Written by Veronica Welles on Quora.
Yes they can. If you make them sit through the logic and reasoning part of the IQ tests, their score will not show any noticeable outliers. In other words, they score the same as you and I.
Of course, the higher functioning the narcissist, the higher their logic and reasoning scores are, which means high functioning narcissists are ostensibly more logical than the average person.
But, the problem with all narcissists is that they have fragmented, unstable personalities.
That means you are not really dealing with one person. While they are short of having multiple personality disorder, their many masks, habitual disregardance of reality, truth, or anything they find inconvenient means their character is highly erratic and inconsistent. Highly erratic, to put it mildly.
They’ve also never introspected ever in life. Introspection for our minds is equivalent to hard disk defragmentation. A form of mental clearing and sorting of memory and personality, a way to bring things back into harmony and agreement. When this has never been done, fragmentation can continue unchecked until you effectively get the human equivalent of lost clusters, data loss.
This makes narcissists functionally psychotic and functionally have multiple personality disorder. It’s all just at sub-clinical levels, so it’s hard to identify and detect, just like the VCR that only malfunctions while at home, and always works fine at the repair shop.
Scott M. Peck calls it ambulatory schizophrenia. It’s sub-clinical, meaning it’s not obvious, except for bouts which usually occur in private, behind closed doors. Narcissists usually take care to appear as sane and logical as possible while at work or in public. They very carefully maintain masks of sanity.
Although in written tests and interviews, narcissists can come across every bit as logical and rational as the next applicant, at their core, what’s truly inside the narcissist, is a psychotic person, with so many disconnected masks, and so little life reflection and introspection that there’s actually nobody real in there who can actually interface with real reality, just many masks and urges fighting for dominance behind a disingenuous facade.
You can effectively say that for a narcissist, there no real self, and no real reality. Everything is an illusion, a fragmented disjointed funhouse of crazy mirrors.
No matter how high the narcissist scores in logic tests, when they periodically snap (due to their invisible narcissist cycles) and become psychotic, you have a person who is capable of feats of mental and emotional insanity that beggars belief. But only their loved ones get to witness that. Most people never get to catch even a glimpse of this, and so not only do outsiders not know that the person is a narcissist, they would often claim that the person is a highly logical, highly rational person who thinks carefully, and they might even throw in the obligatory ‘wouldn’t hurt a fly’ comment.