The Psychology team at Tutor2U have been listening to one of our favourite podcasts this week, ‘The Rest is Science’ with Hannah Fry and Michael Stevens, which often has Psychology-related content. Recently, they have focused on something called the ‘deficit model’, which is the focus of this Psychology in the News post.

Let’s start with a question: if you gave someone all the facts about a topic such as climate change or following a healthy diet, do you think they would change their behaviour? If your answer is ‘yes’, you’re not alone. Those who work in Public Health (professionals who work to promote the health of whole populations) believed this for many years. However, this logical approach is not how a typical person makes decisions.

The deficit model is the idea that if the public isn’t acting on scientific evidence, it must be because they lack information. If we can close the gap in their knowledge (or ‘fill in’ the deficit), the correct behaviour will follow. However, many years of research show that giving people more facts rarely changes what they do.

For example, the UK government has spent millions on anti-smoking campaigns filled with facts and statistics about cancer risk. People who smoke are often already aware of these risks. The deficit model would predict that this information should lead to them stopping smoking, but it isn't that simple.

In her podcast, mathematician and broadcaster Hannah Fry explores the science of how we make decisions. The conclusion is that we are not rational calculators of risk and evidence. We are emotional, social and shaped by our identities as well as past experiences.

Fry states that rather than thinking ‘here are the facts, what should I conclude?’, we tend to think ‘here are the facts, how do they fit with what I already believe and what do the people I trust think?’.

This is supported by the idea of ‘motivated reasoning’ (Kahneman, 2011), which is when we unconsciously seek out information that confirms what we already believe and dismiss information that challenges it. Facts get filtered through our existing worldview, not the other way around.

So, what does work when trying to get people to change behaviour? The UK-based Behavioural Insights Team (BIT) suggest three evidence-based approaches tend to be most effective.

The way a message is framed produces very different responses. ‘90% survival rate’ feels better than ‘10% mortality (death) rate’, even though they're identical. Furthermore, who delivers the message is also important. We are more likely to take information seriously when it comes from someone we trust (for example, a GP or friend), not just an ‘expert’. Finally, a narrative or convincing human story produces empathy in people, and this makes messages more memorable than data.

References:

The Rest is Science podcast: The Reasoning Test Psychologists Still Can’t Explain (accessed 24.4.26)

Behavioural Insights Team (BIT) Going with the grain: influencing behaviour through public policy (accessed 25.4.26)

Kahneman, D. (2011). Thinking, fast and slow. Farrar, Straus and Giroux.

ANSWER THE FOLLOWING QUESTIONS!

1. One of the reasons we do not simply change our behaviour in response to facts is motivated reasoning. Which feature of the cognitive approach aligns closely with this concept?
2. Use your knowledge of normative social influence to explain why someone might not stop smoking, even when they are presented with the facts about the consequences to their health
3. Identify the key elements which make a minority successful in changing the views of the majority.
4. How could minority influence be used to encourage people in a particular workplace to eat a healthier lunch, rather than simply presenting them with statistics about healthy eating?
5. Imagine you have to launch your own campaign to encourage individuals to have a vaccine against the next global pandemic. How would you ensure that whole populations took up the offer of the vaccine?