We all know people who seem to be naturals at taking standardized tests: They sit down and whiz through it. They may not be the kids with the best grades, but they earn a top score anyway.

And we all know people who worry before the standardized test, then sit down and sweat their way through it. They may be seen as the smartest kids in their class, but their score leaves something to be desired.

It could well be that brain chemistry is to blame, and this post explains how and why it happens. It was written by Ned Johnson, founder, president and tutor-geek of PrepMatters, a tutoring service in the Washington region, and co-author of “Conquering the SAT: How Parents Can Help Teens Overcome the Pressure and Succeed.” He is also the co-author of “The Self-Driven Child: The Science and Sense of Giving Your Kids More Control Over Their Lives.”

By Ned Johnson

It’s the season for gifts and joy, travel and overwhelm, and — at least for children and parents of a certain age — for PSAT scores. This week, juniors and sophomores (and even a few freshmen) who took the PSAT in October are now able to access their scores online. For most, the scores will elicit a “meh” as they spend their time and attention on other things. For some, it will be like an early present. For others, a small grenade of despair.

The PSAT is offered by the College Board to help prepare students for the SAT. Along with the ACT, the SAT is a tool used by many college and university admissions officers to assist in selecting students, based in part on the ability of these tests to predict first-year college grades. Originally, students took the SAT once and never even saw their scores; only colleges did.

Then the College Board spent decades promulgating the SAT as something akin to an IQ test, and it took on great cultural power. People who perform well on tests such as the PSAT believe (sometimes with a narrow conception of “intelligence”) that it shows how smart they are. People who do not perform well on such tests believe (sometimes fearfully or angrily) that it doesn’t. Kids especially may want to scream out, “I am not a test score!”

As a test-prep geek for more than 25 years, I have seen that both can be right. The reason? Brain chemistry.

In 1936, Hungarian endocrinologist Hans Selye introduced the concept of stress as we use it today. (Some might argue that the College Board beat him by a decade with the 1926 launch of the SAT.)

Selye discussed both eustress and distress, levels of stress hormones that can improve or hinder performance. Our performance improves with increasing stress, perceived as excitement, but only to a point, beyond which performance suffers. We all have a peak point, deemed optimal arousal, and where that peak falls is very individualized. What is thrilling for you may be overwhelming for me, or just enough to excite me is frankly boring for you.

These differing levels have a big impact on our performance, especially our executive functions of planning, organizing, decision-making, problem-solving, controlling our attention, and mental and emotional flexibility. Executive functions are the work of the prefrontal cortex, making possible “mentally playing with ideas; taking the time to think before acting; meeting novel, unanticipated challenges; resisting temptations; and staying focused.”

The challenge, as neuroscientist Amy Arnsten describes it, is that the prefrontal cortex is like “the Goldilocks of the brain.” Our prefrontal cortices need things to be “just right” to work optimally — sufficiently challenging without being threatening.

Many a student has looked on in dismay as some “slacker” who seems to barely engage in school rocks the SAT, leaving more-studious and high-achieving classmates slack-jawed or teary: “They got that on the PSAT! How is that possible? It’s so unfair! Did we even take the same test?”

As it turns out, some people underperform with more pressure, while others overperform. Depending on how the brains of different students process stress and brain chemicals such as dopamine, it is indeed like taking different tests.

Chun-Yen Chang, director of the Science Education Center at National Taiwan Normal University, looked at a specific gene (COMT) of “worriers” and “warriors,” folks whose prefrontal cortices either process dopamine efficiently or inefficiently.

Worriers, who need only a little stress to be on their game and are more academic and studious, can easily underperform under the perceived pressure of a high-stakes test. Warriors, in contrast, often overperform, the pressure perceived as excitement. For the latter, perceived stress helps; for the former, it hobbles.

What to do, then, if you have a worrier who is staring at her results with a box of tissues?

Start with practice

As neuroscientist Adele Diamond noted, “While the studies are ongoing, the early results show those with worrier genes can still handle incredible stress — as long as they are well trained.” She also said that one of the best solutions for worriers is as simple as more practice, with some stress. In fact, shielding them from worry could be the worst response, depriving them of the chance to acclimate to recurring stressors.

Decrease the perceived threat

Parents, coaches and counselors can decrease the sense of threat the student feels by helping to dispel myths about these tests and also about college and life success. Moreover, both the SAT and ACT allow kids to know and control their scores. The College Board allows score choice, which nearly all colleges follow, permitting kids to submit just what they want. And many colleges “super-score,” giving kids the benefit of their best score and sweeping aside scores from an off day. Similarly, the ACT even allows students to delete scores permanently from their record, giving students ultimate control of their scores. Another way to decrease a sense of threat is to visit FairTest, the website of the nonprofit National Center for Fair and Open Testing, to see the more than 1,000 colleges that are test-optional. One of my students just got admitted by early decision to Wake Forest, which doesn’t require a standardized test for admission. Meanwhile, he continued to prepare for last Saturday’s ACT. Knowing that he had a Plan B increased his motivation.

Decrease your own stress

While stressed kids stress parents, the inverse is also true. Be a non-anxious presence.

Reflect on what is or was going on with your kids when they were taking the test

Many people think that cognition is like a light switch, there when you want it at the same wattage, day or night. Far from it. It’s not just stress that can impair thinking and performance. Again, Diamond observes of executive functions: “If you’re sad or stressed, lonely, sleep-deprived or not physically fit, executive functions will be the first to suffer and will suffer the most.”

Love your kids unconditionally

Act as if you do not know PSAT scores are coming. Look past the PSAT to the holidays, and the coming of a brand-new year. First, you deserve the freedom to enjoy your kid, regardless of what score he or she has. And, second, loving kids unconditionally helps move them into the middle of the performance curve, improving their performance. Whether they rocked the test or got rocked, your child is not a test score.