Writing in Forbes, psychologist Todd Essig says it's perfectly plausible that Brett Kavanaugh has no recollection of what to Christine Blasey Ford was a life-changing event:
It is distinctly possible that his lack of memory is not because it never happened but because he really has no recollection of it taking place. He never encoded the event. Therefore, he cannot remember something he never noticed, even though it proved to be life-altering for someone else.
As Dr. Richard Friedman wrote this week, an attack usually triggers intense emotions and stress hormones that facilitate encoding memories. That is why “you can easily forget where you put your smartphone or what you had for dinner last night or last year. But you will almost never forget who raped you, whether it happened yesterday — or 36 years ago.”
Of course, this doesn’t let [Kavanaugh] off the hook for what he did or at all suggest he either has or doesn’t have the qualities one needs in a Supreme Court Justice. It’s just that he may not be lying about what he recalls. It also doesn’t excuse the self-serving way he transformed the absence of memory into the presence of certainty that something didn’t happen. A judge should know better than to rest his career on such a logical incongruity.
For another take on this phenomenon, check out Deborah Copaken's moving essay in The Atlantic, "My Rapist Apologized."