74% of digital natives—consumers between 16 and 35 years old—say they don’t want brands targeting them in their feeds on Facebook and other social networks, finds a new Harris Poll survey commissioned by Lithium Technologies. That’s 10 percentage points higher than the response of the broader U.S. online population.

Moreover, 56% of digital natives and 48% of the all U.S. online consumers say they have cut back or stopped used social networks entirely because of the presence of targeted ads in their feeds.

Those results fly in the face of the business models of nearly every major social network, including Facebook Inc. The world’s largest social network continues to generate double-digit advertising revenue growth in large part because it enables companies to finely target their ads at consumers. In the first quarter, for example, Facebook generated $11.86 in average advertising revenue per user in the United States and Canada, up 55.6% from $7.62 a year ago.

“Those business models have been about placing ads,” says Katy Keim, Lithium’s chief marketing officer. “They haven’t been about the effectiveness of the ads.”

She argues that although Facebook and other social networks have successfully driven brands to pay for ads to ensure their messages are seen, that doesn’t mean  those ads are producing strong results—particularly from younger consumers.

Whether that claim is accurate is not clear. The report finds that 95.8% of marketers say Facebook, which many say offers the most finely targeted targeting among social networks, presents the best return on investment among social networks, according to a March survey from digital marketing firm Social Fresh.

Keim suggests Lithium’s survey means brands have to adjust the way they market to younger consumers.
“Brands have to build trust with a younger audience,” she says.

The survey finds that 50% of digital natives trust blogs, compared to 30% of consumers older than 35. Younger consumers also are more likely to trust online communities (61% compared to 45% of older consumers) and celebrity endorsements (35% compared to 19% of older consumers).

“Celebrity is such a wide-ranging concept now,” Keim says. “Tyler Oakley is a YouTube creator and also a celebrity. The Kardashians are celebrities. Mommy bloggers are celebrities. When these people endorse products, people listen.”

Retailers should also think more deeply about their marketing efforts, she says. It isn’t enough to buy an ad, they also have to think about engaging consumers in a conversation, whether that’s a dialogue sparked by Oakley or a brand’s post.

“I’m completely convinced those brands with the mentality and mindset to engage with consumers will win,” Keim says. “Those that don’t will be in real trouble.”