occasionally on this site, i try to provide some background on phrases and cliches in social science and global health (such as here and here). it is a small public service to help folks not be sicilians yelling “inconceivable!” (or from starting land wars in asia, if at all possible).
today, the john henry effect.
the john henry effect is a reactive effect we could find in the comparison group of an experiment (or an any non-intervention group) when the comparison group is aware it is not receiving treatment. with this knowledge, they might react by working harder to compensate for not having the intervention. the effect, apparently, also includes the reaction amongst the ‘non-treated’ of becoming discouraged at not having received the intervention and working less hard, though i am less familiar with this usage. in any case, we could just call them ‘reactive effects’ and given all the other cultural roles and meanings of john henry, i wonder if we just should.
the point of this post is not about the john henry effect but about john henry. however, a small point. david mckenzie‘s post on the john henry effect (and that we shouldn’t be too worried about it) concludes “often our best approach may be to try and reduce the likelihood of such effects in the first place – while it can be hard (or impossible) to hide from the treatment group the fact they are getting a treatment, in many cases the control group need not know they are controls.”
this seems at odds with mckenzie’s seeming support in other places for public randomization (example here)– in which case, the comparison group would very well know that they were not receiving the treatment. (the problem, in part, is that we have limited scope in the way of placebos in social science work. ethics aside, we simply don’t know how to give you a malaria-bednet-that-isn’t-really-protective in the way that i can give you a lookalike pill that has no active pharmaceutical ingredients. which is, perhaps, another argument for testing treatment variants against each other rather than treatment against just ‘business as usual’/nothing new.)
in any case, the real point of this post is about john henry the man/myth. from a recent conversation with a colleague, it was clear that, for him/her, the john henry effect could have just as easily been named for the researcher that discovered the effect or the site at which it was first noted (as in the hawthorne experiments).
which is fair enough. john henry is an element of americana folklore (though there may well be counterpart or antecedent stories in different cultures and i would be delighted to hear about them), so why should anyone else be clued in?
however, i had to sing a song about john henry in 5th grade choir performance about american tall tales (quite possibly the last time i was permitted to sing on stage), so i am fully qualified to provide some background on john henry.
it seems (mostly according to here and here) that john henry was likely a real man — definitely black, possibly born a slave. he worked for the railroads following the civil war (in the late 1860s and 1870s). he was well-suited to this work, as a “steel driving man”, as he was, from existing accounts, both quite tall and muscular. most accounts say he worked for the C&O Railroad (chesapeake & ohio) and many accounts put his work as drilling through the big bend mountain in west virgina, where it was decided it was more expedient to make a tunnel rather than go around the mountain (alternatively, he worked on the nearby lewis tunnel under similar circumstances).
“as the story goes, john henry was the strongest, fastest, most powerful man working on the rails. he used a 14-pound hammer to drill 10 to 20 feet in a 12-hour day – the best of any man on the rails. one day, a salesman came to camp, boasting that his steam-powered machine could outdrill any man. a race was set: man against machine. john henry won, the legend says, driving 14 feet to the drill’s nine. he died shortly after, some say from exhaustion, some say from a stroke.”
another account, by an alleged eyewitness account collected by sociologist guy johnson in the 1920s, is:
“when the agent for the steam drill company brought the drill here, john henry wanted to drive against it. he took a lot of pride in his work and he hated to see a machine take the work of men like him. well, they decided to hold a test to get an idea of how practical the steam drill was. the test went on all day and part of the next day. john henry won. he wouldn’t rest enough, and he overdid. he took sick and died soon after that.”
john henry became the subject of ballads and work/hammer songs (e.g. and here and here) and an important touchstone for the american labor movements and civil rights movements. he is a lot more than a possible effect in social experiments!
as a closing thought, when we discuss john henry effects, we mostly think about his working hard in compensation for not having the treatment (a machine) — or even proving that the treatment was unnecessary because of pride in the status quo. we think less about the fact that he died from it. given this part of the story, we may want to consider, should we find john henry effects, not just that it might mess up our effect estimation — but that harms could be coming to groups not receiving interventions if they are over-compensating in this way (more akin to how john henryism and soujourner truthism are used in sociology and health psychology (e.g. here and here) to describe the african-american experience and weathering).