In 1885, a German psychologist named Hermann Ebbinghaus published one of the strangest research programs in the history of psychology. He had spent two years sitting alone in his office memorizing thousands of nonsense syllables (WID, ZOF, CAL) and recording how quickly he forgot them.
Ebbinghaus produced what is now called the Forgetting Curve — a graph showing that memory decays exponentially after initial learning. He found that without reinforcement, humans forget roughly 50% of newly learned information within an hour, 70% within a day, and 90% within a month.
If you've ever wondered why Coca-Cola — one of the most recognized brands in human history — still spends over $4 billion a year on advertising, the answer is in Ebbinghaus's curve.
Brand memory decays. And brand memory that's allowed to decay is, in commercial terms, brand revenue that disappears.
What Coca-Cola Is Actually Buying With $4 Billion
The argument that's most useful for understanding Coca-Cola's marketing budget comes from Byron Sharp at the Ehrenberg-Bass Institute in South Australia. His 2010 book How Brands Grow — which has become required reading inside most large consumer-marketing organizations — makes a claim that's still controversial in advertising circles but increasingly empirically supported.
Sharp's claim is that brands grow primarily by being mentally available and physically available, not by being differentiated. Mental availability means the brand comes to mind in the moments when a purchase decision is being made. Physical availability means the brand is actually on the shelf or in the channel when the buyer is ready.
Most marketing dollars, Sharp argues, are better spent maintaining mental availability than chasing brand differentiation, because mental availability is the variable that actually predicts purchase behavior at scale.
Coca-Cola is the cleanest empirical demonstration of Sharp's argument that exists in modern marketing. The brand doesn't really need to introduce itself to anyone. Roughly 94% of the world's population recognizes Coca-Cola's logo. The advertising isn't about acquisition. It's about non-decay.
Each $4 billion ad spend is an annual reinvestment in mental availability — buying enough exposure to push back against Ebbinghaus's curve and keep the brand mentally accessible in the seven or eight buying moments a typical consumer encounters in a given week.
The Spacing Effect
Ebbinghaus also discovered something called the Spacing Effect, which turns out to matter more for marketers than the Forgetting Curve itself.
The Spacing Effect says that information is retained better when exposures are distributed over time rather than concentrated in a single burst. Three exposures spread across three weeks produces stronger memory than three exposures in three minutes. The mechanism — re-formalized in modern cognitive neuroscience as "consolidation through repeated retrieval" — is one of the most robust findings in memory research.
Coca-Cola's media buying strategy is essentially an industrialization of the Spacing Effect. The "Holidays Are Coming" Christmas advertising — the red truck, the carolers, the chorus — has run, with small variations, in roughly the same window every December since 1995. The annual return of the ad is itself the mechanism. You don't watch the truck once and remember it forever. You watch it every December for thirty years and the association between Coca-Cola and the warm-feeling-of-the-season hardens into something that no competitor can dislodge.
This is why Mark Ritson, the marketing professor and consultant, keeps writing that most brands underinvest in long-term advertising and over-invest in short-term performance marketing. Les Binet and Peter Field's research, summarized in The Long and the Short of It, suggests that the optimal split is roughly 60% long-term brand building, 40% short-term activation. Most modern marketing teams are running closer to 30/70, and Binet/Field argue that the imbalance is silently eroding long-term brand equity.
Coca-Cola's $4B has been running closer to 60/40 for decades. Their brand has not eroded.
Distinctive Brand Assets
The other Ehrenberg-Bass concept worth understanding is Distinctive Brand Assets — the visual, audio, and verbal cues that uniquely identify a brand without requiring the brand's name to be spoken.
For Coca-Cola, these include the hourglass bottle (patented in 1915, designed to be recognizable in the dark or even when shattered), the Spencerian-script logo (essentially unchanged since 1887), the color red, the Polar Bear character (introduced 1922), the white wave on the can, the "Coca-Cola" jingle. Jenni Romaniuk's book Building Distinctive Brand Assets is the definitive operator's manual on the concept.
Each of these assets has been maintained, with almost religious discipline, for decades. A new Coca-Cola creative director cannot just decide to change the logo. They cannot decide to drop the polar bears. The brand's DBAs are treated as infrastructure, not creative variables.
This is the discipline most brands lack. Marketing teams, especially in challenger brands, get bored of their own assets long before the customer does. They redesign the logo. They drop the mascot. They modernize the jingle. Each redesign resets the Forgetting Curve and re-imposes the cognitive cost on the customer of relearning who you are.
Coca-Cola, almost uniquely, refuses to do this. Which is why, against any sane measure of brand recognition, they are the closest thing the consumer economy has to a permanent fixture.
What I Take From All This
The thing I find most interesting about Coca-Cola isn't the brand. It's the philosophy of memory the company operationalized before behavioral economics had names for any of it.
Coca-Cola is, in effect, paying $4 billion a year to keep its brand on the right side of Ebbinghaus's curve. Most of that spending looks, to outsiders, like waste. Why advertise a product everyone already knows about? The answer is that what everyone already knows will, without reinforcement, become what nobody can quite remember in the moment of purchase — and that's the moment that determines whether the brand grows.
If you're managing any brand whose customers buy intermittently — once a week, once a month, once a year — Ebbinghaus's curve is operating on you. Your customer's memory of your brand is decaying right now, by default, unless you're spending to slow the decay.
The question isn't whether to spend on brand. It's whether you're willing to look at a graph from 1885 and adjust your marketing budget accordingly.
Coca-Cola did. Almost nobody else has.