We’ve all had the experience of mixing up left and right, often when trying to explain a route to a driver when we’re feeling under pressure ourselves. Confusing left and right may have been a contributing factor to the rout of Sir John Cope’s Hanoverian forces at the Battle of Prestonpans in 1745. In his analysis of the battle in the 19th century General Cadell, thought Lascelles might have confused left and right when issuing his orders to his unit. The result was the troops were facing wrong way to fire on the closing Jacobite forces. Mistakes made under pressure, or when several things are happening at once, reflect what is now commonly thought of as a problem of cognitive loading. By relying on compass-based directions, rather than left and right, we can act with more confidence and let the compass do some of the thinking for us.
As a geologist, mapping rocks requires us to be able to describe clearly the direction and angle of dipping rock strata, as well as location (gird reference) where the measurement is taken. While a number of conventions exist, left and right would be a poor choice, as such a system would rely on other geologists going to the same site and standing in the same place to understand the orientation of the rocks. Topographic and geological maps use the frame of reference of the map grid to allow us to understand the terrain or the geological structures without needing to be there.
Left and right relate to ‘handedness’, literally for most humans and also for many other objects. The problem is that, although what the concept describes is real, it is described within a changing (relative) frame of reference. In navigation, this generally means relative to our own body. The easiest illustration of this is to stand up, stretch out your arms and pick an object to your left or right when facing in this direction. Now turn round to face the opposite direction. The object you picked will now be on the opposite side, as you have moved your relative frame of reference. The simple cartoon below illustrates the concept.
As we are released from lockdown, a good way to illustrate this to groups is to get them to face each other is pairs and give them a point to do this with. Compass directions do not carry this risk, as the magnetic field of the Earth is an external frame of reference. This is another reason why you should trust your compass: the one thing a compass needle does much better than you ever can is point to magnetic north.
Going back to the introduction, the examples I picked include another factor that is very relevant in outdoor situations. In both cases, the person had other things on their mind, what is referred to as cognitive loading, that interfered with processing left and right. If someone is trying to describe the route they took when getting misplaced, if they are saying right and left, there is more chance of an error, especially if they are not confident with their map. Some people, for a range of reasons, may also have difficulty processing all of the elements required to determine left and right, as this article explains.
Newcomers to navigation can be helped by introducing the map and compass at the same time and by bringing in the compass, we can offer them a clear way to communicate information to teammates and supervisors/leaders. An extra benefit of doing this is that route cards can be written using cardinal (N, E, S, W) and intercardinal (NE, SE, SW, NW) points, rather than left and right. Which should minimise all the problem of people confusing left and right at crossroads, or becoming misplaced if they walk into the right junction from the wrong direction. Even the very cheapest of compasses will not be confused by this problem.
By removing left and right from our own use and stripping compasses back to their most basic function, a needle that points to magnetic north, we can give participants enough skill and vocabulary to be effective navigators on path networks by removing a number of potential problems bound up with ‘knowing your left from your right.’