If morality is the answer to the question 'how ought we to live' at the individual level, politics can be seen as addressing the same question at the social level, though the political sphere raises additional problems and challenges. It is therefore unsurprising that evidence has been found of a relationship between attitudes in morality and politics. Moral foundations theory, authored by Jonathan Haidt and colleagues, has been used to study the differences between liberals and conservatives, in this regard. Haidt found that Americans who identified as liberals tended to value care and fairness higher than loyalty, respect and purity. Self-identified conservative Americans valued care and fairness less and the remaining three values more. Both groups gave care the highest over-all weighting, but conservatives valued fairness the lowest, whereas liberals valued purity the lowest. Haidt also hypothesizes that the origin of this division in the United States can be traced to geo-historical factors, with conservatism strongest in closely knit, ethnically homogenous communities, in contrast to port-cities, where the cultural mix is greater, thus requiring more liberalism.