By simple observation, it is possible to mark out certain patterns of human behaviour. Often, they are interwoven with each other in a very sophisticated way. Most patterns of human behaviour and interaction depend on cultural background or social adjustment.

There are some though that transcend geographical, ethnic or religious boundaries. Like social interactions in a bus, for example.

Get in and pick a seat

Every week or so, I happen to end up an eyewitness to or a partaker of some strange situations despite my rather monotonous and quotidian schedule. All cases I am referring to have to do with relationships and interactions.

The relationship with my landlord, for example, is the utter example of an interaction water boiling over the edge. I seem to never be able to guess what services his company is to pay for and what expenses I am to cover. The most disappointing problem is that he seems always to assume I have to guess the exact very thing.

Although, strangely enough, more frustrating to me are the social interactions that occur in the public transportation vehicles. Buses, trams, trolleybuses or trains – you know, the ones with usually unequal ratio of seats to passengers.

One of my most favourite things to do while on a bus (which is a curious thing in itself) is observing people. I am always amazed at how you can make out the silent unspoken social interactions among commuters deciding which seat to take. Some people, I have noticed, make the important decision of selecting a seat randomly, without any thought put into the action.

Most people, though, do it as if they were guided by some kind of force so strong that the mere immensity of it all takes my breath away. After a while, I have been able to decode the source code and have an almost perfect score at guessing which seat the newly embarked passenger would take (provided the person even unknowingly is following the observed patterns).

These patterns reminded me of many forms of social etiquette. Before long, the idea of the need of setting up and publishing some principles of a socially optimal seat selection in the public transportation dawned on me. Now, the current principles are by no means exhaustive or complete. Nevertheless, I have tried my best to include most combinations in the list.

Without further ceremonial ado, I present to you:

Principles of Social
Optimality

In the examples below, there are four types of seats, each marked by its colour. An occupied seat (black) is already taken, so you have to look for another one. A free unoccupied (white) seat, a warning seat (purple) seat and your best choice seat (teal) are all empty and free to take. Aim at the best choice, for such seat is as socially optimal a seat as you can get!

The present principles are not to be regarded as rules, let alone laws, but rather as guidelines only. They are free to love or hate, as well as republish, reuse and modify. Link, however, to this article if you do. Please.

Basic principle. The father of all principles

If there are unoccupied seats available, take one. Never stand while in a public transportation vehicle. Because it is lame. Because you take public transport for convenience and it means you get a seat. Because if you think sitting down makes you fat, you should have taken a walk in the first place. So, once again, if there is a seat available, take it.

Principle 1: The principle of adjacency

Never take a seat adjacent to the one already occupied. Thus you avoid the awkward intrusion caused by stepping over the boundaries of your fellow commuter’s privacy according to the private space axiom.

In the example to the left, there are two pairs of seats separated by an aisle. Your best choice is obviously to take the seat belonging to the pair across the one already containing a taken seat.

The glossary of this and similarly clever terms can be found at the end of this article.

Principle 2: The principle of an aisle and a driver

If at least one seat on all pairs of seats in a transverse row is occupied, take a seat closest to the driver in the longitudinal row closest to the aisle.

Longi-what row? Tudinal. Longi-tudinal. There are long rows of seats that go lengthwise (longitudinal) and short rows of seats that go crosswise (transverse). To make it easier to understand, think airplanes. Transverse rows are usually numbered 1, 2, 3, etc. and longitudinal rows are usually marked with a letter A, B, C, etc. Take a look at the glossary.

So, this one is a bit trickier, isn't it? Not to worry, though. It is not that complicated. The example to the left shows that the most optimal choice is the free seat closest to the aisle. This aisle aspect of this principle does not let you take any of the two free seats by the window. The driver aspect, in its turn, does not let you take the other aisle-near seat.

Though the location of the aisle may be apparent in the example, that of the driver's seat can be harder to detect. Keep in mind, therefore, that the relevant examples feature seats against the driving direction.

Principle 3: The chessboard principle

If two non-adjacent seats in a transverse row are occupied and there is one unoccupied transverse row behind or in front of the given row, take a seat across any of the occupied seats (i.e. not directly behind or in front of them), thus forming a kind of a chessboard.

This principle implies alternating seats as to both longitudinal and transverse rows simultaneously, so that the common chessboard is formed. The principle may go by another name, too – The diagonal seating principle. The example to the left shows that choosing a seat right behind (and in front) of the one already occupied is less socially optimal than choosing an adjacent seat.

Principlet 3: The back-to-back chessboard principlet

If there is only one seat occupied in a quartet of seats, the chessboard principle is still valid, provided there are no other unoccupied pairs of seats, in which case the fourth principle – The principle of an empty row – should be followed.

This baby principle ("principlet") take into consideration the driving direction due to the nature of the quartet of seats. This principlet is also valid when seats in two transverse rows are placed "face-to-face".

Principle 4: The empty row principle

If two non-adjacent seats in a transverse row are occupied and there are two or more unoccupied transverse rows behind or in front of the given row, take either empty seat one row in front of the given row, leaving out one row (behind you) empty, following the chessboard principle in relation to the occupied seats in the nearest transverse row (the one in front).

The example to the left shows expressely that the best choice is to leave an empty row behind you, thus making it possible for other commuters to enjoy the social optimality by keeping their private space adequately untouched.

The empty row principle does not, obviously, eradicate any of the above-mentioned principles, if, for instance, two or more transverse rows are unoccupied. Instead, each successive principle complements the ones before.

Principle 5: The side-by-side row principle

If there is only one unoccupied seat between two occupied seats, take it. Why? Because you have not been paying attention. Now, let us take the examples one by one.

If all seats in the row are unoccupied, take one of the end seats, preferably the one closest to the aisle or exit.
NB! If one of them is already occupied, take the other one, even if it is not closest to the aisle or exit.
If there are two unoccupied seats between two occupied seats, take one of the unoccupied seats which is closest to the aisle or exit.
If there are three or more unoccupied seats (odd in number) between two occupied seats, take the middlemost unoccupied seat in-between.
If there are four or more unoccupied seats (even in number) between two occupied seats, take one of the two middlemost unoccupied seats in-between, preferably the one closest to the aisle or exit.

Get inspired (to extend the principles)

As already mentioned in the Background section of this article, the list of principles is in no way a complete or comprehensive one. There are many combinations out there that need special attention. The present list can, however, be used without limit as a personal guide.

Yes, it is true, all current principles assume you are a solitary traveller. Not a lone voyager, are you? Well, if you are followed by a company of one other commuter, most of the present principles still apply, but may vary depending on the relationship between the two of you. As they do when you are riding the public transportation vehicle in a group of three or more passengers.

Though it is crucial to know the guidelines for picking the most socially optimal seat, the present principles do not only apply to public transportation. Banquets at restaurants with many different table settings or waiting rooms at the hospitals, clinics or care centres are but a couple of examples of extended usage of these (or similar) principles of social optimality.

The sources that I drew inspiration for the article from are to be enjoyed profusely:

Randall Munroe's comics on movie seating, seat selection and optimal moves.
Z-Studios' mocumentary based on ApoxyButt's write-up on "Male restroom etiquette"
Paddy Donnelly's bus game and philosophy on doodling

Glossary

Private space axiom: the self-evident truth of the holiness of one’s private space
Transverse row: any one of rows of seats going crosswise
Longitudinal row: any one of (usually four) rows of seats going lengthwise
Pair of seats: two adjacent seats
Quartet of seats: two pairs of seats placed back-to-back

Bon voyage!