Advertising Isn't Just Persuasion. Here Is What It Actually Does to Markets.

In 1972, economists documented something that should have been obvious but wasn't: in states where optometrists were legally banned from advertising their prices, eyeglass prices ran significantly higher than in states where advertising was permitted.¹ No one had manipulated the consumer into paying more. The ban itself had done it, quietly, by making comparison shopping expensive and difficult. The sellers who lobbied hardest for those advertising bans were not doing the public a favor. They were protecting their margins.

That finding sits at the center of an economic debate most people never hear, because the popular version of advertising is much simpler: it manipulates you into wanting things you don't need, adds cost that gets passed to the buyer, and shifts market share around without creating anything real. Parts of that story are true. The eyeglass example is also true, and it points in exactly the opposite direction. Both can coexist because advertising is not one thing.

Why the skeptical view has a real foundation

The cynical read of advertising is credible because the most visible advertising is the most content-free. A perfume campaign built entirely on mood, a soda commercial that shows happy people without mentioning a price, a luxury brand selling an image with nothing checkable in the frame: these dominate prime-time attention and look indistinguishable from manipulation. And they add cost without obviously adding value, so the suspicion that you are paying for the ad in the price of the product is not unreasonable.

There is also a genuine economic critique underneath that gut reaction. Some advertising is what economists call combative: two competitors spending heavily primarily to cancel each other out, an arms race that raises both firms' costs without informing anyone. Where that dynamic holds, the persuasion-and-waste story has a real point.

The sums involved are not trivial. Advertising and related services constitute a distinct sector of the U.S. economy large enough to warrant its own industry category in federal data, with well over $300 billion in annual revenues tracked through national income accounts.² When that much money rides on persuasion, suspicion of waste is reasonable. The mistake is treating the most visible, most wasteful slice as though it were the whole.

The part the cynical story leaves out

Let's start with the problem the persuasion story ignores: buyers do not automatically know what exists. As economist George Bittlingmayer explains in the Concise Encyclopedia of Economics, a large share of advertising is informative: it tells consumers that a product exists, what it does, what it costs, and where to buy it.¹ That information is not a frill. Without it, a buyer has to spend real time and effort discovering options, and a better or cheaper product has no route to the customers who would prefer it.

This is why the informational view turns the "advertising raises prices" claim partly on its head. By lowering buyers' search costs and making comparison easy, advertising can intensify price competition and push prices down. The eyeglass evidence is the classic demonstration: prices were measurably higher where advertising was banned, because the ban shielded sellers from scrutiny.¹ Information is the enemy of a comfortable, uncompetitive seller, which is precisely why some sellers historically lobbied to restrict it.

Now shift to a deeper layer: even advertising that carries almost no hard facts can convey real information through signaling. A firm that spends lavishly to launch a product is posting a kind of bond. Heavy advertising only pays off if customers come back and buy again, and they will only come back if the product is actually good. So the very act of spending big signals that the firm itself expects the product to satisfy, a confidence that would be irrational to broadcast for a product destined to disappoint.¹ This connects directly to the economics of brand names: a recognized brand functions as a standing promise of consistent quality, letting buyers trust what they cannot verify before purchase.³ The content-free perfume ad still carries a message, something like "we are betting a fortune that you will love this enough to buy it again."

Why the signal is credible, not just cheap talk

A signal only works if it cannot be cheaply faked. This is where a piece most people overlook does the heavy lifting: advertising in the United States is legally constrained to be truthful. The Federal Trade Commission (FTC) requires that advertising be truthful, non-deceptive, and that objective claims be substantiated by evidence before they are made.⁴ A company cannot lawfully claim its product lasts twice as long or relieves a condition without backing it up. Deceptive claims draw enforcement action.

That regulatory floor is what makes the informational and signaling roles credible rather than empty. It creates the stakes that give a signal its meaning. The same logic now extends to modern formats: the FTC requires that paid endorsements and influencer posts be clearly disclosed, precisely so that a recommendation carries genuine information about whether it is independent or purchased.⁵ Strip away the requirement that claims must be true, and the persuasion story would be right: advertising would be cheap talk. Hold firms to truthful, substantiated claims, and a large share of advertising becomes a mechanism for moving real information from sellers who have it to buyers who need it.

For smaller businesses navigating this landscape, the FTC's guidance makes the standards concrete: claims must be truthful, fair, and backed by evidence before they run.⁶ The same rules that protect consumers also protect the credibility of advertising as an information channel.

How to read an ad the way an economist would

The better mental model is not "advertising is manipulation" or "advertising is information" but rather: advertising is a mix, and you can usually tell which is which.

When you see an ad, ask what it is actually doing. Is it telling you something checkable, a price, a feature, an availability, a comparison? That is the informative kind, and it is doing you a service by lowering what it would otherwise cost you to find that out yourself. Is it pure mood and image with nothing to verify? Read it as a signal: the firm is spending to tell you it stands behind the product, but supply the missing facts yourself before buying. And when two rivals are simply shouting over each other in a mature market where everyone already knows the products exist, recognize the combative case for what it is and discount accordingly.

Overall, the evidence points somewhere the popular story misses. Advertising is neither the villain of the manipulation narrative nor a harmless public service. It does real informational work: reducing search costs, signaling quality, sharpening competition, alongside its persuasive and occasionally wasteful uses. The economy spends enormous sums on it not because buyers are dupes but because, in a world of differentiated products and imperfect information, telling people what exists and standing behind it is genuinely valuable. The next time you are tempted to wave an ad away as mere persuasion, ask what information it is carrying. Often there is more there than the cynical story admits.