In 2011, a study of Israeli judges found that in the early sessions of the day, prisoners had roughly a 65% chance of parole. By the end of each session, that probability had fallen to nearly zero. After a break, it returned to 65%. The judges didn’t vary. The cases didn’t get harder. The types of prisoners didn’t change. What changed was the judges’ cognitive resources.
I’ve thought about that study many times, working with leaders. Not because they’re making parole decisions, but because the underlying dynamic is the same. When cognitive load climbs beyond a certain threshold, the quality of thinking degrades in ways we can’t detect from the inside. The brain doesn’t send a notification. What it sends instead is a set of signals, many of which look like the opposite of the problem. Five stand out.
You feel sharp
One of the paradoxes of high cognitive load is that it produces a sense of focus. When the brain is overwhelmed, it narrows attention, conserving resources by shutting down peripheral processing. You are concentrating. You feel sharp. What you’ve lost is your awareness of everything outside this tunnel: the team’s emotional state, the signal buried in an email chain, the strategic risk sitting just adjacent to the immediate problem. I encounter this regularly with leaders under sustained pressure. They often describe feeling in the zone at precisely the moment their breadth of thinking has contracted most severely. Focus that comes with a loss of peripheral awareness isn’t a cognitive strength. It’s a cognitive symptom.
Your confidence is up
Here is the deeper paradox: the more cognitively overloaded a leader becomes, the more confident they tend to feel. Under high cognitive load, the brain falls back increasingly on what is often called System 1 thinking — fast, intuitive, pattern-based processing. The supervisory function that questions, second-guesses and looks for counterevidence — System 2 — is the first thing to go. The internal voice that says, “Are you sure about this?” goes quiet. Leaders interpret the silence as certainty. And research has repeatedly shown that individuals under cognitive load express higher confidence in their judgments precisely when their decision quality has degraded most. If you’ve been working at full throttle for several weeks and find you have unusually few doubts, that’s not necessarily clarity. It’s probably just that your self-monitoring has gone offline.
You become more decisive
Another consistent finding is that people under high load become significantly more likely to act quickly on new information — in studies, about 22% more likely. This matters because decisiveness is something leaders are encouraged to display. The executive who cuts through, doesn’t dither, and makes the call is celebrated by organizations. And sometimes their judgment really is good. But under cognitive load, the same behavior has a different cause. System 1 is operating without oversight from System 2. The decision may be fast and feel confident, but it’s quicker because it hasn’t been examined. So, if your decisions are all landing in the same direction of favoring speed over scrutiny, always pulling toward the familiar over the novel, then that pattern is worth interrogating.
People start to irritate you more
This one is less obvious. Research has found that high cognitive load reduces both behavioral and neural empathic responses. An overloaded brain is simply less able to read other people’s emotional states. This isn’t a character shift. It’s a resource allocation problem. The same neural processing capacity that handles complex reasoning also handles social inference, and when you’re cognitively overloaded, the brain economizes. Leaders in this state typically don’t notice the shift in their social processing. What they notice is that colleagues seem to be underperforming, or that meetings feel fractious, or that people appear harder to manage than usual. The irritation of frustration is then a secondary symptom. Because when you can’t readily interpret others’ reactions, their behavior becomes harder to anticipate, which makes it feel more difficult.
You’re making dumb mistakes
Finally, the most obvious and concrete signal. Under sustained cognitive load, working memory errors multiply; not in complex, novel tasks, but in familiar ones. Things like missing emails you’d normally catch, writing responses with simple errors, and walking into meetings without documents you’ve specifically prepared. Such out-of-character lapses are working memory failures – the brain carrying too many processes simultaneously, so routine execution is the first thing that drops. Most leaders attribute these to tiredness. They’re right that tiredness is involved. But the errors are often diagnostic of something deeper, like a memory system running over capacity, not just running slow.
What you can do about it
Most of the standard advice, rest more and take breaks, isn’t wrong, but it operates at the wrong level. Because it treats cognitive load as something to recover from rather than something to prevent. Take these two techniques.
The first is what psychologists call implementation intentions: if-then rules set in advance about how you’ll make decisions under specific conditions. “If I’ve had fewer than four hours’ sleep, I’ll get a check on any high-stakes decisions.” The point isn’t the specific rule. It’s the pre-commitment, because when System 2 is depleted, you can’t rely on it to notice the depletion. So, you need a solution that engages in its absence.
The second is chronotype alignment: wherever possible, scheduling your highest-load cognitive work at your neurologically optimal time, not when the calendar happens to be free. It’s not always possible, of course, but some redistribution may be. For most morning types, that’s two to four hours after waking. After that point, the windows for genuinely high-quality strategic thinking are limited, and decisions made in them carry the implicit costs documented in the parole study.
Prevention, then, is better than cure. Not least because, after the fact, we may not believe we did anything wrong. Remember those Israeli judges? When told about the research findings, the judges didn’t believe them and disputed them. They were so confident their decisions had been consistent and fair throughout the day that it was easier for them to believe the data was wrong than that they were. Their confidence in their own judgment was, like all of ours, entirely unrelated to its actual reliability.
