Ads are designed to influence our buying habits. A good deal of money and research go into making us want to run out and buy whatever it is the ads are promoting — whether it's a hamburger, a watch or a car.

Targeted online ads. take this phenomenon to a whole new level: the exact toy (or coat, or pan) you searched for suddenly turns up as an ad on the next five websites you visit and your Facebook page. This kind of eerie ad stalking is known as targeted advertising, and its powers of persuasion can be as potent as its ability to track our every online move.

This kind of eerie ad stalking is known as targeted advertising, and its powers of persuasion can be as potent as its ability to track our every online move.

In fact, a new study finds that when people are subjected to certain types of online ads, they often actually come to see themselves the way the ads wants them to. “The power of a behaviorally targeted ad for a green product [for example] isn't just that it persuades you to buy the advertised product. It actually makes you feel more environmentally conscious and can change your behavior,” said researcher, Rebecca Walker Reczek, in a statement. “In a sense, you become more like what the ads say you are.”

To test this phenomenon, Ohio State University researchers had college students look at ads that were (so they were told) chosen based on the participants’ earlier browsing history, their demographics or neither. The ads were for a fictitious restaurant called Eatery 21, which boasted “Refreshingly Sophisticated American Classics.” Then the students were offered a (fake) Groupon coupon for the restaurant and asked how likely they’d be to buy it.

Those who’d been told that the ads were a product of their browsing history were more likely to say they’d purchase the Groupon than those who’d been told it was based on demographics or nothing at all. And this suggests that simply knowing that an ad is targeted to us may have an effect on our buying behaviors.

“When you know that you have been targeted by a specific ad, you realize that the ad carries information about you — and that can change how you view yourself,” said lead author Christopher Summers. “In this case, receiving a behaviorally targeted ad from a restaurant suggesting that you are a ‘sophisticated’ food consumer makes you think, ‘I may be more sophisticated than I thought.’ That in turn makes you more likely to buy a Groupon for the restaurant.”

This seems to be because we take on the characteristics of the ad, or the adjective that it’s promoting — in this case sophistication. “The reason this works,” Reczek explained, “is because it is changing your self-perceptions first. 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.”

Of course these targeted ads only work if the qualities the ads emphasize actually appeal to the consumer. For instance, outdoorsy ads didn’t have any effect on people’s purchasing decisions if the people weren’t the least outdoorsy to start with.

The study also points to a larger phenomenon — that our perceptions of ourselves aren’t set in stone, but can be manipulated by what’s around us.

“We like to think we are quite certain of who we are, but this study suggests that's not quite the case,” said author Robert W. Smith. “We are actually open to suggestions that can change, for example, how ‘outdoorsy’ or ‘sophisticated’ we feel we are. Our views of ourselves can be nudged one way or the other by something as simple as an online ad.”

This sort of susceptibility can make us targets for certain movies, video games and perhaps even the people we seek to surround ourselves with.

The study is published in the Journal of Consumer Research.