiety producing.

There are other parts of Williams story, however, that give me pause. At one point several years after my accident I was discussing my memory problems with my neurologist, and asked him why I could remember some things so clearly, while other memories either eluded me entirely, or got all jumbled up. "We really don't know why people remember some things and not others," he replied. "It's one of the great mysteries of the brain. We think it may have something to do with the natural, atavistic human instinct for survival. If your brain thinks a particular memory is important for keeping you alive, then it will remember it clearly."

Of course in the modern world what constitutes survival is not nearly as easy to determine as when we were dodging wild animals on the plains of Africa, so our brain can't always tell the difference between events that are crucial and those that are not. Is remembering a fight with your ex crucial to your survival? That depends. Are you going to end up in court over it? Will it affect your finances? Your children? Or just be an annoyance?

One would think that getting shot at in a helicopter would constitute an event that would be remembered as crucial to one's survival, and would be something Williams would remember clearly. There is also the problem that he made up very specific details, such as the claim he made on Late Night with David Letterman that “our captain took a Purple Heart injury to his ear in the cockpit.” That part of the story also appears to be untrue.

Why would he make this stuff up? It is human nature to embellish, inflate and exaggerate all for the sake of a good story. We usually make a joke out of people's propensity to do this, the most well-known example being the tendency of fishermen to tell “whoppers” and stretch the size of their catch. One of the best books and movies to examine this phenomena in recent years was Big Fish, about a son who had trouble believing his father's seemingly tall tales.

If Williams is lying, there are many possibilities: low self-esteem, psychopathology, habit and others. If he is confabulating the possibilities are also many: stress, time, even images seen on video, certainly a workplace hazard in his occupation. Many of us “remember” events from our childhood, for example, when what we are really remembering are our parent‘s home movies we viewed years later.

Whatever it is, I doubt Brain Williams is a compulsive, pathological liar. He wouldn't have gotten to the top of his profession and gained the trust of millions if that were so. One way or another, his mind is not acting in rational, predictable ways. In this age of computers we sometimes forget that the human mind is not a digital machine, it is an organic, constantly changing organ, with all the problems that entails. So perhaps we should have compassion for Brain Williams, while being thankful that we are all only too human.