How celebrity endorsements influence what we buy

We’ve all seen it. The high-gloss ad with a superstar front and center. Cindy Crawford sipping a Pepsi like it’s a lifestyle. Shaq swearing by a pain patch. Daniel Craig, untouchable in a white tank top, dancing his way into Belvedere’s brand story. You’d think we’d be immune by now. But celebrity endorsements still work—and not just because people are shallow or star-struck. There’s actual psychology and neuroscience behind why it lands. It has less to do with fame and more to do with how our brains evolved to follow high-status cues.

But if you’re a founder reading this, here’s the part that matters: this strategy isn’t as plug-and-play as it looks. The logic behind celebrity ads is solid, but the execution is often where younger brands mess it up. They mimic the surface—hire a known face, slap on a logo—and expect magic. This is a breakdown of what’s really going on under the hood. Because not understanding the mechanics of celebrity psychology isn’t just a creative risk—it’s a strategy tax most startups can’t afford to pay.

Let’s start with what these ads are trying to buy: trust. When a brand hires a celebrity, it’s borrowing their status, reach, and authority. It’s outsourcing the heavy lifting of credibility. Instead of proving your product is worth trusting, you signal that someone who’s already trusted—or admired—uses it. In theory, that should shortcut the decision for the customer.

But here’s the tension: the person people trust is also the one distracting them from your product. That’s the paradox. The face builds confidence, but it also pulls attention away from the actual thing you’re trying to sell.

This has been known in marketing circles for years. It’s even got a name: the “vampire effect.” A celebrity can steal the spotlight so completely that your product fades into the background. So how do these ads still work? That’s where the neuroscience comes in.

A recent study from the Wharton Neuroscience Initiative answered this exact question. Researchers tracked participants’ eye movements and pupil dilation while they viewed mock ads. The goal? Understand how celebrity status and gaze direction affect what people look at—and what they end up choosing. Two key findings stood out.

First, participants were more likely to pick a product if it was endorsed by a celebrity, and they made the decision faster. They had lower pupil dilation, which means less cognitive effort. In other words, the celebrity didn’t just grab attention—they made people feel more confident about choosing.

Second, non-celebrities were actually better at gaze-cueing. If a regular-looking person in the ad looked at the snack, viewers followed their eyes and looked at the product. When a celebrity was used, people stared at their face instead—regardless of where they were looking.

That sounds like a contradiction. But it’s not. What it shows is that we trust celebrities not because they look at the product—but because we trust them. That alone lowers the emotional effort of making a decision. It makes us feel like we’re making a good choice, even if we barely look at the thing itself.

That’s not marketing fluff. That’s biology. Primates—even in the wild—copy the behavior of higher-status individuals. We assume if the leader does it, it must be safe, good, or smart. We don’t need more evidence. That’s what brands are buying when they hire a celebrity: an evolutionary shortcut. But here’s the founder mistake—

Too many early-stage brands misunderstand what a celebrity endorsement is really doing. They think it’s about visibility. That if enough people see the face, they’ll see the product.

But that’s not how attention works anymore. If anything, what the Wharton study confirms is that celebrity overshadows the product. It only works if the category is one where buyers feel uncertain, ambivalent, or open to persuasion. Think snacks, drinks, supplements, beauty—impulse or low-consideration decisions. Not high-commitment purchases.

If you’re selling an API, a payment stack, or a values-driven DTC brand, throwing a celebrity into the mix doesn’t make your product clearer. It just muddies the water. It creates a gap between what your brand needs (clarity, consistency, education) and what the audience is receiving (glamour, persona, noise). The real risk? You spend more time managing the endorsement than building your actual brand assets. One misstep from your endorser—whether that’s a scandal, a tweet, or a campaign mismatch—and the trust you borrowed collapses. Startups don’t have the recovery budget for that.

Here’s the hardest truth I had to learn as a founder: people don’t buy just because they see. They buy because they feel ready.

Celebrity ads work because they make consumers feel more certain, not necessarily more informed. They help people justify a decision they were already considering, not push them into one they were resisting. So if your product has a long sales cycle, a steep learning curve, or a high cost—celebrity isn’t the lever to pull. It’s not going to educate or onboard. It’s not going to reduce churn or increase LTV.

What it can do is build initial confidence for products that live in an emotionally flexible zone—where people don’t hate or love the product category yet. Where they’re open to being nudged. That’s why this works for snacks. Or soft drinks. Or makeup. Or sneakers. It’s not about the depth of belief. It’s about the speed of trust.

Here’s where the story gets more interesting—and more relevant to early-stage brands.

The same study also found that participants rated the non-celebrities in the ads as slightly more attractive than the actual celebrities. And that non-celebrities generated stronger gaze-cueing. People followed their eye direction more and lingered longer on the product. There’s a lesson here: good-looking, “regular” people may not be famous—but they often feel more believable.

That’s what Gen Z marketers have already figured out. That’s why we’re seeing a rise in influencer marketing with creators who don’t have huge followings—but have earned trust inside a niche. Beauty TikTok. Fitness YouTube. Parenting Instagram. These creators don’t carry the vampire effect. They don’t overpower the product. They integrate with it.

And trust builds not just from status—but from repetition, intimacy, and consistency. That’s where younger consumers are anchoring now. Not on celebrity, but on patterned credibility. Less billboard, more bathroom shelf. So if you’re early-stage and tempted to chase a name, ask yourself this: Are you borrowing authority—or building it? Because borrowed trust is expensive. And it expires.

If I could go back to the stage where I was hiring ambassadors, here’s what I’d do instead:

1. Start with customer doubt. Map where in the funnel people hesitate. If it’s upfront trust—then yes, a credible face might help. But if it’s post-trial confusion, you need education, not endorsement.
2. Choose influence, not fame. Find someone who already lives inside your product world. Not a crossover name. Not a flex. Someone whose audience would nod and say, “Yeah, that makes sense.”
3. Design the asset around the product, not the face. The celebrity isn’t the story. The product is. Use the celebrity to transfer confidence, not content.
4. Time it to velocity. Only bring in an endorsement once you have velocity signals. When the product is working and you’re ready to widen the funnel—not distract from it.
5. Contract for collapse. Always assume something will break—scheduling, image rights, press. Write your contract like you’re protecting your runway. Because you are.

Celebrity endorsement works—but not because we love stars. It works because we hate uncertainty. The moment someone famous shows up on screen, we stop overthinking. We assume the decision is safe. That confidence shortcut is ancient—and powerful. But it only works in specific conditions.

If your product doesn’t live in that kind of category, you’re buying the wrong kind of influence. You don’t need a face. You need a system. You don’t need fame. You need frictionless proof. And most of all, you don’t need a campaign that “looks big.” You need one that feels honest. Because when people trust your product, they don’t care who’s holding it.

They care what it does for them.