Internal Choices Are Weaker Than Those Dictated By The Outside World

http://www.sciencedaily.com/releases/2009/02/090211094036.htm

ScienceDaily (Feb. 16, 2009) — 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 implication is that, despite our feelings of being in control, our own internal choices are flexible compared to those driven by external stimuli, such as a braking in response to a traffic light. This flexibility might be important - in a dynamic world, we need to be able to change our plans when necessary."
...
"We often think about our own internal decisions as having the strength of conviction, but our results suggest that the brain is smart enough to make us flexible about what we want. The ability to flexibly adjust our decisions about what we do in the current situation is a major component of intelligence, and has a clear survival value."