By Jonny Lupsha, News Writer

Purported Bigfoot DNA samples were recently revealed to be of deer hair, according to NBC News. The news came as the FBI declassified a wealth of documents pertaining to mythical creatures. The way we use critical thinking can affect our belief or disbelief in stories like this.

NBC News reported that Peter Byrne, now 93 years old, contacted the FBI several times in 1976 requesting they test the DNA of several animal hairs believed to belong to the legendary creature known as Sasquatch or Bigfoot. The resulting evidence concluded that the hairs belonged to several deer that were native to the area in which they were found. Belief and doubt are both powerful forces, but sometimes a healthy dose of skepticism can refute, refine, or even enhance our beliefs.

Errors in Thinking

We’re capable of making many mistakes as we process cognitive thought. “Flaws in logic are one example,” said Dr. Steven Novella, Assistant Professor of Neurology at the Yale School of Medicine. “We call these logical fallacies—we tend to make logical connections that are not valid, that are not real.” The Online Writing Lab at Purdue University lists the logical fallacies we use in thinking and provides some examples that may sound familiar. One is the Ad hominem fallacy, which attacks the character of a person with whom we disagree rather than disproving their claims—such as “your concerns on this issue must be unfounded because you’ve fallen for false alarms before.” Another is the straw man fallacy, which oversimplifies and/or exaggerates someone’s standpoint to make them sound bad—like saying someone who makes a single poor dietary choice clearly doesn’t care whether they die of a cardiovascular disease.

Dr. Novella went on to say that we also make a lot of false connections when we think. “Our heads are filled with facts—things that we know to be true, but in fact are false,” he said. “Either they’re just out and out wrong or they’re just assumptions that may or may not be true but we really don’t know.” He explained that our memories are also flawed, despite our trust in them to fairly represent and depict events of the past.

The Process of Critical Thinking

Keeping a healthy scientific skepticism about surprising events plays into critical thinking, which is at least a five-step process. Dr. Novella said the first step is to examine all the premises or facts that you believe are true, looking for any cracks in the armor, so to speak. Second, you’ll want to objectively examine your logic and make sure you aren’t using any logical fallacies or cutting corners because you wish to arrive at a specific conclusion.

Third, “Critical thinking also means thinking through the implications of a belief—that different beliefs about the world should all be compatible with each other,” Dr. Novella said. “We have a tendency to compartmentalize, to just have one belief walled off from all our other beliefs, and, therefore, we insulate it from refutation.” Fourth, he recommended checking with others regarding your belief due to the fact that any one person’s experiences are limited and sometimes subconsciously biased. “When a large consensus on a specific claim is achieved, there’s probably a greater chance that that consensus reflects reality [rather] than the process of just an individual,” he said.

Finally, and perhaps most difficult, be comfortable with uncertainty. Dr. Novella said there are some things we simply cannot know right now, despite our logic and evidence to support a belief.

Consciously avoiding errors in our thought processes and undergoing a steady, systematic practice of critical thought are two ways to separate the wheat from the chaff, so to speak. When debating the existence of creatures like Bigfoot, these can come into play to help us decide what we personally believe.

Dr. Steven Novella contributed to this article. Dr. Novella is Assistant Professor of Neurology at the Yale School of Medicine. He earned his M.D. from Georgetown University and completed his residency training in neurology at Yale University.