In 1970, Romney's mother ran for the US Senate, and he joined her on the campaign trail during his summer break. In the clip from the Bentley Historical Library, Mitt Romney describes his mother, Lenore,
So many of our Senators sometimes become so caught up in the political situation that their answer is made politically before the issue is even brought up. But she isn't so aligned to a political ideology, or a political side of the spectrum, that she can't analyze a situation, and vote in it and work in it completely candidly.
The clip can be seen online as part of the New York Times retrospective video piece, 2:30 mark.
While in 1970 Romney is describing his mother's decision making-process, he is also describing his own. This is Romney's strength and it is demonstrated by his extremely thorough, analytical approach to problem-solving.
Interestingly, a more empirically-minded and expansive approach, which in Romney's case manifests in conservative positions, is less vulnerable to irrational decision-making and more able to absorb concrete fact and logical theory.