Information Processing, Human Error and the Learning Process — Page 156, Lesson 241

Let’s start with a classic experiment that really drives home the limits of divided attention. In 1950, a researcher named Cherry set up a test where two different voices, each carrying different information, were played into a subject’s left and right ears at the same time. The key finding was that the subject could not process information from both ears simultaneously. Instead, they could only switch their attention from one voice to the other, back and forth in turn. That tells us something fundamental: our central processor cannot handle two separate streams of information at once. Now, let’s talk about what we call lack of attention. It’s important to understand that the mind is always paying attention to something — except during sleep. So for a pilot, the real danger isn’t a complete absence of attention; it’s the poor management of attention. That means you’re paying attention to the wrong item at the wrong time. That’s a critical distinction. Stress has a major effect on attention, and we’ve already touched on this in Chapter 7. Stress influences attention especially during times of low arousal and high arousal. Because our ability to process information is limited, this directly affects the level of performance we can achieve. Let’s break that down into three zones. First, low arousal. Think of a long cruise phase — your attention can wander, and as a result, information is either missed entirely or misinterpreted. One way to address this is by generating artificial flight deck workloads, like running through checklists or setting up for the next phase of flight, to keep your mind engaged. Second, optimum arousal. At this level, the central processor is at its most efficient. That’s the sweet spot where your performance is best. Third, high arousal overload. When arousal gets too high, the limited channel capacity of the central processor becomes a real problem. There’s a danger of attention becoming narrowed — what we call funnelling — so that important information gets disregarded. If the system is overloaded, the attention mechanism may even reject additional information altogether. This overload comes in two types: - Qualitative overload: the information is perceived as beyond your attentional capacity — the task itself feels too difficult. - Quantitative overload: there are simply too many responses to be made in the time available. As we’ve seen, the relationship between workload and performance can be represented as an inverted ‘U’ curve — the Yerkes-Dodson curve you’ll see in Figure 7.2. Finally, let’s look at the symptoms of overload. These vary from individual to individual, but the most common include: a sharp degradation of performance, funnelling of attention or focus, regression (reverting to earlier, less effective behaviours), mental blocks, mood swings, restlessness, trembling, and panic. These are the warning signs that your attentional capacity is being exceeded.