Where have all the erections gone?

Solution 1:

Tom22 should get credit for this answer. I read his comment awhile ago, but he sounded dismissive of the idea that aroused might be picking up the slack. After just now doing several more comparative graphs, I see that he may well have been onto something.

access interactive graph

I thought about including "woody" from Martin Smith's graph. My searches, however, indicate that it is relatively rarely used in a sexual sense. Most results relate to wood itself, or the male name (eg. Woody Harrelson).

• arousal: not significant until around 1950 when it began a significant rise. It began tapering down around 1983, but still maintains more than 2/3 of its peak in 1983.
• arouse: steady, slow decline during most of the 1900s, with a very recent and small up-slope since about 2002
• aroused: huge decline since about 1936, with slight up-slope since about 2002
• erection: peak around 1876, followed by steady decline until 1997. It has been slowly ascending since then.
• hard on: enjoying a slow, almost steady rise since 1820

All the words except arousal have more general meanings. Even "hard on" is most often found in a non-sexual context. (eg, "She worked hard on her job.") Statistics without a known causality can be very misleading. Yet it seems compelling to me that we see the five words together suggest a coalesced sum total of the sexual connotation of erection. What erection, arouse, and aroused may have lost in any sexual connotation sure looks like it has been picked up by arousal. An exception is hard on, changing slowly and maybe gaining more sexual connotation over time, without losing any of the non-sexual usage. (Hardon and hard-on are statistically irrelevant.)