U.S. President Donald Trump gestures during a breakfast with Republican Senators at the White House in Washington, D.C., U.S. November 5, 2025. REUTERS Kevin Lamarque
PsyPost reports that casual disregard for reality poses a "uniquely potent threat" to public knowledge and belief.
People are more likely to believe false information when it comes from someone who ignores the truth altogether rather than a liar “who actively tries to deceive.” This is because repeating statements made by someone who is completely indifferent to facts “heavily increases how truthful those statements feel” to an audience.
Additionally, casual Trump-style disregard for reality appears to pose a deadly threat to community knowledge. According to researchers, the divide sits between a simple “liar,” — someone who knows the truth and intentionally tries to mislead an audience — and a “bulls——er,” who “communicates with little to no regard for the truth, evidence, or established facts.”
A statement made by a “bulls——er” might happen to be true, or it might be false, but the defining characteristic is the speaker’s absolute indifference to reality. Because they do not actively try to hide a specific truth, people often judge them less harshly than they judge outright liars.
In a 2023 study, Wake Forest University psychology professor and author John V. Petrocelli explored how untrustworthy sources influence consumer attitudes over time. Participants read an advertisement for a fictitious gluten-free pizza and then learned the advertiser was either a simple “liar” or “a known bulls——er.” Astoundingly, after a two-week delay, participants who had been “warned about the bulls——er” actually reported more positive attitudes toward the pizza than those warned about the liar. This, said Petrocelli, demonstrated a “sleeper effect,” where the deceptive influence of the “bulls——er” actually grew stronger over time. The researchers also found that people possess a higher “dismissal readiness” for lies, meaning they find it easier to entirely reject a known lie than a statement from the consummate liar.
“But the harder question … raised, and one almost nobody had tested empirically, was whether “bulls—— actually does more damage to what people believe, precisely because it doesn’t trigger the same skepticism a known lie does,” said Petrocelli.
The “illusory truth effect” is a psychological phenomenon where people tend to believe nonsense as true after hearing it multiple times. When the human brain encounters a repeated statement, it processes that information more easily, and people often mistake this mental ease for actual truth.
But Petrocelli wanted to see if knowing the source of a claim changes this effect. “If a person knows a statement comes from a bulls——er rather than a liar, they might not filter the repeated information as strictly,” he said.
Study participants were given 42 different statements. Half of them factual and half completely false. And it turned out that even after study participants were told whether the source of the info was a liar or a “bulls——er,” the exact same statements made by the “bulls——er,” was trusted significantly more than the liar. And in two other tests the repetition of the bulls—— claims successfully tricked their minds into believing the statements.
“A known liar’s claims get flagged and rejected; a bulls——er’s claims, because they’re not certainly false, slide by with much less resistance, and repetition alone makes them feel truer over time,” Petrocelli said.
“If anything, the practical takeaway is: don’t just ask ‘is this person lying to me,’ ask ‘does this person actually know or care whether this is true,’” said Petrocelli.