Eddie Dekel points out the following puzzling fact. At the gym most people wipe down the exercise machines and benches after they use them and not before. There are a few obvious social benefits of this policy. For one, you know better than your successor where the towel is most advantageously deployed. Also, the sooner that stuff is removed, the better.
But still it’s a puzzle from the point of view of dynamic efficiency. With this system everyone mops once. But there exists a welfare improving re-allocation where one guy doesn’t mop and after him everyone mops before using the machine. Nobody’s worse off and that one guy is better off. A Pareto improvement.
In fact the ex-post-mop regime is especially unstable because that one guy has a private incentive to trigger the re-allocation. He’s the one who saves effort. So from an abstract point of view this is indeed a puzzle. Moreover, there is this Seinfeldian insight that complicates things even further.
ELAINE: Never mind that, look at the signal I just got.
GEORGE: Signal? What signal?
ELAINE: Lookit. He knew I was gonna use the machine next, he didn’t wipe his sweat off. That’s a gesture of intimacy.
GEORGE: I’ll tell you what that is – that’s a violation of club rules. Now I got him! And you’re my witness!
ELAINE: Listen, George! Listen! He knew what he was doing, this was a signal.
GEORGE: A guy leaves a puddle of sweat, that’s a signal?
ELAINE: Yeah! It’s a social thing.
GEORGE: What if he left you a used Kleenex, what’s that, a valentine?
(conversations with Asher, Ron, Juuso and Eddie. I take all the blame.)
Cheap Talk 
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February 7, 2010 at 10:34 pm
Debasis
I guess things will change if every agent assigns a value for cleaning his own sweat (and getting noticed of cleaning your own sweat).
February 7, 2010 at 11:58 pm
wheninrome15
A lady in my building recently sent out an irate email noting that some people weren’t cleaning the lint filters in the dryers after doing their laundry. I had the same thought.
February 8, 2010 at 1:13 am
Mario
I would think that the problem with pre-mopping is that you would be carrying around a towel covered in someone else’s sweat, which would actually defeat the purpose of wiping if you also intend to use the towel on yourself. I wouldn’t know, though; I don’t frequent gyms.
February 8, 2010 at 8:36 am
jeff
at the gym in question there are dedicated towels at each station, so that’s a good point but it doesn’t apply at least to this gym.
February 8, 2010 at 2:13 am
Kevin Dick
I am a gym rat and Mario has hit the nail on the head. Most gym patrons prefer to be in contact with other patron’s bodily exudates as little as possible. If you switch to pre-mopping, then everyone has to carry two towels and remember which is for mopping equipment and which is for mopping yourself.
February 8, 2010 at 6:27 am
shrik
Also explained by the common human tendency to prefer cleaning up their own mess as opposed to others’.
February 8, 2010 at 7:43 am
William
At my campus gym everyone uses paper towels to clean the exercise equipment, so Mario’s point doesn’t apply. Everyone still cleans the machines afterwards. It applies even when, at the end of the day, the staff are obviously hovering ready to clean the machines properly (and since they clean the places nobody ever cleans after themselves, like the edges of the belt on the treadmills and the footplates on the elliptical machines, cleaning before them is clearly pointless).
The puzzle is not why this equilibrium can be supported (it doesn’t take much staring to make me want to clean the machine, so we don’t even need dynamic punishment strategies), but whether there are any gyms where the other equilibrium applies.
February 8, 2010 at 10:25 am
Sean
As has already been mentioned, most people would strictly prefer to wipe their own sweat than someone else’s. Further, when you wipe before you use equipment, you are protecting yourself (from germs), when you wipe afterward you are protecting others. Signaling altruism in the gym may have dynamic and psychological benefits, as the gym can be a place where cooperation is important (e.g., sharing equipment with strangers through alternating sets) and anxiety is high (I suspect most people are self-conscious of their relative physical standing since it is observable, so wiping after yourself may be analogous to a dog rolling over for an alpha dog; most people are trying to be as small a presence as possible).
As to William’s point about gyms where the “wipe after” convention does not apply, I strongly suspect the less crowded the gym, the more likely people wipe after rather than before, due to the increased likelihood of shirking and the diminished benefits to signaling altruism. Related to the finding that men are less likely to wash their hands when alone in a restroom than when others are present.
February 8, 2010 at 12:02 pm
Kevin Dick
@William. I bet that your observation applies only to cardio equipment. Given the amount of moving between equipment during strength training, using paper towels isn’t very feasible.
Of course, there’s a lot of overlap between strength and cardio populations so any equilibrium in strength training will serve as an anchor in cardio. Combine that with the cooperation signaling cited by Sean and you have a pretty strong tendency toward wipe after.
I’ve worked out in maybe 30 or 40 different gyms and I’ve never seen a wipe before equilibrium. I’ve seen individuals wipe before, but then they _also_ wipe after. As Sean points out, if there were an unbusy gym, you might see wipe before. But gyms probably go out of business if they can’t attract enough customers to make them fairly busy.
February 9, 2010 at 8:37 pm
Anonymous
Is there a last person?