I know exactly how the conversation will go.

I’m interviewing Chris, a 52-year-old man living a small coastal town, for the second time. We’ve been exploring the new checkout process for a client’s redesigned website. The new site isn’t performing as well as the company thought it would, so I’m exploring why and seeing what we can learn from competitors.

“Only 2 rooms left? They don’t expect me to believe that do they? You see that everywhere.”

I leave with a wry smile. The client won’t be happy, but at least the project findings are becoming clear. Companies in certain sectors use the same behavioral interventions repeatedly. Hotel booking websites are one example. Their sustained, repetitive use of scarcity (e.g., “Only two rooms left!”) and social proof (“16 other people viewed this room”) messaging is apparent even to a casual browser.

For Chris the implication was clear: this “scarcity” was just a sales ploy, not to be taken seriously.

My colleagues and I at Trinity McQueen, an insight consultancy, wondered, was Chris’s reaction exceptional, or would the general public spot a pattern in the way that marketers are using behavioral interventions to influence their behavior? Are scarcity and social proof messages so overused in travel websites that the average person does not believe them? Do they undermine brand trust?

The broader question, one essential to both academics and practitioners, is how a world saturated with behavioral interventions might no longer resemble the one in which those interventions were first studied. Are we aiming at a moving target?

The broader question, one essential to both academics and practitioners, is how a world saturated with behavioral interventions might no longer resemble the one in which those interventions were first studied.

This was the basis for a research project we completed in February 2019 examining reactions of the British public to a range of behavioral interventions. We took a nationally representative sample of 2,102 British adults, and undertook an experimental evaluation of some of marketers’ most commonly used tactics.

We started by asking participants to consider a hypothetical scenario: using a hotel booking website to find a room to stay in the following week. We then showed a series of nine real-world scarcity and social proof claims made by an unnamed hotel booking website.

Two thirds of the British public (65 percent) interpreted examples of scarcity and social proof claims used by hotel booking websites as sales pressure. Half said they were likely to distrust the company as a result of seeing them (49 percent). Just one in six (16 percent) said they believed the claims.

The results surprised us. We had expected there to be cynicism among a subgroup—perhaps people who booked hotels regularly, for example. The verbatim commentary from participants showed people see scarcity and social proof claims frequently online, most commonly in the travel, retail, and fashion sectors. They questioned truth of these ads, but were resigned to their use:

“It’s what I’ve seen often on hotel websites—it’s what they do to tempt you.”

“Have seen many websites do this kind of thing so don’t really feel differently when I do see it.”

In a follow up question, a third (34 percent) expressed a negative emotional reaction to these messages, choosing words like contempt and disgust from a precoded list. Crucially, this was because they ascribed bad intentions to the website. The messages were, in their view, designed to induce anxiety:

“… almost certainly fake to try and panic you into buying without thinking.”

“I think this type of thing is to pressure you into booking for fear of losing out and not necessarily true.”

For these people, not only are these behavioral interventions not working but they’re having the reverse effect. We hypothesize psychological reactance is at play: people kick back when they feel they are being coerced. Several measures in our study support this. A large minority (40 percent) of the British public agreed that that“when someone forces me to do something, I feel like doing the opposite.” This is even more pronounced in the commercial domain: seven in ten agreed that “when I see a big company dominating a market I want to use a competitor.” Perhaps we Brits are a cynical bunch, but any behavioral intervention can backfire if people think it is a cynical ploy.

Heuristics are dynamic, not static

Stepping back from hotel booking websites, this is a reminder that heuristics are not fixed, unchanging. The context for any behavioral intervention is dynamic, operating in “a coadapting loop between mind and world.” Repeated exposure to any tactic over time educates you about its likely veracity in that context. Certain tactics (e.g., scarcity claims) in certain situations (e.g., in hotel booking websites) have been overused. Our evidence suggests their power is now diminished in these contexts.

Two questions for the future

In our study, we focused on a narrow commercial domain. It would be unwise to make blanket generalizations about the efficacy of all behavioral interventions based on this evidence alone. And yet nagging doubts remain.

#1: Like antibiotic resistance, could overuse in one domain undermine the effectiveness of interventions for everyone?

If so, the toolkit of interventions could conceivably shrink over time as commercial practitioners overuse interventions to meet their short-term goals. Most would agree that interventions used to boost prosocial behavior in sectors such as healthcare have much more consequential outcomes. In time, prosocial practitioners may be less able to rely on the most heavily used tactics from the commercial domains such as social proof and scarcity messaging.

#2 : How will the growing backlash against big tech and “surveillance capitalism” affect behavioral science?

Much of the feedback from the public relates to behavioral interventions they have seen online, not offline. Many of the strategies for which big tech companies are critiqued center on the undermining of a user’s self-determination. The public may conflate the activities of these seemingly ubiquitous companies (gathering customer data in order to predict and control behavior) with those of the behavioral science community. If so, practitioners might find themselves under much greater scrutiny.

Feedback loops matter

There probably was never an era when simple behavioral interventions gave easy rewards. Human behavior—context-dependent, and driven by a multitude of interacting influences—will remain gloriously unpredictable.

Marketers should design nudges with more than the transaction in mind, not only because it is ethical or because they will be more effective over time but also because they bear responsibility toward the practitioner community as a whole.

The lesson I take from our study? Feedback loops affect the efficacy of behavioral interventions more than we realize. Just because an intervention was successful five years ago does not mean it will be successful today. Practitioners should pay as much attention to the ecosystem their interventions operate in as their customers do. There’s no better place to start than spending time with them—talking, observing, and empathizing.

We should also consider our responsibilities as we use behavioral interventions. Marketers should design nudges with more than the transaction in mind, not only because it is ethical or because they will be more effective over time but also because they bear responsibility toward the practitioner community as a whole. We owe an allegiance to the public, but also to each other.