New Study Suggests That Fatigue is Most Detrimental for the Narrative Mind

I'm one of the authors on a new study by Dr. Mustafa Ozkaynak's research team, which looks at how emergency department (ED) nurses change their decision-making process when they become fatigued. In a previous paper, we found that fatigue was common in ED nurses, particularly toward the end of their work shift, and that nurses' fatigue was more often characterized as physical rather than mental or emotional -- in other words, this really represented being physically tired at the end of the day, not being burned-out or depressed. Nevertheless, physical fatigue has important effects on nurses' decision-making in the ED.

Based on nurses' qualitative reports, fatigue has mixed effects on their clinical performance. Nurses said that they definitely cut corners when they were tired, for example in terms of documentation in the electronic health record. They felt that they were less careful about double-checking things, and might be more likely to make snap decisions. We were particularly interested in whether this affected their antibiotic stewardship practices. The nurses believed that being tired did not change their clinical care outcomes, even though it did affect their process by making them cut corners, "satisficing" rather than optimizing their workflow. Nevertheless, they allowed for the possibility that they could be mistaken.

In general, Two Minds Theory suggests that the nurses' view of their own performance was likely correct. Although there is a well-known gap between people's confidence in their performance and more objective measures (the Dunning-Krueger effect), the gap is not as great as is commonly supposed. Furthermore, well-learned and highly-practiced behaviors, like a nurse providing clinical care in the ED, tend to be maintained by habit alone. That's true even when we aren't fully able to pay attention to what we are doing (e.g., because of fatigue). This highlights the fundamental power of the Intuitive Mind: Even when we aren't at our best, our so-so performance is still pretty darned good. Most of the time, we can get through life by relying on biases and heuristics. The fact that they often work is the reason that they exist in the first place.

The gap between nurses' optimal and fatigued levels of performance is most likely to become evident when a task requires focused attention, such as reading values from some clinical lab test, or when attention must be sustained over time, such as when performing a multi-step task. Attention is a limited resource controlled by the Narrative Mind, and nurses' reports suggested that their Narrative capacities were diminished when they became fatigued. It also takes Narrative-level work to overcome biases in situations where they may be too limiting. The old clinical adage "if you hear hoofbeats, think horses" is a good one 99% of the time, but it's wrong whenever a "zebra" situation comes along.

Mustafa suggests that nurses are more likely to default to Intuitive-level thinking when fatigued, and that they also have less capacity to override Intuitive-level thinking. The first part isn't necessarily a bad thing, because habits and routines can often carry the day. But when a task requires more attention, or when a nurse's Intuitive first reaction is wrong, that's when fatigue can lead to serious errors, because the backup Narrative system has been compromised by fatigue.