Researchers believe the reason behind this happiness is that the cash we’ve spent has afforded us more free time – a rare commodity in our frenetic and attention-strapped world.

Psychology professor Elizabeth Dunn and her team first divided a group of participants into two groups and gave each person an allowance of CA$40 (£25) to spend. One group were instructed to spend it on a material gift, such as a bottle of wine or a shirt, and the other group were told to invest in a service that would make their lives easier, from laundry services to help with tidying up.

This second group reported feeling more positive emotions at the end of the weekend, compared to the group who spent their allocated money on things.

"Buying yourself out of [tasks] like mowing the lawn or cleaning the bathroom — these were pretty small, mundane expenditures, and yet we see them making a difference in people's happiness," Dunn tells NPR.

The team's findings were supported by another larger survey they conducted of a group of 6,000 people in the States, Canada and Europe. Participants came with a wide range of incomes.

Time, not things: this is how money really can buy you happiness