We love to talk and want to be listened to, but we stand less and less chance of being believed

People love propagating information and sharing opinions. You can see this online: every day, 4m new blogs are written, 80m new Instagram photos are uploaded and 616m new tweets are released into cyberspace. It appears that the opportunity to impart your knowledge to others is internally rewarding.

A study conducted at Harvard University found that people were willing to forgo money so that their opinions would be broadcast to others. We are not talking about well-crafted insights here. These were people’s opinions regarding mundane issues, like whether coffee is better than tea. A brain-imaging scan showed that when people received the opportunity to communicate their opinions to others, their brain’s reward centre was strongly activated.

We experience a burst of pleasure when we share our thoughts, and this drives us to communicate. It is a useful feature of our brain, because it ensures that knowledge, experience and ideas do not get buried with the person who first had them, and that as a society we benefit from the products of many minds.

Every day 80m new Instagram photos and 616m tweets are placed online

Of course, in order for that to happen, merely sharing is not enough. We need to cause a reaction – what Steve Jobs aptly referred to as making a “dent in the universe”. Each time we share our opinions and knowledge, it is with the intention of having an impact on others. Here’s the problem, though: we approach this task from inside our own heads. When attempting to create impact, we reflect on what is persuasive to us, our state of mind, our desires and our goals. But if we want to affect the behaviours and beliefs of the person in front of us, we need to understand what goes on inside their head.

What determines whether you affect the way others think and behave or are ignored? You may assume that numbers and statistics are what you need to change their point of view. As a scientist I certainly used to think so. Good data, coupled with logical thinking – that’s bound to change minds, right? So I set out to test whether information alters people’s beliefs. My colleagues and I conducted dozens of experiments to figure out what causes people to change their decisions, update their beliefs and rewrite their memories. We peered into people’s brains, recorded bodily responses, and documented behaviour.

Well, you can imagine my dismay when I discovered that all these experiments pointed to the reality that people are not driven by facts. They are not enough to alter beliefs, and they are practically useless for motivating action. Consider climate change: there are mountains of data indicating that humans play a role in warming the globe, yet approximately 50% of the world’s population doesn’t believe it. What about health? Hundreds of studies demonstrate that exercise is good for you and people believe this to be so, yet this knowledge fails miserably at getting many to step on a treadmill.

The problem with an approach that prioritises information is that it ignores the core of what makes us human: our motives, our fears, our hopes, our desires, our prior beliefs. In fact, the tsunami of information we are receiving today can make us even less sensitive to data because we’ve become accustomed to finding support for absolutely anything we want to believe with a simple click of the mouse. Instead, our desires are what shape our beliefs; our need for agency, our craving to be right, a longing to feel part of a group. It is those motivations we need to tap into to make a change, whether within ourselves or in others.

The Influential Mind by Tali Sharot is published by Little, Brown on 31 August, £18.99. Order it for £16.14 at bookshop.theguardian.com