Cognition in Aviation — Page 185, Lesson 297

I want to walk you through the start of the chapter on cognition in aviation. This is a critical topic because it explains why your own brain can become your biggest threat in the cockpit. Let's begin with the introduction. Human beings evolved to function at sea level and at speeds achievable on two legs. That means our senses and our brain are calibrated for walking around on the ground, not for being in an aircraft. Flight puts the pilot into an environment which can distort sense organs. On top of that, the changed perspective you experience in flight can result in information being presented which is outside the individual's expectations. In other words, what you see or feel may not match what your brain expects to see or feel. Now, let's talk about illusions in general. We use mental models as frameworks to make sense of the world and guide our actions. A mental model is essentially your brain's internal prediction of how things should behave based on past experience. The problem is that mental models can be incomplete and thus faulty. In aviation, the mismatch between what we sense and what we expect is called an illusion. Put another way, it is the difference between perception and reality. Perception is what your brain interprets from sensory input; reality is what is actually there. When those two don't match, you have an illusion. Objects seen from the air look quite different than when viewed on the ground. Because of the lack of stable visual references and the erroneous mental models that may be produced, the pilot is at a disadvantage. In addition, in flight, the pilot's cognitive and sensory orientation mechanisms have to try and cope with a third dimension to which they have not been designed. Your brain evolved for a two-dimensional surface world; now it has to handle height, pitch, roll, and yaw. This will lead to both mental and physical illusions. Illusions may occur during all stages of the flight and to pilots of every experience and skill level. That is an important point: even a very experienced captain is not immune. The pilot, therefore, should be aware of the possibility of misinterpreting the information received. Illusions can affect all of our senses, but those of particular concern in aviation are those which affect our visual sense and those affecting the balance organs in the middle ear. We also possess a position sensing system derived from nerve endings in the skin, muscles and joints which can be a source of incorrect information passed to the brain. That is your proprioceptive system, and it can also lie to you. Visual illusions are particularly dangerous in aviation as we normally consider our visual input to be the most reliable of our senses. That trust makes them especially insidious. Now let's move into the section on visual illusions. Most people are familiar with two-dimensional geometrical illusions. Let me walk you through the examples in Figure 10.1. In example A, the figure with the outward-pointing fins appears to contain a longer line than the other, although both are exactly the same length. This is the classic Müller-Lyer illusion. We are not often going to see large finned lines on our airfields, but the natural scenery — the junction of two roads or railways, the alignment of valleys, even a small runway running into the corner of a field where hedges meet — can give a false impression of runway length. So if you see a runway that looks longer than it actually is because of converging lines at its end, you might misjudge your approach. In example B, the upper of the two horizontal lines appears the longer, but they are the same size. This is the horizontal-vertical illusion. In example C, the vertical straight lines appear curved, but they are straight. That is the Zöllner illusion, where intersecting oblique lines make parallel lines look bent. In example D, the question is: which line passes through the two vertical parallel lines? The excerpt suggests you try it with a straight edge. The point is that your eye can be fooled by the surrounding pattern. Other visual illusions involve a perceived depth appreciation. Both of the illustrations in Figure 10.2 and Figure 10.3 can obviously be visualised as a model, but neither could exist in real life. These are impossible objects — your brain tries to interpret a two-dimensional drawing as a three-dimensional scene, but the geometry doesn't add up. The key takeaway here is that your visual system is not a perfect camera. It interprets, it guesses, and it can be wrong. In the air, those wrong guesses can kill you. That is why we study these illusions — so you can recognise when your brain is lying to you and rely on your instruments instead.