Over time I’ve come to appreciate that feature of the iMac that asks its users, “Are you sure you want to permanently erase the items in the Trash?”

To underline the importance of this question, the iMac adds this reminder: “You can’t undo this action.”

I’ve been using Macs long enough to know the consequences of the action. That’s why the computer’s nagging inquiry occasionally annoys me, usually when I’m in the grips of a frenzy brought on by a mess of files that seem to have created themselves . . . for no reason that I can recall. So into the trash they go!

Then comes the question . . . and the reminder (which treats Trash as a proper noun).

IN FAIRNESS, I admit this reminder sometimes prevents mistakes. Unfortunately, more times than not, my trash reflex is quicker than my brain and — ooops! — items are erased before I’ve reconsidered.

But the subject here is not the trash reflex; it’s that other thing — the brain: Wouldn’t it be nice if it alerted us when certain things in our memory bank were about to be forgotten . . . and did we wish to prevent this?

But no, the brain erases items all the time . . . like where did we hide all of those passwords we’ve been forced to create since we entered the electronic age? Or what's the date of our wedding anniversary? And why am I standing in front of the refrigerator? All the answers were erased by my brain without the courtesy of a consultation.

MOST AT RISK are words seldom used. Since I was never was much interested in cars, there’s a whole vocabulary that my brain may have put in a foreign language file — words such as “alternator,” “carburetor,” “voltage regulator,” “camshaft,” “distributor,” “differential” and “intake manifold.” I had to look them up in a thesaurus while writing this piece.

God’s solution, obviously, was the creation of the word “thing,” which the brain never forgets. Indeed, in an emergency it’s the first word the brain sends you. As in, “All I know is my car won’t start. It must be because the thing is broken . . . you know, that thing that turns the car on. Maybe all I need is a new thing.”

I figure the brain has to dump a load of words, names, dates and telephone numbers whenever it approaches an information overload.

I’m frequently reminded of that scene in the entertaining Cary Grant-Audrey Hepburn movie “Charade,” when Grant’s character tries to make the acquaintance of Hepburn’s Regina Lampert. But she turns him away with the film’s most-quoted line: “I already know an awful lot of people and until one of them dies I couldn’t possibly meet anyone else.”

(To which he replies, “Well, if anyone goes on the critical list, let me know.”)

AND SO it must be that our brains cannot process new data until it discards some of the old. Perhaps that’s why I’ve always had trouble remembering names, especially of people I meet at social gatherings. My brain knows I won’t ever see most of these folks again, so why bother storing their names?

All of this was on my mind recently after I went through my nightly ritual of stepping through the television channels to find an excuse to avoid going to bed. Like many couples, my wife and I started watching television separately when we acquired our first remotes. I believe this is a necessary step to insure the survival of your marriage. Otherwise the relationship becomes a constant battle for control of the device that determines what programs you watch. Let’s face it, everyone likes to click from channel to channel, but our methods — and our quests — are usually in conflict.

There I was at 1:30 a.m. When I arrived at Turner Classic Movies I found “Smile,” a 1975 spoof of beauty pageants. I hadn’t seen it in maybe 30 years, so I decided to linger awhile. It was kinda funny, but I was less interested in plot than I was in identifying some familiar faces.

SO I PICKED UP to consult my favorite memory restorer — the Internet Movie Database (imdb.com). Among the “Smile” credits was a name that faintly registered, which meant my brain hadn't completely erased my Denise Nickerson file.

Obviously, I turned to Google, but only after I tried to retrieve the name from my brain (which responded with a lie: “File not found”). The only image I came up with on my own was one I knew to be incorrect — Denise Nicholas, the actress from TV’s “Room 222,” who later was featured opposite Carroll O’Connor in the series, “In the Heat of the Night.”

I paused to consider the strange workings of the brain. How could mine have misfiled Denise Nicholas? During the run of “Room 222” I had a huge crush on her and even I interviewed her in the early 1970s. I spent an afternoon with the actress . . . and my brain didn't care.

Yet Kim Darby, Darby Hinton and Chuck Hinton remain in my brain’s database. Why? I don’t know. Hell, until I saw a “Magnum, PI” rerun a few months ago I didn’t even know if Darby Hinton was a man or a woman. (Man, it turns out.)

So when you speak of a riddle, wrapped in a mystery, inside an enigma, you could be describing the brain.

WIKIPEDIA'S article prompted me to recall Denise Nickerson from a 1971 television movie, “The Neon Ceiling.” Nickerson was cast as the 12-year-old daughter of a runaway wife played by Lee Grant, who won an Emmy for her performance. And, yes, Grant delivered a wonderful performance, but Nickerson stole the film, which ended with the girl stealing her mother’s car and driving off all by herself.

Later she would be considered for movie, “The Exorcist,” but that role went, of course, to Linda Blair. A few years later Nickerson retired from acting. Apparently she’s now an accountant in Denver.

In the meantime my brains continues to mess with me without permission. If you'll excuse me, I've got to go to the kitchen. But I don't know why.