We all like to think we have free will. It's comforting to know that every day we weigh up options (coffee or tea?), make a choice (coffee), and have some semblance of control over how our lives play out.

But new research suggests that our idea of 'conscience choice' might not play out like we think it does on the short-scale, and hints that free will might be nothing more than a cruel, cruel trick our brains play on us. In other words, we're not actually making decisions, we're just telling ourselves we did.

The new study was performed by neuroscientists from Yale University, and only applies to choices made over short periods of time (we're talking a few seconds here). But they found evidence that people aren't actually making split-second decisions before an action happens, even though they think they are.

Exactly how this happens still isn't understood, and right now this is all just a hypothesis that needs further testing, but the Yale team thinks it could revolutionise our concept of free will, if proven correct.

"Perhaps in the very moments that we experience a choice, our minds are rewriting history, fooling us into thinking that this choice - that was actually completed after its consequences were subconsciously perceived - was a choice that we had made all along," writes one of the researchers, Adam Bear, over at Scientific American.

They figured this out by performing experiments that tested how often people actually made a choice prior to an action. For example, in one of the studies, they asked 25 students to look at five white circles in random locations on a computer screen. They were told one of them was going to turn red, and were asked to quickly choose which one they though it would be.

If they didn't have enough time to make up their mind, they could indicate that, otherwise they simply answered "yes" or "no": "yes" if they had chosen the right circle, or "no" if they hadn't.

They did this over and over again, and, statistically speaking, they should have answered "yes" on average just 20 percent of the time.

But when the researchers analysed the results, they found that the students were reporting making the right choice way more often - more than 30 percent of the time when the circles turned red especially fast.

"This pattern of responding suggests that participants’ minds had sometimes swapped the order of events in conscious awareness, creating an illusion that a choice had preceded the colour change when, in fact, it was biased by it," writes Bear.

In other words, when the circles changed colour quickly, participants weren't actually choosing at all, but their brain was telling them that they had - and that what they'd seen was what they'd chosen. So their brain was working faster than they could process, leaving participants with the overwhelming feeling that they had chosen, when in reality they hadn't ever had the chance.

Interestingly, this only happened when the red circles appeared quickly - when participants had more time before the colour changed, the percentage of "yes" answers dropped back down to around 20 percent, hinting that, given enough time, students really were making a conscious choice.

"This result ensured that participants weren’t simply trying to deceive us (or themselves) about their prediction abilities or just liked reporting that they were correct," Bear added.

Of course this study has its limitations - it was a small sample size and the groups were self-reporting their choices, which is always problematic. Also, watching shapes change colour on a screen is a far cry from the day-to-day choices we make in our lives. But it's one of the first tests of an hypothesis that was first put forward by psychologists almost 20 years ago, and it's worth further investigation.

The big-picture question is why our brains would have evolved to do this. There's a chance that it doesn't actually happen in the real world, and our brains just aren't fast enough to process decisions without glitching in the space of time given in this experiment.

Or perhaps, Bear speculates, our brains tricking us into thinking we have free will might actually be beneficial - giving us the perception of control over our lives, and encouraging us to punish people for wrongdoing.

If that's the case, the research could have big implications for our understanding of mental health - where our feeling of control over our lives often goes awry.

"The kind of inconsequential choices that participants made in our studies bear little resemblance to the most important choices people make over the course of their lives," the researchers explain in Psychological Science.

"But everyday life is also made up of many less important decisions ... Perhaps, in these cases, our sense that we make a choice well in advance of our actions is an illusion, making us feel more in control of ourselves than we actually are."

Either way, the results suggest it's time to start rethinking some of our "ironclad" beliefs about free will.