12/04/2013 02:54 pm ET | Updated Feb 03, 2014

I'm Not Making This Up: Why I'm Skeptical of Eyewitnesses

One of the major disconnects between those who practice effective skepticism and those who believe in paranormal possibilities (or are emotionally invested in unexplained mysteries) is over the topic of anecdotes and witnesses' testimony.

If there is one fact that I wish we could all accept early in life, I would vote for drumming in the idea that memory is not like a tape recorder. If we learn this truth about the human mind, we could avoid so much trouble.

Memory is constructed. Pause a moment and let that sink in.

Memory is not objective, it is constructed by our own brains. It is not burned, or ingrained, or seared into it, as much as we would like to think that is the case. The truth is less precise, uncertain, and disturbing.

Most of us rely on our short- and long-term memories nearly every moment of the day. For the most part, our recollections are simple and good enough to get us through situations and day-to-day activities without much trouble, but false memories are ubiquitous.

I don't trust my memory at all. I've seen it fail epically. That's why I try to keep logs and records of what happened and when. I'll take pictures of things I want to remember and write copious notes.

I've had a journal since I was 7. There have been times when I looked back on events and was dumbfounded at the dispute between what I thought had happened and what I wrote happened in my journal. For a moment, I doubt my journal! But that's incorrect. My current memory had evolved into what I wanted it to be for my state right now. It had been reconstructed each time I accessed it in the intervening years.

I'd bet many of you think you have a great memory -- that you can relate your observations clearly and accurately. But you're wrong, too. Don't feel bad about this! We are all imperfect when it comes to observing and remembering. Our brains are incredible things but they function mostly for self-preservation and propagation of the species, and only moderately well as an accurate memory collector.

Several paranormal subjects such as hauntings, UFO sightings, and Bigfoot reports rely solely on witnesses' recollections. Sometimes years or decades pass, but the memory is still taken as credible and true because the people seem sincere. I've lost count of how many times the argument has been put to me that the eyewitness reports for Bigfoot are so compelling and voluminous that there must be something to them. Frequently, they present the really poor argument that if this was a court of law, Bigfoot would be ruled genuine. It's more complicated than that.

Not only are our memories generally far from perfect, perception is poor too. Our recollection of scary or traumatic events under less than ideal conditions (like seeing a large creature in the woods) are exceptionally prone to construction and reconstruction based on what we believe or anticipate can be true. We only take in so much detail and our brains fill in the rest. We make so many mistakes, yet we don't even realize it. Our brain feeds back this story that we accept is accurate. It's the best we've got.

Some of the most egregious examples of memory failure (and worse, fabrication of false memories) was during the time in America's history known as the Satanic Panic period of the 1980s. Many people were accused of heinous crimes relating to Satanic ritual abuse in homes, day care facilities, and schools. Scores of innocent people were convicted on testimony from witnesses who felt certain they were telling the truth about being tortured or seeing torture of others. These convicted people went to jail for decades. Their lives were destroyed. Their families were decimated.

It is too difficult for me to imagine sitting in jail, convicted of a terrible crime that just didn't happen and not being able to do anything about it. Witnesses lied -- they didn't even know they lied. They believed those false memories really happened due to manipulative psychotherapy procedures that created a story out of whole cloth. It is too easy to warp a memory into something different, wrong or fantastic, but this is done repeatedly, daily, and can cause great harm.

Here are two heartbreaking stories of people convicted for Satanic crimes that never happened:

In November 2013, four San Antonio women imprisoned for sexually assaulting two girls in a Satanic-related ritual in 1994 were freed from jail after a judge agreed that their convictions were tainted by faulty witness testimony. [More]

Also in November 2013, Frances Keller was released from jail 21 years after being sent to prison along with her husband Dan for the alleged sexual abuse of 3-year-old Christy Chaviers in a day care setting. A media investigation showed that police and prosecutors were too credulous in believing children's stories relating impractical and impossible abuse despite the lack of solid evidence to suggest any crime ever happened at all. Dan will also be freed. [More]

These are just two cases of the many hundreds or thousands of cases where innocent people were convicted based on faulty memory. It's not justice. It's not right.

One of the main characteristics of good skepticism about claims is awareness of how easily we fool ourselves. Memory is something that is so often wrong that we have to face up to the reality that stories and witness accounts are the worst kinds of evidence upon which to base your conclusion.

So, this is why I can't take your Bigfoot story or any of your recollections at face value and why it would be unskeptical and irrational of me to do so. It's not personal. It's human.

Memory is not like a tape recorder -- not mine, not yours, not anyone's. This is well-established. Stories are unreliable. You need to have better evidence than eyewitness testimony to back up your claim.

For more, I recommend the book Eyewitness Testimony by Elizabeth Loftus, a world-leader in memory research. Dr. Loftus has been working with experts in the legal field to develop guidelines for jurors regarding how to think about eyewitness testimony in court cases.