Update: In an interview with Reuters published on Wednesday, Trump seemed to mention the cognitive test his doctor had performed. We’ve updated this article as a result.

On its surface, the Montreal Cognitive Assessment (MoCA) test seems pretty easy. Can you draw a three-dimensional cube? Can you identify these various animals? Can you draw a clock? Can you repeat back the phrase, “The cat always hid under the couch when dogs were in the room”?

The test, which can be seen here, assigns a certain number of points to each of these tests and an overall score it tallies out of 30 possible points. On Tuesday, President Trump’s doctor — the White House physician who also cared for Barack Obama — reported that Trump had scored perfectly, 30 points out of 30, after asking for the annual exam to include some sort of test of mental function. (That request was pretty clearly a response to the torrent of questions about Trump’s mental acuity that were raised, in part, by anecdotes from Michael Wolff’s book “Fire and Fury.”)

If you look at the test, it’s pretty hard to see how you could not score a 30. You see a picture of a lion and have to identify it as a lion? That old joke about how the elderly and toddlers are subject to the same indignities seems pertinent here: Is this really the bar that needs to be met to demonstrate full mental capabilities?

Well, according to those who study dementia and other mental deterioration, yes.

In 2009, I spent six months serving on a jury in the state of New York that was asked to judge the guilt or innocence of a man named Anthony Marshall. Marshall was the son of Brooke Astor, a New York socialite and heiress to the much-diminished Astor fortune. If you’ve ever traveled to New York, you’ve encountered the name: Astor Place, the Waldorf-Astoria or the Astoria neighborhood in Queens. Marshall was accused of having taken advantage of Astor’s diminished mental state to change her will without her being aware of the changes made. Ultimately, the 12 members of the jury found Marshall guilty of several charges.

Over the course of that trial, we were presented with a great deal of information about how doctors assess the mental capabilities of a patient. This was critical to the prosecution; were they not able to prove that Astor’s mental state was diminished, it undercut their argument that Marshall had acted without his mother’s consent. As such, expert witnesses testified about their personal examinations of Astor and others spoke to the reliability of the tests.

Central to that case was one of the components of the MoCA test: drawing a clock. Astor was asked repeatedly to draw analog clocks as a test of her mental acuity. On more than one occasion, she was unable to do so properly.

Astor’s clock. (Pace University)

Consider how you draw a clock. You have to plan ahead to ensure that the numbers are all positioned properly: The 12 at the top, the 6 at the bottom. You need to position the hands correctly, depending on their size. In Astor’s clocks, she didn’t even get that far. On one, she started at 1 and worked her way around clockwise, but spaced the numbers incorrectly, with 5 landing at the bottom of the circle. The 10, lacking space, was placed outside the circle. In another test, she was simply unable to complete the clock after beginning to number it in the wrong direction.

Studies have shown that this test can be used to spot problems with the brain’s executive functioning even before other signs of mental decline are apparent. There are questions about the proper scoring method and about the extent to which educational differences may be apparent, but, generally, there’s a reason that the test is included.

Astor was also subjected to another mental test that shares characteristics with the MoCA: the Mini-Mental State Examination (MMSE). The MMSE includes tests such as counting backward from 100 by multiples of seven and asking the subject to recall words presented shortly beforehand. In one test, she scored a 21, proving unable to spell “world” backward or to follow simple commands. But still: Only 9 points off despite her diminished capacity.

The point is not that the test is easy. The point is that an inability to complete aspects of the test reveals different types of mental decline. The clock test is about executive brain function: memory, planning ahead. The different parts of the MoCA are labeled according to what they test, with the clock test falling under “visuospatial/executive.” Questions about the current year and date are under “orientation.” The request to identify a drawing of a camel is under “naming.” In the test’s scoring instructions, it explains what is covered: “attention and concentration, executive functions, memory, language, visuoconstructional skills, conceptual thinking, calculations and orientation.”

It is, as Trump’s doctor noted, a tool for identifying early signs of mental deterioration, like the mental version of a blood sample on which your doctor runs a battery of tests. It’s not the SAT; it’s a screening device. Imagine a disease in which you suddenly were unable to say the letter H. Singing the alphabet song is a trivial task that kindergartners do, but if you suddenly stumbled over the letter that follows G, your doctors might take that as a sign that the H illness was present. It might also be an error, of course, but that’s the point. It’s a test of a particular thing that for everyone else is easy.

Yes, Trump passed with flying colors, as any adult with normal cognitive function probably would. And that’s the point. There’s every indication from Tuesday’s report that Trump maintains normal cognitive function. That he passed the test is just like you successfully singing the alphabet song. Sure, it’s easy — unless you have that can’t-say-H disease. Here, the MoCA test is easy — unless you have the sort of impairment that Trump was said to have suffered by any number of public critics.

You’re supposed to get 30 out of 30 — and when you don’t, that’s when the doctors learn something.

Update: This was all well and good until Trump himself made reference to his MoCA score in an interview with Reuters.

“[Trump] blamed his three immediate predecessors, Bill Clinton, George W. Bush and Barack Obama, for failing to resolve the [North Korea] crisis and, a day after his doctor gave him a perfect score on a cognitive test, suggested he had the mental acuity to solve it.”

“‘I guess they all realized they were going to have to leave it to a president that scored the highest on tests,’ he said.”

The original post above was meant to explain to readers why the seemingly easy nature of the test was not a reason that Trump’s passing it should be pooh-poohed. After all, the lingering question was one of Trump’s cognitive abilities and whether or not he was affected by the early stages of mental decline, perhaps in the form of dementia. Mocking as easy a test meant to detect that particular thing is as dumb as mocking someone for passing a blood test.

But the flip side of this is that this is not a test you should brag about — any more than you should brag about passing a blood test. Not only did Clinton, Bush and Obama have no idea how Trump would perform on such a test, but neither they nor anyone else should see Trump’s perfect score on the test as indicating anything other than “this person’s brain is not showing obvious signs of deterioration.”

Trump loves numbers that he can spin as being good, so it was perhaps predictable that he’d start bragging about his perfect score on the MoCA. The original post was meant to explain why Trump shouldn’t be mocked for having performed well on what, to a person with a normally-functioning brain, is an easy test. But if one wishes to point out the folly of bragging about doing well on such an easy test, feel free.