Could you watch my bag?
You are sitting in a cushy chair at your local library, reading a novel. As you flip the pages, drowning out the conversations surrounding you with the silent power of the written word, you are interrupted.
“Could you please look after my stuff? I’ll only be gone for a second.”
You unhesitatingly accept this proposition with a smile. After all, this is far from an uncommon request, and regardless you have no plans of leaving your comfortable chair anytime before the stranger’s metaphorical second has elapsed.
But why ask a total stranger to protect things from other total strangers? It seems counterintuitive, at the very least, to trust another person with belongings valuable enough to be stolen by an untrustworthy passerby.
The reasons behind such a request are undoubtedly irrational. People always want to feel as if their things are protected. In this sense, requesting a stranger to look after one’s belongings is similar to locking the front door; if a burglar wanted to break-in to a property, a locked door would be unlikely to impede them from doing so. Arguably, people lock their doors for peace of mind.
While people’s motivations for making such a request are irrational, I contend that the request itself is a rational one. That is, asking a complete stranger to mind your things is an effective way of reducing the probability of theft.
Take P to be the probability that any individual stranger will steal abandoned valuables. In most parts of the world, P is quite low. However, the overall probability of theft increases as more and more strangers encounter the valuables.
For example, take P=0.01, that is to say that every passing stranger has a 1% chance of stealing the valuables. Alternatively, 1 out of every 100 people will steal valuables when given the opportunity to do so. After 68 people pass by, there is about a 50% chance that the valuables have been stolen.
Now, let’s assume that asking one stranger to look after the valuables decreases the probability of theft to P. In other words, unless the stranger themself is predisposed to stealing the valuables, their watchful eye will prevent any theft from occurring. Thus, after the same 68 people pass by, the probability of theft is still only 1% as opposed to 50%.
Note that this model does not assume the chosen supervisor to be any more trustworthy than the average stranger. It follows that asking someone to look over your possessions in a public place is in fact a strategic move which greatly reduces the probability of your things being stolen.
There is probably something profound to be said here about irrational reasoning leading to logically-sound results, but it is time for you to get back to your novel.
