Moral Foundations Theory is a social psychological theory intended to explain the origins of and variation in human moral reasoning. The theory proposes moral foundations such as fairness, care, in-group, authority, and purity, and has been popularized by psychologist Jonathan Haidt in his book The Righteous Mind.
Haidt describes human morality as it relates to politics and proposes differences between conservatives and liberals as they relate to the moral foundations (TED Talk). Specifically, whereas conservatives appeal to fairness, care, in-group, authority, and purity equally, liberals appeal to fairness and care more than they appeal to in-group, authority, and purity.
Setting out to observe this phenomenon within Reddit Political Communities, I performed word frequency analyses on the /r/Republican and /r/Democrats corpora, totaling the words for each moral foundation, as defined by the LIWC dictionary. Comparing the totals, I found a trend consistent with Moral Foundations Theory. The visualization shows the moral foundations for /r/Democrats normalized against those for /r/Republican, with each value for /r/Republican set at 100%.