A critical concern about eyewitness memory is the sometimes tenuous relationship between the accuracy of a witness’s memory and his confidence in it. In general, if you have seen something before, your confidence that you have seen it and your accuracy in recalling it are linked: The more confident you are in your memory, the more likely you are to be right. But new research reveals important nuances about this link.

In a paper published earlier this year, the cognitive psychologists Henry L. Roediger III and K. Andrew DeSoto tested how well people could recall words from lists they had studied, and how measured they were in their recollections. For words that were actually on the lists, when people were highly confident in their memory, they were also accurate; greater confidence was associated with greater accuracy. But when people mistakenly recalled words that were similar to those on the lists but not actually on the lists — a false memory — they also expressed high confidence. That is, for false memories, higher confidence was associated with lower accuracy.

To complicate matters further, the content of our memories can easily change over time. Nearly a century ago, the psychologist Sir Frederic Charles Bartlett conducted a series of experiments that mimicked the “telephone” game, in which you whisper a message to the person next to you, who then passes it along to the person next to them, and so on. Over repeated tellings, the story becomes distorted, with some elements remaining, others vanishing, and entirely new details appearing.

When we recall our own memories, we are not extracting a perfect record of our experiences and playing it back verbatim. Most people believe that memory works this way, but it doesn’t. Instead, we are effectively whispering a message from our past to our present, reconstructing it on the fly each time. We get a lot of details right, but when our memories change, we only “hear” the most recent version of the message, and we may assume that what we believe now is what we always believed. Studies find that even our “flashbulb memories” of emotionally charged events can be distorted and inaccurate, but we cling to them with the greatest of confidence.

With each retrieval our memories can morph, and so can our confidence in them. This is why the National Academy of Sciences report strongly advised courts to rely on initial statements rather than courtroom proclamations: A witness who only tentatively identifies a suspect in a police station lineup can later claim — sincerely — to be absolutely certain that the defendant in the courtroom committed the crime. In fact, the mere act of describing a person’s appearance can change how likely you are to pick him out of a lineup later. This finding, known as “verbal overshadowing,” had been controversial, but was recently verified in a collective effort by more than 30 separate research labs.

The science of memory distortion has become rigorous and reliable enough to help guide public policy. It should also guide our personal attitudes and actions. In Dr. Tyson’s case, once the evidence of his error was undeniable, he didn’t dig his hole deeper or wish the controversy away. He realized that his memory had conflated his experiences of two memorable and personally significant events that both involved speeches by Mr. Bush. He probably still remembers it the way he described it in his talks — but to his credit, he recognizes that the evidence outweighs his experience, and he has publicly apologized.

Dr. Tyson’s decision is especially apt, coming from a scientist. Good scientists remain open to the possibility that they are wrong, and should question their own beliefs until the evidence is overwhelming. We would all be wise to do the same.