Information Processing, Human Error and the Learning Process — Page 156, Lesson 246

I want to walk you through a critical concept in information processing: the danger of expectation. When you start hearing a familiar radio message, you tend to assume the end will contain the same information you've become used to. So you forecast or assume what's coming next, and your concentration tails off the further you get into the transmission. These kinds of assumptions have caused many an aircraft accident. Here's how it works in your mind. Information from your senses is compared to a mental model you hold, as part of your control process. If you detect a mismatch between what your senses tell you and what your model expects, then you have a problem to resolve. Often, instead of updating the model, we try to shape the data to fit the model — and errors occur. But when perception matches reality, you are situationally aware. An inherent danger in this system is that, having built a mental model, we tend to seek only information that confirms our model. That's called confirmation bias. We ignore other information that might cast doubt on the model's accuracy. A good example of confirmation bias is a pilot who is temporarily unsure of his or her position but hopes the aircraft is where it's meant to be. That pilot tries to fit the map to the ground. As discussed in Crew Resource Management, this loss of situational awareness is the time when leading questions start to appear — questions like "That was Witney, wasn't it?" This phenomenon tends to be brought on by stress. Now let's move to how we build three-dimensional models of the world. Our visual system has many cues to provide us with a three-dimensional model. These include: - Convergency — the amount that your eyes converge, or turn inward, to bring an object into focus onto each fovea, the central part of your retina. - Stereopsis — objects at close range provide a different picture on each retina than distant objects do, giving depth perception. - Obscuration — near objects occlude, or block, far objects. - Atmospheric Perspective — objects at a distance lose their colour and clarity. - Retinal Size — the angle subtended at the retina becomes smaller with increasing distance. Retinal size is of particular importance to you as a pilot. For example, in the final stages of an approach, you are likely to judge your height above the ground from the retinal size of the runway. To make this judgement, however, you must have a stored expectation of the likely size of the runway. If the runway is wider or narrower than you expect it to be, you may overestimate or underestimate your height. Let's now turn to short-term memory, also called working memory. The attention mechanism selects what information is passed to short-term memory. This memory enables information to be retained for a short period of time — it will be lost in 10 to 20 seconds unless it is actively rehearsed and deliberately placed in your long-term memory. Unless rehearsed, these items are lost by interference from new information or even from information previously stored. Acoustic information — things you hear — is considered easier to retain than visual information, because it is easier to rehearse sounds than data in a visual form.