What are the most obvious traits of people with a lower level of cognition?

I have a testing method with a very high accuracy rate.
I’ll tell them a counterintuitive viewpoint—for example: drinking hot water actually hurts your stomach more than drinking cold water. Then I explain the underlying principle.
Human body temperature is around 36.5°C, while the lowest temperature for thermal burns from low temperatures is 44°C. That means if an object above 44°C contacts the skin for a long time, it will cause damage.
But the issue is that water can be swallowed, yet you also feel that the temperature is too hot—about 60°C.
When drinking hot tea in winter to warm up, the water temperature can even approach 70°C.
This means that when you feel warm and comfortable in your stomach, your stomach mucosa and esophagus are actually at a temperature above what they can tolerate.
On the other hand, over the long course of human evolution, people have basically been eating cold food; drinking a bit of cold water is not really a problem—your stomach isn’t that fragile.
At this point, observing their reaction lets you judge their cognitive level.
People with high cognition don’t find it hard to accept a new viewpoint. Because they can rely on common sense to judge whether the new viewpoint is reasonable, they quickly realize that humans are homeothermic animals, with a body temperature of 36.5°C. Anything higher than this temperature entering the body, in theory, requires the body to pay an additional cost to regulate it.
When they hear “60°C water goes into the stomach,” they immediately understand that it’s far above body temperature, and that it really could be a problem.
People with low cognition react emotionally first.
Why? Because what you say causes cognitive dissonance.
What is cognitive dissonance? It means two conflicting cognitions coexist in their brain at the same time.
Cognition A: “Drinking hot water is good, it warms the stomach, and it’s the wisdom passed down from generation to generation.”
Cognition B: “Drinking hot water might hurt your stomach.”
When these two cognitions clash, they feel uncomfortable. How do you get rid of that discomfort?
People with high cognition choose to adjust the cognitive framework and think again, thereby correcting their viewpoint.
People with low cognition choose to “eliminate” the information that makes them feel uncomfortable, directly denying you.
Typical lines include:
“Bullshit. People drink hot water generation after generation—so you’re saying it hurts the stomach?”
“The traditional wisdom of Chinese medicine for thousands of years—what do you know?”
“I just love drinking hot water. I’ve done it for decades, and I’m doing great!”
They rebut your basis not with logic, but with emotion and anger.
To them, “the information that makes me uncomfortable” and “the wrong information” are the same thing. Any challenge to the viewpoint they already hold is an offense to them, not an enlightenment.
Musk said the most common mistake people make is “Wishful Thinking,” meaning desire-based thinking.
Most people don’t judge the world according to “what is true”; they judge according to “what I want to be true.”
When you tell someone “hot water might hurt the stomach,” you challenge their cognition and make them uncomfortable. They will immediately get angry, furious.
Because this conclusion implies that their habits over the past decades might have been wrong—meaning they need to change and rebuild a whole cognitive framework. For them, the mental energy required to process this conflict is too high; their limited brainpower can’t take on that task.
So, instinctively, they activate a mechanism to deny your viewpoint, protect their old cognition, and bring their brain back to a “comfortable state” with no conflict.
Therefore, if you want people with low cognition to accept a viewpoint, you can only follow their way of thinking to fabricate a lie that fits their cognitive model—not explain logic, not provide evidence.