How to Beat Decision Fatigue

Описание: A nurse in Pennsylvania had been on her feet for twelve hours. She was supposed to go home, but the unit was short-staffed, so she stayed. During that overtime, a patient was diagnosed with cancer and needed two chemotherapy doses. She administered the first, placed the second in a drawer, and headed home.


She forgot about the second dose.


It wasn't discovered until the next day. The patient was fine; they got the treatment in time. But think about what happened. This wasn't a careless nurse. This was a dedicated professional who stayed late to help her team. Her skills didn't fail. Her knowledge didn't fail. Her energy failed, and her judgment went with it.


That's the trap. We assume our thinking stays constant, that the brain in hour fourteen is the same brain that showed up in hour one. It's not.


Last episode, we tackled deciding under uncertainty (https://www.philmckinney.com/how-to-s...) . But fatigue does something different. Uncertainty makes you hesitate. Fatigue makes you stop caring.
Why Your Brain Makes Worse Decisions by Evening

You've probably heard the popular saying: "Making too many decisions wears you out, so by evening your judgment is shot."


That idea dominated psychology for twenty years. Researchers believed decision-making drained from a limited mental reserve, like a battery running down.


Then, independent labs tried to reproduce those results at scale, and the effect vanished. One study, 23 labs, over 2,000 people, found nothing. A second, 36 labs, 3,500 people, same result.


The experience is real, though. People do make worse decisions after a long day of mental effort. What was wrong was the explanation. Your brain doesn't drain like a battery. After sustained effort, it shifts priorities. It starts favoring speed and ease over accuracy. Not because it can't think carefully, but because it decides careful thinking isn't worth the effort.


Decision fatigue isn't your brain shutting down. It's your brain quietly lowering its standards without telling you.
Decision Fatigue in the Real World

That science isn't abstract. It plays out every day.


Researchers at Brigham and Women's Hospital tracked over 21,000 patient visits. Doctors prescribed unnecessary antibiotics more frequently as the day went on. Not because afternoon patients were sicker. Because saying "here's a prescription" is easier than explaining why you don't need one. Five percent more patients received antibiotics they didn't need, purely because of timing.


The same pattern shows up everywhere. Surgeons make more conservative calls later in the day. Hand hygiene compliance drops across a twelve-hour shift. Financial analysts grow less accurate with each additional stock prediction they make in a single day. The drift always goes in the same direction: toward whatever requires the least effort.


That drift explains something we've been exploring across this series. When you're exhausted, someone else's conclusion isn't just tempting, it's a relief. The algorithm's recommendation saves you from having to evaluate. The expert's opinion saves you from forming your own. That's mindjacking, finding the open door. Fatigue doesn't just degrade your thinking. It makes you grateful to hand it over.
Your Four Warning Signals

Knowing the science is useful. But what matters more is catching fatigue in yourself before it costs you. Here are four signals that your judgment is compromised.


Signal 1: The Default Drift. Someone proposes a plan that sounds... fine. Not great, not terrible. Two hours ago, you'd have pushed back, asked harder questions. Now you just nod. You're not agreeing because you're convinced. You're agreeing because disagreeing takes energy you no longer have.


Signal 2: The Irritability Spike. A colleague asks a reasonable question, and it feels like an interruption. When your emotional response is out of proportion to the situation, it's not the situation. Your reserves are low.


Signal 3: The Shortcut Reflex. A decision that should take twenty minutes takes thirty seconds. You skip the analysis, go with your gut. There's a version of this that sounds like confidence. "I trust my instincts." But late in the day, that phrase is often code for "I'm too tired to think this through."


Signal 4: The Surrender. You stop forming conclusions and start borrowing them. Someone says, "I think we should go with Option B" and you feel a wave of relief. Not because Option B is right, but because you no longer have to figure it out. That relief is the signal. When outsourcing, your judgment feels like a gift instead of a loss, you're running on empty.


If two or more of these show up at the same time, stop. Your judgment isn't reliable right now. Don't trust it with anything that matters.
Four Moves to Protect Your Judgment

Those signals tell you something's wrong. Here's what to do about it.


Move 1: Postpone it. Move the decision to a high-ene...