The underlying sense of being in control of our own actions is challenged by new research from UCL (University College London) which demonstrates that the choices we make internally are weak and easily overridden compared to when we are told which choice to make.

The research, which is published in Cerebral Cortex, is one of the first neuroscientific studies to look at changing one's mind in situations where the initial decision was one's own 'free choice'. Free choices can be defined as actions occurring when external cues are largely absent - for example, deciding which dish to choose from a restaurant menu.

The researchers asked study participants to choose which of two buttons they would press in response to a subsequent signal, while their brain activity was recorded using EEG (electroencephalogram). Some choices were made freely by the volunteers and other choices were instructed by arrows on a screen in front of them. The volunteers' choices were occasionally interrupted by a symbol asking them to change their mind, after they had made their choice, but before they had actually pressed the button.

First author Stephen Fleming, UCL Institute of Neurology, said: "When people had chosen for themselves which action to make, we found that the brain activity involved in changing one's mind, or reprogramming these 'free' choices was weak, relative to reprogramming of choices that were dictated by an external stimulus…