The number one rule of great communications is: know your audience.
Yet most communicators still design messages for how they wish people thought, not how they actually do.
Decades of behavioural science research reveal that most human decisions are fast, emotional and unconscious - so why are so many campaigns still written for the slow, logical brain?
Here are ten behavioural science principles every communicator should know, with my ranking from least to most important:
10. Framing and anchoring
Framing is where people’s choices change depending on how options are presented, even when where they are logically identical.
For example, people are more likely to choose a surgical procedure with a 90% survival rate than one with a 10% mortality rate. Same fact, different framing, different response.
Anchoring is where judgements are influenced by a reference point. Anyone buying a car or negotiating a salary should know the starting point has a big influence on what feels like a reasonable settlement.
Extraordinarily, anchors still have an effect when people know the anchor is completely irrelevant.
For example, participants in a study were asked to estimate the proportion of countries in the United Nations that are from Africa. Before estimating, the participants observed a roulette wheel that stopped on either 10 or 65. On average, those whose wheel stopped on 10 guessed the answer was 25%, whereas those whose wheel stopped on 65 guessed at 45%!
Discounts are a common example of anchoring in communications. The original price serves as the anchor and the discounted one seems a bargain.
9. Authority bias
Far from having had “enough of experts”, we actually trust and follow the lead of those we perceive to be authority figures.
In a disturbing experiment conducted by Stanley Milgram in the 1960s participants were instructed by a researcher to administer what they thought were increasingly severe electric shocks to another participant when that person answered questions incorrectly.
In reality, the person who appeared to be receiving the shocks was an actor. But participants didn’t know that. Despite hearing their screams, most continued administering shocks when instructed to do so, demonstrating the powerful influence of authority figures.
In a variation of the experiment, obedience levels dropped from 65% to 20% when the instruction to continue with the shocks was given by an ordinary member of the public wearing plain clothes rather than a researcher dressed in a lab coat.
The experiments reveal humans’ dangerous capacity to abandon our humanity when subject to institutional authority. But as well as being aware of the dangers, this bias can also be applied for public good.
The Edelman Trust barometer shows that people still trust scientists and teachers far more than CEOs, politicians, or journalists.
During the Covid pandemic, the Prime Minister was often flanked by the Government’s Chief Scientific Adviser and Chief Medical Officer in press conferences. Not just because they could answer more technical questions, but because their presence would make important public health advice more trustworthy.
8. Commitment
Once people commit to something publicly or privately, they’re more likely to stick with it. If you have ever been asked at the end of a learning session to commit to one thing you will do differently next week, this is why.
In the same way, a charity that persuades you to wear a small badge or wristband knows that your visible commitment makes you more likely to donate again later. Communicators who can create moments for audiences to say “yes” in small ways make bigger commitments more likely.
Even after privately committing to a behaviour you feel psychological pressure to be consistent. This is why apps like DuoLingo get you to commit to a certain number of lessons, tell you how many days of a learning streak you’re on, and show you your place on a leaderboard.
My wife and I once debated whether we should drive 12km in a remote part of Africa in the hope that she might find mobile reception and keep her 263 week Peloton streak alive. Commitment is a powerful force!
7. Defaults and nudge
Defaults are where people tend to stick with existing options. The most powerful example of this is the transformation of UK pensions through auto-enrolment. Rather than asking people whether they wanted to opt-in to a workplace pension scheme the Government changed the rules so that people were asked whether they wanted to opt-out. This increased private sector pension membership from 32% in 2012 to 75% by 2021, increasing annual pension contributions by an astonishing £20 billion.
Nudge builds on defaults by arguing that making small changes in “choice architecture” can dramatically affect behaviour. Some men’s urinals have a small image of a fly etched into them. I could never work out why. The answer is that it reduces ‘spillage’ because men instinctively aim at the target. Crude but effective!
Sometimes the best communication involves changing the environment so that people barely notice they are being guided.
6. Habit and Cues
Much of what our brain does is not the product of conscious choice but of habit. Habits form when a cue in our environment triggers an automatic routine. For example, smokers light up when they have a coffee, commuters check their phone once they’re on the train.
For communicators the opportunity is to either break habits or use cues to create new ones. I was responsible for the Fire Kills campaign when I was at the Home Office. Testing a smoke alarm is a small task but one which is easily put off. By encouraging people to test their smoke alarm at the same time they changed their clocks twice a year the campaign connected the activity to a cue to create a new habit.
The Stoptober campaign attempts to break the habit of smoking. It did so by creating a new moment in the year for people to stop smoking outside of the usual opportunity around the New Year. It took the knowledge that smokers are five times more likely to stop for good if they make it to 28 days to create a month-long behavioural journey that felt more manageable than making a permanent commitment to quit.
5. Loss aversion
We hate losing twice as much as we like winning.
For example, If I told you: “I’m going to toss a coin. If it’s tails, you lose £10".”How much would you have to gain on heads in order for you to take this gamble? Most people say they would expect at least £20 to consider it worth risking £10. This is twice the upside on a 50:50 bet.
Loss aversion is why offers that “must end soon” are more effective in communications that the same offer being available permanently. Fear Of Missing Out is also classic social media behavioural technique that plays on this principle. It also means that communications that focus on negative consequences tend to be more motivating than those that focus on gains - people are more likely to be motivated by short-term pain than long-term gain.
4. Cognitive dissonance and confirmation bias
When people are confronted with information that conflicts with their beliefs, they experience discomfort known as cognitive dissonance. To reduce that discomfort, they often dismiss or reinterpret the new information rather than change their mind.
Confirmation bias reinforces this tendency: we give more weight to evidence that supports what we already believe and discount what contradicts it. In experiments, people rate identical evidence as more credible when it supports their side of a debate. For example, during the pandemic people who strongly supported or opposed lockdowns were more likely to interpret new data as proof that lockdowns did or didn’t work, rather than change their minds.
For communicators, this explains why seeking to change someone’s beliefs by proving them factually wrong rarely works. If your message threatens someone’s identity or worldview, it will bounce off. The challenge is to find shared values, trusted messengers and narratives that allow people to update beliefs without feeling attacked.
You can’t bludgeon people into changing their minds with data; you have to make it feel safe for them to.
3. Cognitive ease and availability
The easier something is to process, the more true and trustworthy it feels. Brevity is the secret to great communication.
If you turn your communications narrative into three paragraphs, then three sentences, then three words (eg Get Brexit Done), it won’t only be more memorable - it will also be perceived as more important and trustworthy.
Availability bias is a mental shortcut which means we tend to ascribe more importance to something that we can easily recall. This applies to more than just messaging.
For example, people overestimate the dangers of flying after hearing about a plane crash even though driving may be riskier. The easier it is to recall the consequences of something, the greater those consequences are often perceived to be.
2. Social Proof
We are very strongly influenced by what others are doing. This is one of the most powerful tools available to communicators. In fact, the whole of social media is pretty much based on it.
In his book ‘Influence’ Robert Cialdini explains how he discovered that a message telling hotel guests that “the majority of guests who stay in our hotel reuse their towels” resulted in a 28% increase in the number who chose not to have new towels. It was more effective than any rational appeal or other message, such as the environmental impact of washing towels.
If you think about it, this is really quite striking. The people did not personally know the other people who were reusing their towels, and they did not have to interact with anyone so there was no direct peer pressure to conform. But a simple change of message resulted in a drastic change in behaviour when based on what other people were reportedly doing.
Relatability and social identity theory takes this further by arguing that we are more likely to be persuaded by people we like or we identify with or who we have interacted with previously.
For communicators, this means the messenger matters as much as the message. This is why brands work with content creators who are already trusted. Why a recommendation from a trusted friend can outweigh expert advice. And why we place weight on testimonials from people like us when buying goods or services.
1. System 1 and System 2
You have probably heard of Daniel Kahneman’s book ‘Thinking Fast and Slow’. In it he explains how we use two modes of thought. System 1 is fast, intuitive and emotional. System 2 is slow, deliberate and logical. Most of the time we default to System 1.
The psychologist Jonathan Haidt described the interplay between our rational and emotional selves as like the “elephant and the rider”. The rider, sitting atop the elephant and holding the reins, appears to be in control.
He or she represents our conscious, analytical and rational brain. Our conscious mind can plan, reason and make decisions. The elephant on the other hand, is our intuitive and instinctive side. It is driven by emotion: feelings, desires and gratification.
While our rational side influences behaviour and direction, it is our emotional side that is truly powerful.
This matters for communication because making an argument solely to the rider (a rational argument based on facts or statistics) will not succeed over an argument built on emotion and instinct.
Anytime the elephant and the rider disagree about which direction to go in, the elephant is going to win. Communicators need to design messages that work intuitively first, then back them up with rational evidence.
These ten principles reflect the way that our brains are wired. But the modern media environment amplifies their importance. In a world where algorithms shape attention and trust is in short supply, communicators who know how to work with the grain of human psychology are more likely to cut through.
In future posts, I’ll explore some of these concepts in more detail and show you some practical frameworks for incorporating them into your next campaign.
Simon
Deeper Cuts
While researching this article, I came across this excellent list of the most relevant biases in behavioural economics from The Decision Lab.
Relatability, the halo effect, loss aversion and social proof see Cialdini, R. B. (2008) Influence.
Stanley Milgram’s authority bias experiments see McLeod, S. (2025) Stanley Milgram Shock Experiment.
Defaults and Nudge, see Thaler, R. H., & Sunstein, C. R. (2009), Nudge; and Karjalainen, H. (2022) On a roll? The first decade of automatic enrolment into workplace pensions.
Anchoring and framing, see McNeil, B. J., Pauker, S. G., & Tversky, A. (1988) On the framing of medical decisions.
System 1 and 2 thinking, see Kahneman, D. (2011) Thinking, Fast and Slow and Haidt, J. (2007) The Happiness Hypothesis
