When something isn’t working, almost every marketer reaches for the same fix…
Add another benefit in the copy, another platform on the plan, another format to test, another paragraph explaining the offer a different way.
Adding feels like effort, and effort feels like the answer 💡
The smarter move is usually to do the opposite. Fewer claims, fewer platforms, shorter copy. I’ve been giving my clients this advice for many years. Then recently, while listening to an episode of the Nudge podcast by Phill Agnew, I learned the name for the instinct I keep having to fight in myself and my clients.
It’s called the subtraction bias, our very human tendency to add when taking away would serve us better, and there is solid research behind it.
The Lego bridge that explains everything
The story Phill tells in his podcast starts with an engineering professor called Leidy Klotz building a Lego bridge with his three-year-old son. The two support towers were different heights, so Klotz turned around to grab an extra block for the shorter tower. By the time he turned back, his son had simply removed a block from the taller one. It was faster and used less, but it never occurred to the adult in the room.
Klotz teamed up with researchers at the University of Virginia to find out whether that instinct was universal, and they published the results in Nature in 2021. Across eight experiments, people consistently defaulted to adding when asked to improve something, and overlooked the option of removing, even when removing was quicker, cheaper or plainly better.
Our brains treat ‘improve’ and ‘add more’ as the same instruction.
The most worrying part for busy marketers is that researchers found people were even less likely to spot subtractive solutions when they were under higher cognitive load. The busier and more stressed you are, the more stuff you’ll bolt on at precisely the moment you should be stripping it back.
Every claim you add waters down the last one
The subtraction bias would matter less if adding were harmless. But it isn’t…
In 2007, researchers at the University of Chicago ran a study known as the tomato study. One group of participants read that eating tomatoes helps prevent cancer. Another group read that eating tomatoes helps prevent cancer and degenerative eye disease. When asked how effective tomatoes were at preventing cancer, the group who’d been given two benefits rated them around 12% less effective than the group given one.
So adding a true, positive, relevant second benefit made the first benefit less believable.
Psychologists call it the goal dilution effect, and it means every extra claim on your website, your sales page or your ad quietly weakens the ones already there. The brand that says “we do one thing brilliantly” will be trusted over the brand that says “we do eight things brilliantly,” even if the second brand is telling the truth. Five Guys built an empire on burgers and fries partly because a short menu signals mastery in a way a long one never can.
The same principle holds for volume of words. Harvard’s Todd Rogers and Jessica Lasky-Fink emailed 7,002 US school board members asking them to complete a survey. Half received a warm, well-written 127-word version. Half received a 49-word version with the pleasantries cut. Most people shown both emails predicted the longer, more gracious one would win. But the short email nearly doubled the response rate, at 4.8% against 2.7%.
Your readers pay for your words with their time, and they notice the price.
A client’s ad campaign
Over the summer, I ran a Meta advertising campaign for LiveWell Dorset, a service that helps people move more, eat better and feel healthier. I tested two headline messages against each other with the same imagery. One was “Live Well for a life you love” and talked about long-term health and lifestyle goals. The other was “Feel better, starting this week” and talked about changing one thing to feel a bit better right now.
On paper, the first message is the stronger promise. It’s bigger, more aspirational, the kind of line that gets an easy yes from management. The second promises far less. And, you’ve guessed it! The second won, with broader appeal across every demographic we showed it to.
The reason is simple. A promise you can imagine keeping by Friday beats a promise about your whole life, because the person seeing your ad is scrolling past on their lunch break with a hundred other things on their mind. The smaller claim asks less of their imagination and less of their trust, so it gets more of both. The client liked the winning adverts so much, they’ve carried through into LiveWell Dorset’s print advertising (which I’m obviously taking as a huge compliment).
The subtraction discipline applied to the test itself, too. When you’re testing, it’s tempting to keep adding creatives and messages to be thorough, but with a fixed budget, every variant you add splits the data thinner and dilutes what the test can teach you.
We understand niching (we just struggle to do it)
For decades, universal marketing advice has been to pick a niche, lead with one clear benefit, and make sure your ideal client can look at your content and know within seconds what it’s for and that it’s for them.
The subtraction bias explains the gap between understanding this and actually doing it. Niching is a strategy, and strategies live in documents. Subtraction bias is a human tendency: choosing to add one more service on the website, one more audience in the ad set, one more benefit in the caption.
Knowing you should focus was never the hard part. The hard part is that your brain registers every removal as a loss and every addition as progress, which is how the sharp, focused marketing you planned in January turns fuzzy by June.
So the question I now ask clients has changed from “what’s your niche?” to “what are you willing to take away?”
One more reason this matters
Yes, unfortunately I do have to mention AI at some point 🫠
AI has the same additive bias we do, because it learned from us! Ask any AI tool to improve your copy and watch it grow. Ask it for campaign ideas and count how many involve doing more.
This is why I’m relieved Phill Agnew and science finally showed up to support what I’d been saying. Doing less marketing is a strategy, and now I can explain why it works.
So before you add another thing to your marketing this month, what are you taking away? Maybe cut a claim from your homepage and see if the remaining ones land harder. Or halve the word count of your next email and watch what happens to replies. Go ahead and quit the platform you’re only on from a misguided sense of obligation, and spend the recovered hours on the one that actually gives back.
Your Lego bridge probably has a block too many. Try taking one off and see what happens.
Need help choosing what to cut?
Knowing you should do less and knowing what to subtract are two different things (and the latter is far easier with an outsider’s perspective). When you book a Power Hour with me, I’ll send you Worth The Squeeze, a handy prep sheet to assess your marketing activities. Then you get a full hour of my marketing brain on what deserves your time and budget and what goes on the stop list.
