Think of the most significant decisions you’ve made in life.

Like getting married. Or buying a house. Or even quitting your job.

There’s a high probability that your age ended in the number nine at the time.

Two American psychologists Adam Alter and Hal Hershfield demonstrated this was more than just a coincidence after analysing three different data sets.

One set related to first-time marathon runners.

Those whose ages ended in nine were 48% more likely to enter a marathon for the first time than those in other age groups (they even ran 2% faster on average!).

The other two sets demonstrated that this phenomenon doesn't always lead to positive behaviour.

Examining data from, a dating site targeted at married people wanting to have an affair, found that amongst men there was an 18% increase in those wanting to enter into an illicit relationship.

Lastly, data from the US Centre for Disease Control and Prevention showed a 2.4% rise in suicides when people were on the cusp of entering a new decade.  

‘Nine-enders’ are more likely than other ages to make momentous decisions in their life because as they approach a new decade it forces them to reflect on the meaningfulness of their lives.

This time for change is an opportunity for businesses to target people.

Thanks to platforms like Facebook and Google you can easily target nine-enders. So, if you’re putting on a marathon or want someone to buy a new car or house, targeting nine-enders would be a smart place to start.

If you’re interested in learning more about how behavioural science can lead to more effective marketing then you will enjoy our course on Behavioural Science for Brands.

Pre-register by clicking on the course tile on our homepage and leaving your email address. You’ll be the first to know when it launches!

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