If you have ever had the misfortune of getting lost in a crowded city, you are no doubt already acquainted with a surprising and little publicized fact: The greater the number of people who might potentially be asked for directions, the more difficult it becomes to get someone to actually stop and help.

Scientists who study human behavior call it the Who, Me? syndrome. For example, if you should have the truly awful luck to get a sliver of sparerib stuck in your throat while dining alone in a restaurant in which there is only one other customer, your fellow diner, although a total stranger, will almost certainly leap up and start performing the Heimlich maneuver as soon as you make the universal sign for choking. (If in doubt as to what this sign is, please refer to the informative poster on display in the dining area; this is assuming you are still conscious, of course.)

Whereas, if the same incident takes place in a bustling restaurant full of people, by the time you draw attention to your plight you may have already turned blue and fallen to the floor. At that point you are truly in a pickle, for instead of swift action there will be a lengthy discussion as onlookers try to determine which of them is best qualified to assist. Some will suggest mouth-to-mouth resuscitation, while others will strive to recall episodes of medical television dramas that may or may not be relevant to your case. A few will phone for help; others will panic and require medical assistance themselves; and many, alas, will simply be annoyed that their dinner was interrupted and will tip their waiters ungenerously as a result.

Knowing this, in the future you might well choose only to dine in unpopular restaurants. Penelope did not have this option. London was crowded, and there was no getting away from it. Each new street she trudged down with her three weary charges in tow seemed more packed with unhelpful people than the one before. After an hour's aimless wandering she knew that she and the Incorrigibles were lost, but all her attempts to ask for directions went unanswered in the din and rush of the crowd.