“Why Headlines Matter.” “Misleading Headlines Can Lead You Astray.” “How What You Read Affects What You See.” “How Bad Headlines Make Bad Memories.” “Eleven Reasons Headlines Are Important.” “You’ll Never Believe How Important an Accurate Headline Is.”

Those are all possible titles for this piece that I discussed with my editor. And, actually, the one that we picked may be the most important part of this article. By now, everyone knows that a headline determines how many people will read a piece, particularly in this era of social media. But, more interesting, a headline changes the way people read an article and the way they remember it. The headline frames the rest of the experience. A headline can tell you what kind of article you’re about to read—news, opinion, research, LOLcats—and it sets the tone for what follows.

Psychologists have long known that first impressions really do matter—what we see, hear, feel, or experience in our first encounter with something colors how we process the rest of it. Articles are no exception. And just as people can manage the impression that they make through their choice of attire, so, too, can the crafting of the headline subtly shift the perception of the text that follows. By drawing attention to certain details or facts, a headline can affect what existing knowledge is activated in your head. By its choice of phrasing, a headline can influence your mindset as you read so that you later recall details that coincide with what you were expecting. For instance, the headline of this article I wrote—”A Gene That Makes You Need Less Sleep?”—is not inaccurate in any way. But it does likely prompt a focus on one specific part of the piece. If I had instead called it “Why We Need Eight Hours of Sleep,” people would remember it differently.

As a result of these shifts in perception, problems arise when a headline is ever so slightly misleading. “Air pollution now leading cause of lung cancer,” ran a headline last year in the U.K. paper Daily Express. The article, however, said no such thing, or, rather, not exactly. Instead, it reported that pollution was a leading “environmental” cause; other causes, like smoking, are still the main culprits. It is easy to understand a decision to run that sort of opening. Caveats don’t fit in single columns, and, once people are intrigued enough to read the story, they’ll get to the nuances just the same. But, as it turns out, reading the piece may not be enough to correct the headline’s misdirection.

It’s these sorts of misleading maneuvers that Ullrich Ecker, a psychologist and cognitive neuroscientist at the University of Western Australia, was pondering when he decided to test how slight—and slightly misleading—shifts in headlines can affect reading. In Ecker’s prior work, he had looked at explicit misinformation: when information that’s biased influences you, no matter what you’re subsequently told. This time around, he wanted to see how nuance and slight misdirection would work.

In a series of studies, out this month in the Journal of Experimental Psychology: Applied, Ecker had people in Australia read either factual or opinion pieces, where the only shifting variable was the headline. (He had his subjects read a total of four articles—two factual, two opinion.) One factual article, for instance, talked about a change in burglary rates over the last year—a rise of 0.2 per cent—that ran counter to a ten-per-cent decline over the past decade. The slight rise, the article pointed out, was an anomalous side note; the longer trend was what was important. The accompanying headline highlighted either the smaller or the larger of the two trends: “Number of burglaries going up” and “Downward trend in burglary rate,” respectively. The opinion pieces pitted the thoughts of an expert against those of a layperson—for instance, one piece contrasted a citizen’s concerns about the safety of genetically modified food with the opinion of a scientist from the fictional company Organic Food Science Australia. The headline focussed on one of the two sides. In this case, it read either “GM foods may pose long-term health risks” or “GM foods are safe.” Each participant read all four articles.

Ecker’s goal was to test whether the degree of the slant would matter. With the factual piece, the misdirection was obvious—the entire piece was about a broader trend, with one tiny deviation. In the opinion piece, it was much more subtle. The article was, first of all, opinion, and each voice was given its own space; it was up to the reader to judge how the opinions should be considered.

After reading each article, the University of Western Australia students rated it on five different scales, to gauge things like interest and ease of reading. Once a student had read the complete set of pieces, she was given a surprise six-question quiz, with questions concerning both recollection and inference.

The headline, it turns out, had done more than simply reframe the article. In the case of the factual articles, a misleading headline hurt a reader’s ability to recall the article’s details. That is, the parts that were in line with the headline, such as a declining burglary rate, were easier to remember than the opposing, non-headlined trend. Inferences, however, remained sound: the misdirection was blatant enough that readers were aware of it and proceeded to correct their impressions accordingly. According to the study, “No matter which headline they saw, they predicted that, next year, the crime rate would go down.”

In the case of opinion articles, however, a misleading headline, like the one suggesting that genetically modified foods are dangerous, impaired a reader’s ability to make accurate inferences. For instance, when asked to predict the future public-health costs of genetically modified foods, people who had read the misleading headline predicted a far greater cost than the evidence had warranted.

Ecker and his colleagues then replicated the results in a second study—this time, the discrepancies were between the headline and the image, rather than between the headline and the text. Each headline would, or would not, match a photograph of a face that was prominently featured in the piece: it either mentioned the name of the person in the photo or of someone else. The pieces, sixteen in total, all dealt with a crime, and described one “good” person (the victim or a police officer or the prosecutor) and one “bad” (the culprit). The headline, in turn, mentioned either one or the other, for instance, “Man charged over Thornlie murder” versus “Grandfather killed in Thornlie.” The photo would then be of either the murderer or the victim.

After the students read the articles, they were asked to rate the faces that they had seen based on attractiveness, trustworthiness, dominance, and aggression—ratings that are often influenced by initial perceptions of personality. Then, after seeing the faces a third time, the students had to simply rate them as “good” or “bad.”

Here, too, Ecker found that initial impressions both mattered and were not easily corrected. When the photo matched the headline, the criminal received more negative ratings, and the victim more positive ones. If, however, the headline diverged from the photo, the victim was rated more negatively when the headline had been about the criminal, and the criminal was rated more positively when the headline had been about the victim. Initial expectations of who would be pictured affected subsequent ratings—even though, theoretically, the misperception had been corrected twice, in the text itself and in the caption.