Special Counsel Robert K. Hur’s report, in which he declined to prosecute President Biden for his handling of classified documents, also included a much-debated assessment of Mr. Biden’s cognitive abilities.

“Mr. Biden would likely present himself to a jury, as he did during our interview with him, as a sympathetic, well-meaning, elderly man with a poor memory.”

As an expert on memory, I can assure you that everyone forgets. In fact, most of the details of our lives — the people we meet, the things we do and the places we go — will inevitably be reduced to memories that capture only a small fraction of those experiences.

It is normal to be more forgetful as you get older. Broadly speaking, memory functions begin to decline in our 30s and continue to fade into old age. However, age in and of itself doesn’t indicate the presence of memory deficits that would affect an individual’s ability to perform in a demanding leadership role. And an apparent memory lapse may or may not be consequential depending on the reasons it occurred.

There is forgetting and there is Forgetting. If you’re over the age of 40, you’ve most likely experienced the frustration of trying to grasp hold of that slippery word hovering on the tip of your tongue. Colloquially, this might be described as ‘forgetting,’ but most memory scientists would call this “retrieval failure,” meaning that the memory is there, but we just can’t pull it up when we need it. On the other hand, Forgetting (with a capital F) is when a memory is seemingly lost or gone altogether. Inattentively conflating the names of the leaders of two countries would fall in the first category, whereas being unable to remember that you had ever met the president of Egypt would fall into the latter.

Over the course of typical aging, we see changes in the functioning of the prefrontal cortex, a brain area that plays a starring role in many of our day-to-day memory successes and failures. These changes mean that, as we get older, we tend to be more distractible and often struggle to pull up the word or name we’re looking for. Remembering events takes longer and it requires more effort, and we can’t catch errors as quickly as we used to. This translates to a lot more forgetting, and a little more Forgetting.