If people have told you these habits are odd or off-putting, science suggests they’re likely wrong. Here’s why they signal the opposite, according to research.

Most of us have a fairly tidy mental image of what an “intelligent person” looks like: someone with good habits, who’s always articulate, composed and chooses their words with the utmost care. The allure of this unassuming, quiet type who has everything figured out before they speak can be quite tempting. But psychological research keeps dismantling this image.

Over the past decade, researchers studying language, cognition and verbal processing have identified several behaviors that correlate with higher cognitive ability, but that are routinely mistaken for their opposite. Two of the most compelling involve habits that many intelligent people might have been quietly apologizing for their whole lives.

Although neither will win you friends at a formal dinner, both are supported by a growing and credible body of peer-reviewed research. Here’s a breakdown of both.

There is a long-standing cultural assumption that people who talk to themselves are, at best, eccentric and, at worst, showing signs of something more concerning. It’s the kind of behavior that invites sideways glances in supermarket aisles and prompts well-meaning family members to ask if you are OK. The research, however, tells a different story.

In a 2012 study by Gary Lupyan and Daniel Swingley published in the Quarterly Journal of Experimental Psychology, participants were asked to search for a common object — let’s say, for instance, a banana — among images of other objects. Some participants were instructed to repeat the object’s name aloud as they searched. Others, conversely, remained silent.

Consistently, the researchers found that those who spoke the target name out loud found it significantly faster. Speaking, it turned out, made the visual system a more efficient detector. Lupyan and Swingley described this as the label feedback hypothesis: the idea that verbal labels don’t just describe the world, but that they actively shape how we perceive it.

When you externalize a thought into spoken language, you engage both your language production system and your auditory processing system simultaneously. The word you speak becomes a perceptual cue — one that tunes attention, sharpens focus and primes the brain for what it’s looking for.

In other words, people who use language to think appear to have a cognitive advantage on tasks that require holding information in mind. A 2023 review published in Frontiers in Psychology further mapped the range of functions served by self-talk: problem solving, self-regulation, working memory, task-switching, rehearsal and what researchers describe as the management of higher-order cognitive processes.

Self-talk, the authors concluded, is present in a significant portion of conscious experience and serves a remarkably broad set of mental functions. What this research cumulatively suggests is that talking to yourself is not a performance of thought. It is the externalization of your thoughts: they’re sharpened and made more effective by virtue of being spoken.

The habit that others read as a lack of self-control is, neurologically speaking, a form of cognitive efficiency. People who do it naturally may have discovered, without any formal instruction, one of the most reliable ways to keep their thinking on track.

The assumption here is so embedded that it has become a kind of folk wisdom: people who swear frequently do so because they lack the vocabulary to express themselves any other way. It is, in this view, portrayed as a sign of laziness: a linguistic shortcut taken by people who cannot be bothered to find the right word. But this is almost precisely backwards.

The most cited challenge to this assumption comes from a series of studies by Kristin and Timothy Jay, published in the journal Language Sciences in 2015. Participants were given a standard verbal fluency task, in which they had to name as many words beginning with a specific letter as they could in one minute. Then, they were given a taboo fluency task, in which they were asked to list as many swear words as they could in the same timeframe.

The researchers found a clear positive correlation: participants who scored highest on the verbal fluency test also generated the most swear words. Those with the weakest general vocabulary produced the fewest. This suggests that the same cognitive resource that gives someone access to a rich general lexicon also gives them access to a rich taboo lexicon. The vocabulary is simply larger on both ends.

The more interesting question is why this relationship exists at all. Jay, who has studied swearing for more than four decades, argues that taboo words occupy a specific and irreplaceable function within the lexicon. They carry emotional precision that ordinary words cannot reliably deliver.

This is because using swear words well — knowing when a precisely placed expletive lands with more force than a carefully constructed sentence — requires reading social context, understanding register and exercising nuanced linguistic judgement. These are not the skills of someone with a limited vocabulary. They are the skills of someone with a sophisticated one.

There is an important caveat here, which the research itself raises. Research published in 2018 in the Journal of Language and Social Psychology notes that people, even those who are not personally offended by profanity, still rate swearers as less intelligent and less trustworthy than non-swearers.

The perception gap is real and persistent. This means that the cognitive signal embedded in swearing is frequently overridden by social noise. What the research reveals is not that you should swear more, but that the habit itself — the fluency with taboo language, the ease of access to it — correlates with verbal intelligence in ways that the lay assumption completely inverts. Knowing when not to swear is, arguably, its own form of intelligence, too.

Both of these habits share something structurally interesting. They look, from the outside, like failures of self-regulation: the inability to keep thoughts to yourself and the inability to keep certain words out of your mouth.

However, what the research describes is something closer to the opposite: they reflect a natural inclination to use language as a cognitive tool, to deploy it with precision and fluency, to engage the full range of the lexical system rather than keeping it safely contained.

Intelligence, in practice, rarely announces itself; it tends to show up in stranger and more inconvenient ways. It can show up in the person narrating their own thoughts in the cereal aisle, or the colleague who drops one well-placed word in a meeting that changes the entire temperature of the room. The habits you have been told to suppress may be worth paying closer attention to.

Intelligence often hides in plain sight. Are you aware of how your habits shape yours? Take the science-backed Self-Awareness Outcomes Questionnaire to find out.