I guess this happens to most of us who get to ride in elevators atleast twice a day. Its a statistical problem and no one seems to understand it and it is always a battle between being nice and doing the right thing. If I get into an elevator to reach the 4th floor (my company has only 4 floors), I would like to have the least amount of people travelling with me. The more people there are in the elevator, the more probability that it should stop at more than 1 floor. So, when the elevator is about to take off, and there is someone coming towards the elevator from a distance, I usually dont care about stopping to pick them up. It is not just the waiting time for them to get into the elevator, but, there is also an additional 2/3 probability for them to get into one of the other floors than the one where I am heading. Consider the plight when the number of floors become too large. The ride time in the elevator grows with every new passenger. If there are fewer elevators, then you dont have a choice, especially in very high rised buildings. But, if there are ample elevators, why not just go ahead without waiting for the other person to join. Its going to be what, a few seconds before they get their next ride. One could argue that I would have the same impact admitting them. But then, the window of new comers to elevator increases, which invariably would end up with me having to wait for some more. I have consistently seen people displaying a major act of kindness and caring when it comes to picking one more person up on the elevator. I just dont understand it.
If the above paragraph is about going up the elevator, this is about coming down. The same statistical theory applies here as well. On top of it, there is a new problem now. In my office, on the exit path from the elevators, there are 2 hard glass doors and they are quite difficult to open on a windy day. One has to come out of the elevator and the first door leads to the lobby and the second door leads you out of the building. When I travel alone on the elevator, things are just normal.. so to say. Whenever I have someone else travelling with me, I always end up with this big confusion, which I havent resolved yet. When the elevator stops and dings you to get out of it, I wonder if I should be the person to exit first or let the other person out. If I get out first, it might seem a little rude at the beginning, but then, I end up opening the other 2 doors for the other person(s) and bag myself with a couple of “thank you”s. If I wait and let the other person go, then, they have to do the same to me and I will be obliged to say couple of half-hearted and half-pronounced “thank you”s. My challenge lies in looking at the person and deciding quickly if I am going to go first or let them go out first. Sometimes, though I decide to go first, especially, if the other person looks a little weak, the other person gets out first, sort of forcibly. I smile to myself and then wait for them to open the doors for me…:)… Interestingly enough, in both cases, if the other person is hot, it somehow seems to override all the rules of rationality and only caring and kindness remain…
PS: For those of you interested in the math behind the observation:
Time Risk (to reach floor n at floor 0) = Start Time + (P1+P2+….PJ)*((n-1)/n)*(UL_TIME) + (P1+P2+…PJ-1)*(n-2)/(n-1)*(UL_TIME) + …..+ (P1+P2…PJ-n-1)*(UL_TIME)
(Not adding any wait-times to show caring and kindness)
UL_TIME = Unload and Load Time, J=number of passengers, n = number of floors to travel