Make Your Copy More Convincing (With the Appliance of Science)

I’m reading a fascinating book at the moment called Thinking, Fast and Slow by Daniel Kahneman, a psychologist, behavioural economist and winner of the Nobel Prize for Economics.

Since 1969, Kahneman has been examining the psychology behind decision-making and judgement and the book sums up decades of study into “how and why we make the choices we make”. In it he answers all sorts of questions, like why we think good-looking people are more competent, why judges are more likely to deny parole before lunch, and why we believe text written in bold type.

Kahneman begins by distinguishing between our two decision-making systems, which he calls System 1 and System 2.

System 1 is fast and automatic (we tend to call it instinct), System 2 is slower, logical, voluntary, and draws on what we know (or what we think we know) about the world.

He has some wonderful examples of how we rely on each system to process information and make decisions, which often lead us to the wrong conclusions because we’re not aware of their in-built prejudices.

If you’ve ever thought that ‘your instinct is always right’ think again! It’s not true, both systems often get it wrong.

How to make your copy more convincing

I’m particularly interested in how this affects copywriting but I’d recommend reading Thinking, Fast and Slow [the link takes you to Amazon] if you’re at all interested in human behaviour or want to learn how to make better decisions in life. Be warned though, the book is 450 pages of the teeny tiniest font you’ve ever seen!

Using behavioural economics in copywriting

Here comes the science bit – concentrate!


Marketers often repeat a piece of information or a ‘key message’ because it lodges information in the reader’s brain. It also, as Kahmenan explains, makes us believe what we’re reading.

Even if it isn’t true.

Psychologists have found that if you hear something often enough you believe it, whether or not it has any basis in fact because of what Kahneman calls ‘cognitive ease’, the amount of effort involved in processing the information.

If you hear or read a piece of information often enough, even if it’s complete nonsense, you’re likely to believe it because it sounds familiar.

As well as ‘repeated experience’ cognitive ease is created through:

  • the clear display of information (it’s easy to read)
  • primed ideas (you’re already thinking about something related)
  • being in a good mood (amazingly, even if you’re not in a good mood, having a pencil across your mouth forcing it into a smile tricks the brain into thinking you’re happy and has the same effect)

The consequences of cognitive ease are that what you’re reading and the process of reading it feels “familiar, true, good or effortless”. And because it feels familiar, you are less vigilant and don’t question what you’re reading.

System 1 reads the information and finds it easy to process with no obvious reason to doubt it or investigate it further so System 2 doesn’t examine it – and you believe it.

Bold type

Here’s a great example from the book. Read the two statements below:

Adolf Hitler was born in 1892.

Adolf Hitler was born in 1887.

Which one do you believe?

The first one I bet. How do I know? Because it’s in bold.

Neither of them is true actually, Hitler was born in 1889, but we’re more likely to believe the first sentence because it’s in bold type.

As well as being able to fool people into believing something which isn’t true you can use familiarity and cognitive ease to strengthen authentic marketing messages.


To reduce cognitive strain (the opposite of cognitive ease) – which makes people question what they’re reading – make sure that your copywriting is as easy to read as possible (layout tips you might find useful).

Here’s some more advice from Kahneman to encourage your readers to trust you:

  • Use high-quality paper and have as much contrast as possible between the colour of the writing and the background.
  • If you use coloured text, bright blue and red are more likely to be trusted than pale blue, yellow or green.

Straightforward language

One of my favourite pieces of advice is to always use simple language (here’s a blog on the subject) and there’s scientific evidence for this one too.

keep copywriting simple and straightforward

In his article, “Consequences of Erudite Vernacular Utilized Irrespective of Necessity: Problems with Using Long Words Needlessly”, Danny Oppenheimer (from Princeton University) refuted the myth that big words make you sound clever.

He showed that using longer words than necessary to explain familiar concepts is seen as a sign of low intelligence and poor credibility.

Make it memorable

Rhyme makes people believe you.

In a study cited by Kahneman, participants were asked whether a number of aphorisms were true. The first set of aphorisms they were shown rhymed, like ‘Little strokes will tumble great oaks’, the second set didn’t – ‘Little strokes will tumble great trees’.

And guess what? The participants believed the rhyming sayings far more than the non-rhyming ones.

So, it seems that a lot of copywriting advice has a scientific basis and works by creating cognitive ease, making it easier for us to process information and more likely to trust the writer.

Here’s a quick summary of how you can strengthen your message and make your copywriting more convincing:

  • Repeat your key points
  • Make sure that the layout is clear and easy to read
  • Use bold type and contrasting colours
  • Keep your language simple
  • Make it memorable

If you decide to give the book a go please let me know how you get on, and feel free to leave a comment below.


P.S. If you enjoyed this you might like my blog about Made to Stick by Chip & Dan Heath, which looks at what makes certain messages ‘sticky’.

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