The 1920s

Why it mattered

This is the decade advertising stopped selling products and started selling identities. Installment credit put durable goods within reach of ordinary households, and the advertisement's task changed from explaining what a thing did to explaining what owning it said about you. Everything the trade is admired and mistrusted for begins here.

What changed

Credit changed the arithmetic. Buying on installment made cars, radios, and appliances purchasable by people who could not pay outright. Advertising no longer had to overcome the price — it had to overcome the hesitation.

Radio arrived and did not kill the magazine. Commercial broadcasting from 1922 introduced a rival medium, but its early advertising was verbal and unillustrated. The magazine kept what radio could not offer: the image, the coupon, and the page a reader could keep.

Design caught up with the century. European modernism reached American commercial art. Photography began displacing painted illustration. Advertisements acquired white space, asymmetry, and sans-serif type — the visual argument that a product belonged to the present rather than the past.

Psychology entered the copy room. Agencies hired behavioural researchers and applied laboratory language to persuasion. Whether the science was sound mattered less than the effect on practice: the trade began treating the reader as a set of exploitable responses rather than a mind to be convinced.

The techniques Manufactured dissatisfaction — establish a standard the reader has not met, then supply the remedy. The failing is created by the advertisement, not discovered by it Planned obsolescence, stylistically enforced — the annual model change, making a functioning possession socially out of date The aspirational figure — depicting not the buyer but the person the buyer wishes to be seen as Expert and celebrity endorsement — the physician, the film actress, the society hostess, paid and unattributed Photographic realism — the photograph carries an evidential authority that illustration cannot, and the trade exploited exactly that The clinical euphemism — naming an ordinary human condition in medical language so that it reads as a diagnosable problem Copy as narrative — the long-form advertisement written as a short story, with the product as resolution rather than subject The competing brand named — direct comparison, a break from the previous convention of ignoring rivals entirely What it left behind

By 1929 advertising had established that demand could be manufactured rather than met. That capability made the trade indispensable to industry and permanently suspect to everyone else — and it is the reason the decade's advertisements still read as recognisably modern in a way that anything from the 1900s does not.