146 people were asked to rate identical cookies that were either presented in a jar as scarce or in abundance. They were then asked how likely they would be to want to eat a further cookie.

When scarce, the cookies were rated as more desirable and having a higher value. They were also seen as more valuable when going from an abundant state to scarce than when always scarce.

Scarcity comes in 4 flavors: Quantity, Time, Access & Rarity.

Control quantity. To increase perceived value of your product, release it in smaller and diminishing quantities, emphasizing its finite nature.

Restrict time. When the clock is ticking and we’re overwhelmed, we take mental shortcuts that speed up decision-making. Motivate customers by emphasizing the limited time remaining in which to act.

Limit access. Restricting access to your products or services will increase desire and perceived value. Do this selectively for certain features and / or customer segments.

32 dog-phobic children were split into 3 groups and shown 8 videos of either one child playing with a dog,  many children with different dogs or no dogs, and then asked to interact with a dog themselves.

Those who watched another child play with a dog performed far better. Those who watched many children also kept this up a month later.

Provide mental shortcuts through the judgements of others; the more people, the more persuasive.  First-time consumers of your product will benefit the most from this approach. 

Persuade with similarity. We're most influenced by those who we deem similar to ourselves. Communicate characteristics relevant to that segment, such as proximity, gender / age, profession or social class to successfully direct behavior. 

Use role-models. Understand the emotional drivers of your audience and seek out positive, aspirational individuals to direct specific consumer decisions and reinforce behaviors.

96 people were told they’d be given some ground beef to taste, with half told it’d be  “25% fat” (negative frame) and half told it’d be “75% lean” (positive frame). They were then asked to rate the quality of the beef out of 7.

‍Those presented with a positive frame rated the beef as higher quality than those presented with a negative one.

Create a frame using context, words or imagery to help others  to see things according to your needs.  Wildly different perceptions are made possible by reframing the same evidence.

Reframe statistics as factually-accurate positives against competitors.  Facts are dramatically reinterpreted when set amongst different data. 

• Create a fear of missing out. We’re more likely to take up a special offer when the marketing message is framed as a potential loss than a gain (Gamliel and Herstein, 2012). 

249 supermarket customers were invited to one of two tables, displaying either 24 jams or 6 jams. They were then asked how attractive the jams were and observed as to whether they bought one.

The results found that though customers considered the 24 jams more attractive, they were far more likely to buy when there were only 6 jams to choose from.

Reduce choice difficulty. If customers are time-poor, reduce the number of dimensions along which your products are compared. Present choices in an organised, non-random order, especially with visual layouts. 

Tidy up choice relationships. Highlight one dominant option, align the attributes along which products are compared, and eliminate products from your range that overly complement each other to decrease deferral and increase purchase likelihood.

Adapt to product expertise. Who is your audience? To what extent can they weigh up the benefits of each possible choice? Experts prefer more choice and the lesser-informed crave less.

Build around intent & focus. Intent: are they buying or merely browsing? If browsing, they’re not making a decision, and are less likely to feel overloaded. Focus: a single purchase or a bundle? Bundlers want more options, but Singles want fewer.

150 teachers  in Chicago were either offered a cash incentive up front or after their students’ math test, with better results leading to more money. Subject to results, the money-up-front group would suffer deductions for unmet targets to create a feeling of loss aversion.

Teachers receiving  money up front were found to have much better results than those rewarded at the end.

Increase conversion with trial offers. Though some consumers might not be willing to pay the market price for your product, they may pay the market price to avoid it being taken away.

Offer delayed payments to shift consumers’ judgements from paying to get the product to paying to avoid losing it. For instance, a month delay in paying subscription fees. This means that any extra budgetary cost is then re-estimated as a question of how it can be fitted into an existing budget.

Replace faulty products immediately with an identical or superior model (Novemsky & Kahneman, 2005). Doing it quickly will limit the pain of loss aversion, which builds over time (Strahilevitz and Loewenstein, 1998).

153 New York pedestrians were approached by someone dressed as either a civilian, a milkman or a police officer and were asked to help out a stranger by covering the cost of his / her parked car ticket.

The more authoritarian the uniform, the higher the chance they’d give the money. The civilian succeeded only 33% of the time, whereas the police officer managed 89%.

Determine an authority figure with relative expertise in relation to the group and behavior you’re looking to influence. Ensure that the individual is credible and trustworthy.

Communicate their authority clearly. For instance, using authority indicators like “Doctor,” “Judge,” “Award-winning” etc. Complementing this with a suitably-dressed photo of said individual will make any request much more effective. Add a quotation too.

Compliance varies depending on demographics. Older people are more compliant than younger people, for instance. For the young, use culturally-relevant aspirational models to mask authority whilst also nudging desired behavior. 

161 people were told that they’d just moved to a new US state and that here, the default was (or wasn’t) to be an organ donor. They were then asked to accept or change this donation status.

Results showed that only 42% donated when the default was to opt out, but 82% when defaulted to opt in.

Defaults are powerful. They’re chosen because consumers take mental shortcuts (especially when tired) and because there’s implied trust that they’re the ‘right’ choice. Defaults also act as a reference point against better or worse options. (Dinner et al., 2011). 

Defaults can be set around anything: from the standard package you offer to new subscribers, to the pre-set top-up amount for your mobile wallet, to whether each order of pizza should come with salad. Each default can dramatically affect conversion levels and behavior.

Get the balance. Ensure your defaults feel natural and in line with consumer aspirations. The more extreme the default you set (i.e. defaulting to the most expensive option), the more effort consumers will expend weighing up the cognitive / emotional costs of not choosing the default, impacting their experience and reducing overall trust.

34 people were split into 3 groups and each told to unscramble a list of either rude, polite or neutral words. After, they were told to see the researcher, who was engaged in a fake discussion with a peer. They were then timed with how long it took before they interrupted.

63% of those primed with rude words interrupted within 10 minutes, compared to only 18% of the polite group.

Prime with words that highlight the positive emotional effect of using your goods or services. For example, Spotify could prime users of its Discover Weekly playlist by using words that highlight its uniqueness or repeat gift-giving benefits.

Combine with images Coca Cola created an advert in Italy called ‘Open the happy can’ that primed potential buyers with a simple smile that was revealed upon opening. This was done in order to create an associative link between happiness and drink consumption, as well as providing a means of positive feedback for the consumer. 

 Keep it subtle. Prime too aggressively and the effect will weaken, or even lead to an unwanted Contrast Effect, where we’ll subconsciously reject and seek out opposites to the prime.

212 Iowan households had their energy use tracked for a year with the aim of reducing it. Half who agreed to reduce were told their name would be shown publicly in the local paper.

Those publicly committing demonstrated a 15.5% larger average reduction in energy use over winter.

Anchor any request with a leading question that supports others’ positive judgements of themselves or their past decisions.

Start with a small request that allows the respondent to remain consistent with their answer to this question. Commitments are self-reinforcing and build over time, so build slowly on this initial commitment with further, larger requests such as a future product purchase.

Make it public. Declaring an opinion to others on a subject or product will compel consumers to remain consistent with and even strengthen this opinion in future, especially if written down. e.g. asking others to tweet why they love a product will strengthen attachment to it, as well as fostering social proof for others.

47 subjects were given around 20 small, manual tasks to complete, one at a time. Experimenters randomly interrupted completion of half of these tasks. After, subjects were asked to recall as many tasks as possible.

There was a 90% higher recall of incomplete and interrupted tasks than those completed.

Make important task completion frictionless. If customers leave your site without finishing their order, make it effortlessly easy to get that completion feeling, such as allowing for completion with a single click, tap or swipe. 

Focus on completion’s emotional release. Providing reward incentives for task completion actually demotivates consumers. Instead, remind them not just of the product they’ve not yet bought, but of the feelings that this ‘purchase task’ will unlock. 

Make known campaigns incomplete and interactive. Greater familiarity with an advert increases consumer ability to complete an interrupted ad message. Active participation also boosts ad memory (Heller, 1956). So if your popular campaign’s reaching its end, consider a special second follow-up version that allows for active participation in completing the ad message. 

84 people were shown an ad for a known clothing brand that they either had an existing loyalty to or not, written either assertively or not. Based upon the ad, they were then asked how much from a $25 gift card they'd spend.

People spent less money after viewing an assertive ad next to a non-assertive ad, especially when loyal.

Don’t misuse behavioural principles.

‍We've seen a rising use of faux-scarcity to create an uneasy sense of urgency as well as an aggressive use of Defaults that aren't in customers' best interests. Such applications turn positive activities, like booking a holiday into ones riddled with stress.

Give some control (Miller et al., 2007).

Having a feeling of choice can reduce feelings that our freedoms are being taken away. Mix Autonomy with Certainty by reminding of the inevitability ahead while granting other areas where you can give back control in meaningful ways.

Give lots of warning up-front

‍If you're planning a big change that will clearly trigger reactance (Richards and Banas, 2015), giving time for the news to sink in, let people familiarise themselves with the new, uncomfortable normal will then reduce reactance when the change does come about.

105 people were shown an online promotional offer, with the final offer value of 40% revealed either immediately or only at checkout.

Those in the extended curiosity condition were more likely to buy with the promotion than those who were told of the offer value immediately.

…curiosity will always be effective.

A recent campaign by Cancer Research UK to fill missing letters of the second-most common cause of cancer led to a 22% increase in its awareness. 

How can you use curiosity to drive a desire to learn about a new product or important message?

Create positive curiosity.

Vacation company srprs.me let you choose the number of people, dates and continent. You then get a scratch card to reveal your destination…but only at the airport!

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Use to convert free to paid.

‍Popular dating app Bumble uses curiosity to drive conversions. People who’ve already liked you are shown, but with their faces pixelated and no further information shown. Users are then prompted to buy BumbleBoost to close the information void.

408 people were shown one of three versions of a shampoo advert. The control just had the words “Say bye-bye to your dandruff” with an image of a couple. The two metaphor versions both had “You may erase anything unwanted” with either an eraser (implicit) or the bottle of shampoo (explicit) rubbing out words on a blackboard.

Results showed greater purchase intentions for the product with either metaphorical ad.

Leverage our existing understanding of the world for new ideas or concepts. Complicated ideas are best understood through existing ones. What analogies can you draw that your customers can relate to?

Easy metaphors aren’t always best. Research has found that metaphors with a little complexity are fun and act as a mild problem to solve. Use with Curiosity and Humor.

Reserve this for known brands or products; for new or abstract technology, keep metaphor complexity low.

Metaphors come in different flavors:

Juxtapositions: two images next to one another;

‍Fusions: mixing two concepts into a single one; or

‍Replacements: switching one thing for another. 

Just make sure that you harness real world understanding to help ground your new idea. 

40 people were split into two groups and shown a list made up of either 10 unrelated items (a number, a syllable, a colour, a word etc.), or 9 numbers and one isolated syllable placed second in the list. After a 10-minute reading task, both groups were then asked to recall the list.

Those in the isolation group successfully recalled the syllable 70% of the time, as opposed to 40% in the control.

Use complementary contrast. When showing a list of similar products (e.g. beer), weave in a contrasting product to create complementary cross-selling (e.g. nuts) or up-selling (premium beer) opportunities. 

Use contrast for clarity. If you offer a range of products, draw the undecided consumer to a strategic option, preventing choice overload and assisting sales. How might customers become overwhelmed with your range? How can you create a clear sense of contrast that avoids this negative feeling?

Contrast through context. If your brand is familiar, how can you place it in relevant yet unexpected contexts to heighten recall? For instance, British food delivery service Deliveroo could have a movie tie-in shot in London, where its turquoise drivers whiz by in the background 2-3 times over the course of the narrative. 

218 people were split into 3 groups, given either a coffee mug or a chocolate bar and told they could swap their item for the other; or given neither and told they could choose either.

Those who’d been endowed with either item were far more likely to stick with it than those who were given neither.

Perceived ownership is powerful, allowing consumers to attribute increased value and emotional connection on what you’re offering, creating a strong desire to buy that increases over time.

It’s driven by a price gap between how much we’re willing to pay for an item and the price we’re willing to sell it for. This is due to a mix of Loss Aversion, Framing (i.e. buyer or seller) and the evolutionary advantage of overvaluing our tradable possessions. Doing so increases our resources and chances of survival.   

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Allow people to feel ownership of a product prior to purchase. Examples include: making it effortless to add that product to their basket, visually personalizing a product early in the ordering process, highlighting how soon it could be at your door or allowing free week-long test drives of that car you’ve always wanted.

90 people were asked to solve 50 puzzles in either 10 or 40 minutes. A time-saving notification stating that “This question isn’t worth any points. Press A to skip” would pop up for half the puzzles.

Results showed that the time-scarce group ironically were more likely to miss the time-saving notifications due to their heightened focus on task completion.

‍Time Scarcity increases conversion under a few conditions

Make sure your use of it is on-brand, authentic and not overly-aggressive to avoid harming long-term trust and loyalty.

A big clock with red flashing text may boost sales in the short-term but risks damaging brand perceptions in the longer term and will lead to Reactance in the more behaviorally-aware and in more mature markets with stronger competition. 

Use time windows for excitement.

Particularly for experiments with new ideas or for seasonal Limited Editions. Starbucks’ Unicorn Frappucino was on sale for 5 days only. It sold out in just 3 and generated 160,000 Instagram posts. 

Develop novel ways of saving people time.

‍People who spend money on time-saving purchases report greater life satisfaction (Whillans et al, 2017). 

Amazon and Sainsbury’s are exploring no-queue, no-till shopping. Just scan on the app and leave. How can you free up even a few minutes of our most precious commodity?

88 household individuals were split into three groups and  asked to either wear a badge supporting a  charity, asked to wear one along with another family member or not to wear at all. That same evening, all groups were then asked for a financial donation to the charity.

Those who were first asked the small request were far more likely to go on and donate money than those who weren’t.

Start with a question promoting reflection on one’s values. Their answers will create a desire to be consistent with their beliefs.

Have people perform a small related action. e.g. People who put a small “Drive carefully” sign in their window are more likely to follow the instruction than those who merely say they will. Frame it as a social norm.

Prime the ‘helpful’, ‘cooperative’ ‘supporter’ with positive feedback prior to a future request. 

Make the target request a continuation of the initial one. The more similar the activity, the greater success. Also balance your request sizes. If the initial request is too big, people won’t do it, never getting to the target request. But too-small tasks will widen the gulf between the two.

11,912 members of a gym were surveyed over 442 days for their attendance.

Results showed that, next to the baseline, the probability of people going to the gym increased at the beginning of the week, month and semester, showing our higher in-built level of motivation at the start of new time periods.

Motivate around fresh start moments. 

How can you help people achieve their dreams by communicating around multiple time chunks, such as the start of the week, month or year, or even personal events like birthdays, graduations or job changes? 

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Target one-shots.

‍Fresh starts are particularly good at helping people make one-off decisions that perhaps they'd been delaying, such as getting that flu jab. What single task can you help people do around new time periods?

Use to overcome failures.

‍There are countless fresh start opportunities to help people who have let good habits slip. Frame it as a "new you", which gives an opportunity to separate themselves from past failures. Get them started by being empathic and having them Commit to a Tiny Habit.

375 mountain hikers were approached as they passed a cheese sales counter and asked to buy a large piece, with all rejecting it. They were then offered a piece half in size and cost and split into 4 groups: 1 - Simple DITF;  2 - a verbal concession that large was too big; 3 - credibility by wearing a traditional uniform; and 4 -  2+3 combined.

Purchases were much higher with DITF, especially carried out by a credible salesperson conceding verbally.

Verbally emphasize the concession of the target request over the initial one. This is vital - hearing the salesperson empathize and adjust their request is required for the consumer to reciprocate and accept.

Only use in physical sales situations. It’s unlikely to work where there is no direct contact between buyer and seller (e.g. online auctions), due to the lack of verbal concession and face-to-face interaction. It’s best used in an in-person context where negotiation is key (car showrooms, charitable giving, B2B contracts etc).

Sizes matter. Don’t make your initial request too high, as consumers will use it to justify their rejection of the target request (Wang et al, 1989). Also ensure that the reduction of the target feels significant enough for the consumer to justify a decision change. 

850,000 teachers' retirement plans were assessed. Each teacher's main decision was to divide their pension between two funds: one low risk (bonds) and one high risk (stocks). They could switch between the two at no cost.

Results found that despite the massive differences in rates of return between the two funds, only 20% ever switched from their initial fund allocation.

What's the status quo in your situation?

‍Build a strategy around identifying and removing the practical and emotional switching costs that are preventing change.

Make it exciting!

‍It isn't enough to just remove the barriers. Offer a Contrasting view of the net gain of the change, painting a clear, positive picture with a personalized Goal Prime showing them how their life will be better.

Make it effortless.

‍Use Foot In The Door with a Tiny Habit to help users take the first positive step.

Identify and work with a group of 'change-makers'; those with some Authority who are most ready to adopt and embrace change.

Share their positive Stories with others more averse.

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Check your Defaults.

You’re setting them everywhere, sometimes without thinking. These strongly influence the status quo. What new behavioral goal are you looking to foster in your users? Update your defaults to suit.

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22 students were shown a range of graduate yearbook photographs a varying number of times for 2 seconds each. They were then asked how much out of 7 they liked each person.

Results showed that the more times they’d seen a given graduate photo, the more they liked them.

Expose the unknown within the known.

Create trust for new, unfamiliar products by sample-bundling with existing products. UK supermarket, Waitrose did this expertly when it first introduced kiwi berries, managing consumer unfamiliarity by bundling a small free sample with large packs of trusted blueberries. This approach is known as a Foot In The Door.

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Exposure first. Behavior change second.

Reduce people’s Risk Aversion by taking a staged approach to rolling out new ideas or policies. Instead of starting by looking to change behavior, just expose people to some introductory aspect of it, using the Spacing Effect to spread experiences out across time and environment. Let it become familiar for a while before making requests.

Overcome your own Confirmation Bias...

...by exposing yourself to new viewpoints. Though you may not agree with all you hear, you'll develop a skill to see common ground in an increasingly-polarized world.

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23,946 cafe hot drink sales were studied over 14 weeks. For the last 4 weeks, customers were shown a sign stating that “guests are changing their behavior and more and more are switching from the to-go cup to a sustainable alternative. Take part in this: choose a sustainable cup and help to protect the environment.”

Results showed that customers used 17.3% more reusable mugs over to-go cups after dynamic nudging.

Drive change by showing relative growth.

‍New behaviors tend to start small, so stating absolute percentages isn’t persuasive. Instead, reframe the change as a dynamic movement increasing over time to create a means to 'pre-conform' with this inevitable future (Sparkman & Walton, 2017).

Bolster with the 25% Rule...

...where new behaviors tend to become the norm once at least a quarter of a group adopt them. Boost change success by recruiting a group of change-makers to create, broadcast and maintain this initial effort.

Combine existing financial nudges with dynamic norms.

‍The cafe in the study was already charging €0.10 for a takeaway cup but they were able to improve behavior even further with this cheap, efficient and new nudging method...and so can you.

121 students were shown one of 3 adverts for watch brand Swatch. Either a control with no sales event, a limited-time sale (6 days) or one limited in quantity available (100) triggering competition. They were then asked how likely they’d be to buy the watch.

Those in the competition condition were more likely to buy than those under time pressure.

A little competition can be fun.

‍We are naturally competitive; where there are numbers, there are games. And though it shouldn't be the only driver of behavior change, subtle uses with measurable goals, leaderboards and appropriate Rewards can provide benefit. What positive behaviors do you want to encourage? Tell the Story of why the competition exists to help motivate further. Ensure that the competition also aligns with others' own aspirations.

Allow everyone to ‘succeed’, regardless of ability.

Bad competition creates clear winners and losers, which can demotivate the latter and reduce behavior change. Good competition includes ways to celebrate all efforts to reach a goal. Be sensitive to our desire to compare, e.g. only show individuals their relative place in a leaderboard.

Make competition team-based.

‍Too much competition can reduce internal motivation. However competing as broader teams can prevent this. Collaboration is a powerful tool to use with competition to foster new collective norms around the intended behavior.

105 people were split into two groups, put in a room with either a zesty scent in the air, or no scent. They were then shown a mug, and were asked to bid for it with real money.

Those in the scented room exhibited a higher average willingness to pay for the mug.

Keep environmental scents simple...

...unless it's the brand differentiator (e.g. Aesop, Neal's Yard). Much like visual stimuli, in-store scents deemed simpler result in both higher average spending and cognitive processing (Hermann et al., 2013).

Be authentic.

‍You'll risk triggering skepticism if you substitute a real side-effect of production for something fake (Lunardo, 2012), i.e. a freshly-baked scent in a store with no oven. Better to have a complementary or no scent than have consumers think you’re patching over an inferior product.

Consider a product scent.

‍What sort of feeling do you want to evoke upon unboxing? Adams & Douce (2017) provide a brilliant analysis of possible scents. Make it subtle, appropriate and apply it consistently to the entire range. e.g. Tech company Apple is notorious for the sweet scent experienced when opening up a new computer for the first time. Even though you can't see it, you remember it deeply.

468 people were randomly assigned to one of ten groups and shown a website list of ten hotels, each with the hotels in a different order. They were then asked to choose one.

Regardless of their group, more people chose hotels placed at the start and end of the list.

Position matters.

‍Why? Initial options are prioritized in our memory (Primacy effect). Then, we see a pattern, switch off in the middle and only at the end do latter options held in short term memory (Recency Effect) influence the decisions we make, so put your best stuff at each end.

End on a high.

‍Advertisers promoting benefits of their product should combine recency with the Peak-End Rule, finishing with a significant or unique feature to enhance recall, conversion and seal the deal with a positive Surprise.

Order = opportunity.

‍For ecommerce or aggregation sites, consider monetizing product positioning for the start and (paradoxically) end of your lists. Alternatively, design for and highlight conversion fairness with random ordering.

Over 27,000 Israelis were mailed a self-administering Colorectal Cancer test kit. The kit either included an “if–then” leaflet with instructions of when, where, and how to perform the test or a standard leaflet with no such planning instructions (control group). They were then asked 2 and 6 months later whether they took the test.

71.4% of the If-then plan recipients took the test compared to 67.9% of the control group meaning If-Then plans resulted in 6.6% more of participants taking the test.

Whether designing for yourself or for others, here's how to make an easy, effective If-Then Plan:

First, define the goal.

If for you, it might be to exercise more. If for others, it might be to reduce an organisation's water waste. What existing behaviour are you looking to reduce or reinforce? Alternatively, what new, aspirational behaviour might you be looking to foster?

Identify your "If" context

This will become the future cue or environment that we'll recognise. It'll provide a clear, detectable moment to do something, even if you're busy or tired. Pick scenarios that are encountered often (E.g. on a daily basis, like an office lobby) to boost effectiveness.

E.g. "If/when I'm waiting for the elevator…"

Choose a behavioural "then" response

This is the specific behaviour that will get you closer to the goal you defined. The easier it is to recall and do, the more it will be done. For instance, what small, relevant and easy-to-recall behaviour can I do IF I'm waiting for the elevator?

E.g. "I will take the stairs"

Planning these steps out in advance and defining exactly how one should respond in the situation creates a strong, repeatable link between seeing and doing.

E.g. "If I have to wait for the elevator, then I will take the stairs"

Note: If designing for others, to ensure it'll be easy and fits within the context you're designing for, consider roleplaying it out before you roll it out. Role before you roll, if you will.

Inform, do not instruct.

A vivid, relatable and subtly persuasive image or message will be more effective to change consumer behaviour, whereas instructing them could be met with reactance. Remove this threat to personal freedom by giving consumers more autonomy when they make decisions.

Ideally, If-Thens should be defined at least in part by the person themselves. However, there are creative workarounds; companies could set and share strategic goals, with employees writing their own If-Then Plans to help achieve such goals.