The era of targeted online ads is a mixture of convenient and creepy — advertising algorithms now ensure that shortly after you search for a wedding venue, for instance, banner ads for wedding DJs and florists will begin popping up on your screen. But now, a new study in the Journal of Consumer Research suggests that targeted ads may even change how you feel about yourself.

Researchers found that internet users who knew that they were seeing targeted ads for environmentally friendly or sophisticated products actually began to think of themselves as greener and classier.

"The power of a behaviorally targeted ad for a green product isn't just that it persuades you to buy the advertised product. It actually makes you feel more environmentally conscious," said Rebecca Walker Reczek, a professor of marketing at Ohio State University and co-author on the study, in a statement. "In a sense, you become more like what the ads say you are."

"Behavioral targeting" is a fancy word that advertising executives use to describe Google and Facebook acting kind of creepy. Essentially, computer algorithms notice what you're searching for online and begin to infer from that what your interests might be. Then the algorithm delivers specific advertisements, more or less tailored toward your interests. The evidence suggests that it works astonishingly well — one 2010 study found that behavioral targeting enhances click-through rates by as much as 670 percent relative to conventional online ads.

If you don't know it's happening, then you're probably just pleasantly surprised to find that the internet seems to have a striking number of ads for the exact genre of book, movie, or restaurant that you enjoy. But if you're aware of ad targeting, then you know that those ads mean something. They're the sum total of your searches — an unbiased, unabashed look at what sort of person you are online. And sometimes, that knowledge can mess with your head.

"This research introduces the notion that behaviorally targeted advertisements act as implied social labels," the authors write. "We propose that when a consumer knows that an ad has been behaviorally targeted, he or she recognizes that the marketer has made an inference about his or her identity based on his or her past online behavior."

For the study, researchers asked 188 college students to surf the internet. After about ten minutes of clicking around, the computer presented them with an ad for a fictitious restaurant called Eatery 21, advertised as "sophisticated." Some students were told that the ad had been targeted to them based on their search history, while others were told that the ad was random, or based on their age and gender. A survey afterwards revealed that those who believed the ad had been tailored to their preferences were not only more likely to show interest in the restaurant, but also more likely to say that they indeed had "sophisticated food preferences."

In a second experiment, the researchers presented the same group of students with a targeted ad for an environmentally friendly product. Here, too, they found that the students who were told they'd been targeted were more likely to say they'd donate to an environmental cause and, in a follow-up survey, were more likely to identify as "green" than other students. "If an ad makes you feel sophisticated or environmentally conscious, you are more likely to engage in all kinds of behaviors related to that trait — not just buy the advertised product," Reczek says.

There was one major caveat in both experiments — users had to at least consider the targeted ad plausible. To demonstrate this point, researchers conducted a third experiment and found that faux targeted ads for outdoors products left no impression on consumers who had previously reported they had little interest in outdoor activities.

In any case, the findings suggest that when people know they are seeing targeted ads, they begin to identify with the product and are actually more likely to buy. But the study also suggests something deeper and, perhaps, more unsettling. Our self perceptions may be so fragile that something as insignificant as an online ad can actually change how we view ourselves. "We like to think we are quite certain of who we are, but this study suggests that's not quite the case," said Robert Smith, a marketing professor at Ohio State and co-author on the study, in a statement.

"Our views of ourselves can be nudged one way or the other by something as simple as an online ad."

This article originally appeared at Here's how online ads are screwing with your brain