In practicing the art of lying while retaining a hold on the allegiance of his base, Trump utilizes a propaganda principle—the Big Lie—best explained by Hitler. Now, please note that we are not equating Trump and Hitler; they are very different people. However, like Hitler, Trump is involved in the business of selling himself as an angry, righteous savior to the masses, resulting in a growing number of cultic devotees. So, it may behoove us to consider Hitler’s explanation of why the Big Lie is more successful than mere untruths. Here’s his explanation of the principle in Mein Kampf:
[I]n the big lie there is always a certain force of credibility; because the broad masses of a nation are always more easily corrupted in the deeper strata of their emotional nature than consciously or voluntarily; and thus in the primitive simplicity of their minds they more readily fall victims to the big lie than the small lie, since they themselves often tell small lies in little matters but would be ashamed to resort to large-scale falsehoods. It would never come into their heads to fabricate colossal untruths, and they would not believe that others could have the impudence to distort the truth so infamously. Even though the facts which prove this to be so may be brought clearly to their minds, they will still doubt and waver and will continue to think that there may be some other explanation.
Consider just two of many possible examples of the Big Lie: Trump’s bizarre claim that the military was out of ammunition when he took office and his equally bizarre claim that the father of Ted Cruz was involved with the assassination of Lee Harvey Oswald, adding, “It’s horrible.” It is the outrageousness of the Big Lie that a listener normally expects would create self-conscious awkwardness in the liar. In turn, this results in a need for a great liar to hide any nervousness that might give away the fact that he is attempting to deceive his audience. In poker, the failure to hide completely the lie inherent in a bluff is called a “tell,” the subtle behavior unwittingly exhibited when bluffing.
Self-deception in the Service of Deception
In 1976, one of us (RT) proposed the evolutionary theory of self-deception in the service of deception. This now well-established principle is simple: If one has the ability to eliminate conscious knowledge of one’s deceptions, that would also eliminate even a subtle tell. Thus, if a liar can deceive himself into believing he is telling the truth, he will be far more effective in convincing others.
This does not just occur in human interactions. For example, a male dog about to attack will puff up his body (raised hackles) and growl menacingly. It is not uncommon for a smaller, more aggressive dog to bluff a larger dog into retreating. In order for the bluff to be convincing, the snarling aggressor must show no sign of fear or doubt about the outcome. Any apprehension must be removed from awareness. Of course, if the display is not successful and a fight ensues, the canine assailant may end up running away yelping in fright, completely unable to hide overwhelming anxiety. But the possibility of successful intimidation will be maximized if the attacker appears to be fully ready to follow through with utter abandon, that is, if there appears to be no awareness in the aggressor that failure and retreat is even a remote possibility.
An important part of the adaptive basis for the evolution of repression consists of removing from consciousness any awareness of one’s doubts, anxieties, true motives, or aims when one is trying to deceive, intimidate, or just influence others. In 1984, Trivers’ notion of self-deception in the service of deception was then used by one of us (MS) to illuminate the adaptive function of psychological repression. Social relationships are fraught with conflict. If certain motives can be removed from consciousness, one can be far more convincing in complex social negotiations. In one episode of The Apprentice, Trump explicitly spelled out how this strategy works. Challenging his apprentices to sell high-priced art, he told them, “If you don’t believe it, if you don’t really believe it yourself, it’ll never work.”
Adaptive, Functional Psychopathy
When a person specializes in such predatory deception, we sometimes use the label sociopath, antisocial personality disorder, or narcissistic personality disorder. But the notion of a “personality disorder” suggests that Trump’s behavior is maladaptive or somehow inferior. If that were so and psychopathy were a defect (a negative, maladaptive mutation), it should have been wiped out by natural selection.
There is, however, a new science emerging regarding psychopaths, suggesting that they have been shaped by natural selection, meaning that their sociopathic behavior was selected because it was adaptive. While they are rare—1-2% of the population—they are successful at that frequency. Evidence? There is a “psychopathy scale” in which the higher you score the more likely you are to favor close relatives over more distant ones—exactly what you would expect natural selection to produce; they show a greater tendency toward psychopathic behavior the lower their relatedness to their victims. Furthermore, psychopaths tend to disperse farther from their places of birth, that is, to live among less related people where their predatory, interpersonal strategy is less likely to harm relatives. All this suggests that psychopathy can be a successful adaptation when the victims are not relatives. And the evidence in turn suggests they do indeed reproduce as well as normal people.
Consider Trump’s psychopathy. He is a most uncommon organism (1% or less) but has multiple wives and five children. They are successful. He supports them and may indeed love them. For a while, it even looked like Ivanka was being groomed for her own presidential run. (Lately, it looks like the Trump mantle is being passed to Junior.) In turn, Trump is notorious for favoring more closely related people over all others. Indeed, if black, they come from “shithole countries,” whether Haiti or African countries such as Obama’s Kenya. Muslims are to be excluded en masse. Mexicans are murderers and rapists.
If the behavior of psychopaths entails an evolving, adaptive evolutionary strategy, then they are setting up a co-evolutionary struggle with the rest of us. Since they are only at 1% frequency, they must have been subject to strong selection pressures whenever they appeared. But the rest of us only experience them 1% of the time. Therefore, we were not strongly selected to spot and resist them. In short, Trump could fly upside down at full speed toward us spewing nonsense and many of us would scarcely know what was happening, while this could merely be a display, his reality TV impersonation of a powerful, alpha male.
Self-deception and Narcissism
This may not, however, completely explain Trump’s uncanny ability to look an audience directly in the eye and lie. Trump seems to know that many of the things he says are not true. After all, he did go along with the characterization by Tony Schwartz (the guilt stricken and repentant, actual author of Trump’s “autobiography,” The Art of the Deal) of his many lies as “truthful hyperbole. So, he does seem to have some partial awareness that what he says isn’t always quite so. How then does Donald Trump avoid being seen as a liar by his base? Why is he so convincing to so many? Why don’t people spot the telltale signs indicating Trump’s awareness of his own lies?
The answer appears to be that for Trump there is only one reality, one truth: Donald J. Trump is the world’s greatest genius and he, and only he, can solve the problems we face. Yes, that does sound crazy. But that’s precisely the nature of narcissistic personalities; they have delusional beliefs about their own importance and greatness. For Trump, that is the only significant truth. Anything said in support of that truth is ... true. Like Hitler declaimed chanting the term Lügenpresse, Trump uses the same term to refer to any challenges to this great truth, “fake news.” There is no relevance to a correspondence notion of reality in which verbal descriptions of things must match empirical facts. The way things are has no importance if noting the reality would interfere in perceiving and promoting the One Great Truth.
Because of this, Trump consciously experiences no awkwardness when lying. Every word is judged against only one standard: Can this utterance convince my audience that they should support and follow me? If so, it is true (remember what the One Great Truth is). If not, it is false.
A Closer Analysis of Trump’s “Tell”
He has the kind of brilliance and charisma that is unique, rare, and captivating, although at times misunderstood. When he speaks one-on-one or to a crowd, you believe that you are the only star in his galaxy. 
Let’s look more closely at the self-deception Trump uses in order to deceive others. As with the growling dog, when Trump puffs himself up, he apparently eliminates any awareness of the possibility of failure. This is the narcissist’s sense of personal greatness and ability. It is self-deceptive in that Trump has only evidenced one truly superior talent: He is a highly competent, performance artist with a gift for reading his audience. Without any other special talent or ability, but with his willingness to break rules and deceive others, he has been able to parlay this one talent into some significant success as a fraudulent salesman, a reality TV star, and now President of the United States.
Nobody knows the system better than me, which is why I alone can fix it. (Trump accepting the Republican presidential nomination.)
It has become clear that Trump evidences the narcissist’s self-deceptive, grossly inflated self-appraisal. His endless swaggering knows no bounds. Just recently we learned that, in addition to his many extraordinary talents, he is an intuitive epidemiologist:
You know, my uncle was a great person. He was at MIT. He taught at MIT for, I think, like a record number of years. He was a great, super genius. Dr. John Trump. I like this stuff. I really get it. People are surprised that I understand it. Every one of these doctors said, “How do you know so much about this?” Maybe I have a natural ability. Maybe I should have done that instead of running for president.
In order to avoid experiencing any challenge to his grossly bloated sense of himself, this is what Trump must also self-deceptively blot out of awareness: Reality matters. What he said yesterday is often the complete opposite of what he said today and there is little reason to believe he won’t do a 180-degree turnaround tomorrow. The algorithm is simple, at the moment he speaks, he says whatever he believes will best promote his brand; his words need have no relationship to what he said in the past or will say in the future. Remember, he is a great genius, probably greater than Einstein. Therefore, he can set aside general reality theory and focus instead on his special theory of reality: Trump alone is here to save the day.
With the notion that reality matters effectively removed from his awareness, Trump never concerns himself with whether the words he speaks jibe with objective reality. He then experiences no trepidation about whether the things he says are actually true. This is the reason he is so convincing to the many people who comprise his base: Donald Trump has no tell.
 Thomas J. Barrack Jr., real estate investor, longtime Trump friend, and Chairman of Trump's Inaugural Committee. Quoted in A Very Stable Genius: Donald J. Trump’s Testing of America by Philip Rucker and Carol Leonnig, Penguin Press, 2020.
Daniel Kriegman, the former Chief Psychologist at the Massachusetts Treatment Center for Sexually Dangerous Offenders, is coauthor (with Malcolm Slavin) of The Adaptive Design of the Human Psyche: Psychoanalysis, Evolutionary Biology, and the Therapeutic Process. Dr. Kriegman has published extensively on the use of an evolutionary perspective in the theory and practice of clinical psychology, psychotherapy, and psychoanalysis. His most recent project is a book, Crusades, Jihads, and Genocides: An evolutionary understanding of the Holocaust, ISIS, and the human history of perpetual war and mass murder.
Robert Trivers, the winner of the 2007 Crafoord Prize in Biosciences for “his fundamental analysis of social evolution, conflict and cooperation,” developed the highly influential theories of reciprocal altruism, parental investment and sexual selection, parent–offspring conflict, and self-deception as an adaptive evolutionary strategy. Dr. Trivers has been called “the preeminent living evolutionist of our times” by the Los Angeles Review of Books. According to Steven Pinker, Trivers is “one of the great thinkers in the history of Western thought … the fields of sociobiology, evolutionary psychology, Darwinian social science, and behavioral ecology are in large part attempts to test and flesh out Trivers' ideas.” In 1976, Dr. Trivers first formulated the notion of self deception in the service of deception as a significant selective pressure shaping animal behavior.
Malcolm Slavin, a founder of the Massachusetts Institute for Psychoanalysis, is coauthor (with Daniel Kriegman) of The Adaptive Design of the Human Psyche: Psychoanalysis, Evolutionary Biology, and the Therapeutic Process. Dr. Slavin is an internationally renowned psychoanalyst with numerous publications applying an evolutionary perspective to depth psychology. He was the first to apply Robert Trivers’ understanding of the importance of self deception in the service of deception to an understanding of the role of repression in human social relations.