Every Marketing Problem You Solved by Adding Something Made the Next One Worse

Your Google Ads aren't converting well enough. So you build three more campaigns. Your social media isn't getting engagement. So you add TikTok. Your leads are soft. So you buy another tool to score them.

Every time your marketing disappoints, you add something. A new campaign. A new channel. A new piece of software. A new agency. A new strategy layered on top of the old strategy that's still running underneath.

Here's the thing nobody tells you: that instinct to add is a documented cognitive bias. And it's making your marketing measurably worse.

Your Brain Literally Doesn't Know How to Subtract

In 2021, researchers at the University of Virginia published a study in Nature that changed how psychologists think about problem-solving. Across eight experiments with 1,585 participants, Adams, Converse, Hales, and Klotz found that people systematically default to adding elements when trying to improve something, even when removing elements would be simpler and more effective.

In one experiment, participants were asked to make a grid pattern symmetrical. They could add shaded squares or remove them. Out of 94 people, 73 added squares. Only 18 subtracted. The subtractive solution was objectively simpler. Most people never even considered it.

The researchers found something even more concerning: the higher your cognitive load, the stronger the bias. When people are stressed, overwhelmed, or juggling multiple priorities, they become even more likely to default to adding.

Sound like any business owner you know?

You're running a company. You're managing staff, chasing invoices, answering emails, and somewhere in between, you're supposed to figure out why last month's leads dropped 20%. Your brain, under load, reaches for the only solution it can generate quickly: add something.

What Addition Bias Actually Looks Like in Marketing

This bias doesn't show up as one bad decision. It shows up as dozens of small, reasonable-sounding decisions that compound into a mess.

The Algorithms Want You to Consolidate

Here's the part that makes addition bias especially costly in 2026: the platforms themselves now reward subtraction.

The same principle applies to Meta. Advantage+ campaigns work best when they have a broad audience and sufficient budget to learn. Fragment your spend across six ad sets targeting slightly different demographics and you're not being precise. You're crippling the algorithm's ability to find the people most likely to convert.

This isn't a philosophical argument. It's a mathematical one. An algorithm that sees 50 conversions per month in one campaign makes better predictions than one that sees 8 conversions across six campaigns. The data compounds in concentrated structures and dissipates in fragmented ones.

We wrote previously about why your marketing is a multiplication problem, not an addition one. The same logic applies here: concentrating your resources multiplies their effect. Fragmenting them divides it.

The IPA Data: Fewer, Bigger, Bolder

Les Binet and Peter Field analysed 996 campaigns from the IPA Effectiveness Awards and found a clear pattern: the most effective campaigns were fewer, bigger, and bolder.

Their research showed that total business effects rise steadily with campaign duration and investment. Short, fragmented bursts of activity produce sharp but short-lived uplifts. Sustained, concentrated campaigns produce compounding returns that grow over time.

Binet has been explicit about the implication: optimise your media mix before commissioning more creative. Most businesses do the opposite. They produce more ads, launch more campaigns, and test more variations while the fundamental structure of their marketing remains fragmented and underfunded.

The IPA research also found that advertising effectiveness has been declining over the past decade, and the primary culprits are short-termism, narrow metrics, and underinvestment. In other words, exactly the behaviour that addition bias produces: lots of small, measurable, short-term additions instead of fewer, bigger, long-term commitments.

Sam Tomlinson captured this perfectly in his 10 Marketing Commandments: "Better not to spend than spend poorly." The corollary for most SMEs is uncomfortable: you'd get better results running two campaigns well than six campaigns badly.

The $300 Million Subtraction

Rory Sutherland, Vice Chairman of Ogilvy UK, has built an entire philosophy around the idea that the most valuable business improvements are often the smallest and most counterintuitive.

His most striking example is what's known as "the $300 million button." An e-commerce site changed a single button label from "Register" to "Continue" and added one line of reassuring text. No new features. No new campaigns. No new tools. Annual revenue increased by $300 million.

The improvement came from subtraction: removing the friction of forced registration. Not adding a loyalty program, a new checkout flow, or a promotional campaign. Just taking away a single word that was scaring people off.

Sutherland's Rule 10 says it plainly: "Dare to be trivial." The smallest change in context can have immense effects on behaviour. A fly etched into a urinal at Schiphol Airport reduced spillage by 80%. The London Underground's biggest improvement in passenger satisfaction wasn't faster trains. It was dot-matrix display boards showing when trains would arrive. The wait didn't change. The uncertainty did.

For SMEs, the parallel is direct. Before you add another campaign, another channel, or another tool, ask: what happens if you remove one thing that's creating friction? What if the problem was never your ads at all?

The Subtraction Audit

If addition bias is hardwired, the only defence is a deliberate practice of subtraction. Here's a framework.

But doing nothing is sometimes the hardest and most valuable marketing skill. Subtracting is one step braver than nothing: it's actively choosing to concentrate your force.

What This Means for Your Business

Your marketing doesn't need another campaign, another channel, or another tool. It probably needs fewer of each, with more resources behind the ones that remain.

The science is clear: your brain will fight you on this. Under stress, under time pressure, facing a problem you need solved quickly, you will reach for addition every time. It's not a character flaw. It's human cognition.

The fix is equally clear. Build subtraction into your process. Audit quarterly. Ask "what can we stop?" before asking "what should we start?" Make removal a deliberate practice, not a last resort.

The businesses that figure this out don't just save money. They build something more valuable: clarity. Fewer campaigns mean more data per campaign. More data means better optimisation. Better optimisation means better results. Better results mean you don't need to add something new next month.

That's the real compounding effect in marketing. Not addition. Subtraction.

Further Reading

• People systematically overlook subtractive changes - Adams, Converse, Hales & Klotz, Nature 2021. The foundational research on addition bias across eight experiments.
• Les Binet and Peter Field: The Long and the Short of It - IPA effectiveness data from 996 campaigns showing why fewer, bigger campaigns outperform.
• Why Martech Stacks Are Consolidating in 2026 - Heinz Marketing on the industry shift from tool accumulation to simplification.
• How Campaign Structure Shapes Google Ads Performance - Search Engine Land on why simpler account structures outperform complex ones.
• Rory Sutherland on Behavioural Economics, Marketing and Human Irrationality - The case for "dare to be trivial" and why small changes beat big additions.