Are the Republicans leading a dumbing down of Congress?

There is a new study of the complexity of speech used by members of Congress. The study looks at addresses to the Congress. Longer sentences and increases in multisyllabic word counts suggest that the language is more complex. Complexity is scaled according to the grade level of students that on the average would be required to fully understand the text.

The following chart shows that the complexity of language has decreased markedly in recent years:

Note that there was a precipitous drop in complexity of remarks by Republicans after the 2006 congressional election (that is in the Congressional sessions in 2007 and 2008). There was a further major decrease after the 2008 presidential election (i.e. in 2009 and 2010). The 2010 congressional election saw the Republican level of discourse remain about the same, but the Democrats's remarks after that election also decreased in complexity. The Democrats made more complex remarks than the Republicans on average 2006, reversing a long standing pattern.

Note how the complexity depends on the ideology of the speaker, based on data since 1996.

As one would expect, Republicans (red) are more conservative than Democrats (blue). There does not seem to be any marked relationship among liberals between ideology and complexity of speech (Although the handful of Democrats with the least complex speech have the most liberal voting records in Congress). The more conservative the Republican, the simpler the language he/she used. Indeed, the simplest language used in the Congress was by the speakers with the very most conservative voting records.

The trend here is not in stump speeches, where it might be explained as an attempt to communicate better with the general public, who have an average of an 8th grade level of comprehension; this is is speeches on the floor of the Congress, presumably to fellow members. I would suggest that the complexity of speech in this context represents more the level of complexity of the speaker's thinking than of his/her conscious effort to communicate with his/her peers.

I find this data quite disturbing. There are serious political issues before the Congress and I would expect them to demand debate with sophisticated thinking expressed in elegant language. That clearly is not what is happening. Note too, would would hope that the people with the most extreme views in the Congress, who would have the greatest ideological distance to move their colleagues, would use the most complex and elegant language, where quite the opposite seems to emerge from the data.