Nudges have been the darling of behavioral science—subtle tactics designed to steer choices in predictable ways. Businesses use them everywhere, from pricing strategies to product placement.

So, can fundraisers just borrow these tricks and expect the same results? Not quite.

The gap between consumer and donor decision-making is massive. Buying a product is about value-for-money and deals. Giving is about identity, personal values, and emotional connection. That’s why market-tested insights don’t always translate neatly into charitable giving.

But beyond that, there’s another challenge: not all donors react the same way to the same nudge. Many effects we see in experiments are “lost” in real-world application due to heterogeneous responses—different donors behaving in different ways based on underlying psychological differences.

If fundraisers only focus on which test wins, they miss a deeper opportunity: understanding why an effect happens, for whom, and under what conditions. That’s where better testing design comes in. Let’s look at two classic nudges that don’t behave as expected in a fundraising context—and how charities should rethink their approach to testing.

The Middle-Option Bias: Does It Really Work for Donations?

Marketers know this trick well—offer three pricing options, and consumers will gravitate toward the middle. That’s why your local coffee shop has Tall, Grande, and Venti, and why streaming services offer Basic, Standard, and Premium.

Seems like a great way to nudge donors toward higher giving levels, right? Not so fast.

A UK nonprofit wanted to encourage monthly donors to upgrade their gifts. The original appeal presented two choices:

• Keep donating £21/month
• Increase to £26/month

We suggested adding a third option: a £30/month upgrade, predicting that more people would choose £26 as a “compromise.”

But that’s market logic—not fundraising logic.

What Actually Happened?

Instead of more donors picking £26, fewer did (34% vs. 39% in the control). However, that missing 5% didn’t disappear—they simply went for the higher amount (£30). So, while the upgrade rate stayed the same (39% across both groups), revenue increased in the test group.

Why Market Logic Failed Here

In consumer settings, the middle option feels like the best deal—a bigger coffee, better phone plan, or extra perks. It’s a win-win: businesses boost profits, and customers feel they’re getting more for their money.

But giving doesn’t work that way. Donors don’t get more “warm glow” by giving slightly more. Their choice is shaped by personal capacity and emotional connection, not a subconscious need to compromise. Instead of using a middle option to drive upgrades, fundraisers might benefit more from simply offering a higher ceiling—because some donors will give at the top level when asked.

Heterogeneity: Why a Simple “Winner” Isn’t Always the Full Story

A critical takeaway from this test is that the effect wasn’t uniform across all donors. Some ignored the middle option, while others jumped to the highest. This raises a crucial point: many experimental effects fail to replicate at scale because of heterogeneity in donor psychology—different people respond differently based on underlying values, beliefs, and motivations.

A standard A/B test tells us which version worked on average, but it doesn’t tell us why it worked—or for whom. To design better tests, charities need to go beyond simple “which version won?” approaches and start segmenting results based on donor characteristics. This might mean linking test results to survey data or donor profiles to uncover patterns in psychological traits that influence donation choices.

Gain vs. Loss Framing: When Fear Backfires

Loss aversion is one of the strongest biases in human psychology—we hate losing more than we enjoy gaining. That’s why businesses use “last chance” deals and fear-based messaging (“Don’t miss out!”).

At first glance, this seems like a no-brainer for fundraising. Highlight what’s at stake—“Without your gift, children will suffer”—and urgency should drive action.

Except, it often backfires.

The Research Says…

A study found that loss-framed fundraising messages (“Without your help, children will die”) performed worse than gain-framed ones (“Your gift will save lives”).

Worse, loss framing triggered psychological reactance—a resistance to the ask. When donors feel pressured or guilted into giving, they may reject the appeal entirely.

Why Market Logic Fails Here

Loss-based marketing works for sales because people fear missing out on a deal. But in fundraising, a loss frame doesn’t make donors worry about losing something for themselves—it makes them feel personally responsible for a tragedy. That’s an entirely different emotional response.

People don’t like being forced into a moral corner. It threatens their autonomy, which self-determination theory tells us is critical for motivation. Instead, hope-based appeals—showing donors how they can create positive change—often inspire more giving, both immediately and in the long run.

Fundraising Needs More Than Just “Winning” Tests—It Needs R&D

Most charities approach testing like an assembly line: run A/B tests, find the winning message, roll it out. But that’s not enough. Fundraising needs its own version of basic research—experiments designed not just to find short-term winners but to uncover why donors behave the way they do.

This means running R&D-style tests that include:

• Survey data: Measuring psychological traits (like identity, altruism, or reactance) that might explain why donors respond differently to the same message.
• Experimental variations: Testing beyond just “which message raises more?” to include variations that test the mechanisms behind behavior.
• Longitudinal analysis: Looking at whether certain nudges work in the short term but hurt retention in the long run.

Without this level of testing, fundraisers are flying blind—optimizing for the next gift without truly understanding what drives donor behavior at a deeper level.

Test, Learn, Adapt

The key takeaway? The same behavioral science principles that drive consumer choices don’t always translate to fundraising. Sometimes they work. Sometimes they backfire. And even when they work, they don’t work for the same reasons, or they don’t work the same way for all donors.

That’s why testing is essential. But more than that, the type of testing matters. If we only chase quick wins, we miss the chance to build a deeper understanding of donors.

Fundraising isn’t just another branch of marketing—it’s deeply personal, shaped by values, identity, and emotion. The best way to optimize for donors isn’t to copy-paste market strategies. It’s to understand why people give—and continuously learn from them.