The history of 'habit'

The new Google N-grams facility allows searching their huge digitized text collection for relative frequencies of terms.  Below is a plot for three concepts that come up often in this blog: 'habit' (blue), 'choice' (red) and 'decision' (green), shown from 1840-2000.  (A pretty amazing resource !)

Data from all English books, 1840-2000, computed 2010.12.17.

For many decades the three terms track each other at around .0035 percent of all items. They begin diverging sharply in the late 1920s, with 'habit' declining steadily from its peak in 1929. 'Decision' rises gently, and then quite sharply beginning in World War II. By 1980 it is at nearly ten times the level of 'habit'. 1929 is also the year in which 'choice' first becomes more frequent than 'habit', and it rises steadily from that point onward.

The data match up quite well with the claim that ideas of habit have been disappearing from our ways of thinking about the sources of action. (As in the Camic 1986 article, "The Matter of Habit".) In the 1920s Dewey could write that "habit is the mainspring of action" without seeming a little odd (in The Public and its Problems). Although our current era has many similarities to the "confused publics" he analyzed, we don't seem to have available for our reflections the  notion of habit as a fundamental human faculty that was an established resource in his time.