Probabilistic Alarm Clock

Last weekend’s FT had a Dear Economist (i.e. Dear Tim Harford letter) from someone who always sets his watch fast and still manages to fool himself into being on time. ‘Mark’ wondered how this was possible, what with him being a rational actor who writes to economists asking for life hacks.

The answer was “you have a split personality, a warped view of time and are too lazy to do simple sums. Now put down this magazine: I suspect you are running late for something.”

This has occurred to me too, for years. One solution, have a significant other set the clock for you, some random amount of time between 5 and 15 minutes fast. Or, you can close your eyes, and try to do it yourself.

It’s still difficult because of the number of clocks around you at any time (your computer, television, in your car, etc).

My reaction was the same as that of abb1. Is there something wrong with that logic?

4: But that will sometimes make you late: knowing this is your incentive to always believe the clock, just in case.

Watches are a confidence trick invented by the Swiss.

I used to do this self defeating trick and now I use it in the classroom as an illustration of how a monetary expansion in the presence of money illusion can give a boost to the economy in the short run but just leads to more inflation and price signal confusion in the long run.

Say you set your alarm clock ahead 10 minutes right before you go to bed (money supply up). Next morning you wake up and being dozy you fail to remember that the time is wrong – so you get up 10 minutes earlier (output up). Next morning however, having had the experience once before, you wake up, take a look at that clock and say to yourself “that thing is 10 mins too fast” and go back to sleep (inflation up, output back down). What to do? Well, you could set it ahead by another 10 mins (or whatever – just pick a new point on the now shifted Phillips Curve). It works for another morning, but the day after that you wake up thinking “wait, is the clock now 10 mins fast, or 20 or 30? Did I reset it again? What is the freakin’ time????”

Making it probabilistic is just the application of the Lucas principle that in order for monetary policy to be effective the monetary authority has to constantly surprise people in the economy else they will incorporate its behavior into their expectations (“that clock is 10 mins fast”) and the policy will have no real effects. But of course, “randomness” is no way to conduct a good monetary policy, and likewise it probably isn’t a good strategy for waking up in the morning.

Which is why now instead I just have my girlfriend call me a couple of times in the morning, in addition to the alarm clock. You can turn the alarm clock off but if I don’t answer the phone I’ll be in the doghouse. Maybe this is like a credible committment to a monetary rule.

And people on here were arguing that the Rational Expectations Hypothesis doesn’t hold!!!

I always wondered if I was rational, or even half way rational, and now I know: according to the experts, I am not. (I use the trick and do not correct, or, more exactly, do not correct until I am out of bed.)

No, your clock is not +- 10 minutes, it’s always ahead, it’s ahead by between 5 and 15 minutes and you know it.

I don’t think that matters. Let’s say the meeting is at time m and whatever time you try to arrive at (a) you will end up arriving at a+r, where r is in the range -5 to 5 (because your estimate of the time may be out by +/- 5 minutes). You will not (rationally) set a to m, because the penalty for being late is larger than the penalty for being early. Depending on the relative size of these penalties you will set a to some number less than m, possibly to m-5.

Then again, if you were rational, you’d just leave on time in the first place.

11. “Which is why now instead I just have my girlfriend call me a couple of times in the morning, in addition to the alarm clock.”

– which is fine as long as your girlfriend does not suffer from the same problem. But then, I guess you could call her.

I love you, Henry.

The proliferation of nearly perfect timepieces (mobile phones being the handiest example) is obsolescing this strategy.

I’ll note my preference at the outset: I have two radio-controlled clocks, a clock radio and a watch; my computer contacts the NIST timeserver daily; the landline phones get the time via caller ID; the cable tuner’s time is set remotely. (The thermostats, ovens, coffee maker and sundry other timepieces are manually adjusted and undependable, and yes, changing to and from daylight savings time is a major festival in my household.)

In my experience, people who try to compensate for running late by fooling themselves continue to run late, probably because it’s hard to forget that you’re lying to yourself.

For a commuter, an alarm connected to the net and tracking traffic delays could conceivably be useful, but the option of an additional aleatory uncertainty would not.

Surely a rational actor is only late for meetings that they don’t really care much about being late for, at least thats how it works for me, so having unreliable time pieces would just act as an excuse for being late (I certainly know some people who use to deliberately have their watch running several minutes late so they can ‘correct’ it when they arrive a few minutes late for a meeting, this would seem to be able to be used for the same purpose).

Anyway, all users of South West Trains have a similar but opposite system – we get up at the same time in the morning but the trains are delayed by a random number of minutes between zero and 30.