We've built entire management philosophies on the assumption that people perform better under pressure. Tighter deadlines. Leaner teams. More accountability. What's strange is that the evidence points in almost exactly the opposite direction - and has done for years.
What the research shows
Behavioural economists Sendhil Mullainathan and Eldar Shafir spent years studying what scarcity actually does to people - not just the practical problems it creates, but what happens inside the mind. What they found reframes the whole conversation about performance under pressure.
When you're operating under constraint, your brain has limited cognitive bandwidth - the mental resources available for attention, decision-making, planning, and self-control. Scarcity doesn't just create practical problems. It actively reduces that bandwidth by capturing attention and creating ongoing cognitive load.
Here's the mechanism. When a resource is scarce, your mind automatically focuses on that scarcity. That focus can help you deal with the immediate problem - but it comes at a cost. Everything outside the tunnel gets less attention. Not because you've chosen to ignore it. Because your cognitive system is literally allocating fewer resources to anything that isn't directly relevant to the constraint you're experiencing.
From the inside, this feels like focus. Which is precisely what makes it so hard to see.
Why we make it worse
When people start missing things - making worse decisions, losing peripheral vision, becoming short-sighted about consequences - the most common response is to apply more pressure. From management, that looks like tighter oversight and higher expectations. From inside, it sounds like: I should be better than this. I should be able to push through. Other people manage it. That internal pressure is often harder to argue with than anything a manager says out loud.
Both responses amount to the same thing: diagnosing pressure-induced short-sightedness and prescribing more pressure. The tunnel gets narrower.
If you're inside the tunnel
You probably feel focused, not compromised. That's the nature of it. The narrowing is real but it isn't visible from where you're standing. You're working hard, attending to what matters most, doing your best with what you have. The things you're missing - the options you're not seeing, the consequences you're not weighing - don't announce themselves. They're simply absent.
Which is why the inner voice that says try harder is so unhelpful and so hard to resist. More effort pointed in the same direction doesn't widen the tunnel. It just exhausts you faster.
If you're watching someone else tunnel
From outside, it can look like stubbornness, or a failure of judgment, or an unwillingness to see the obvious. It rarely is. What you're seeing is a cognitive system doing exactly what it's designed to do under constraint - prioritising the immediate and filtering out the rest.
The useful question from outside the tunnel isn't "why can't they see this?" It's "what are they carrying that I might not be accounting for?"
The constraint isn't always work
There is no shortage of management frameworks claiming to address human complexity. The problem is that most of them can't actually meet it. They're built for a simplified version of a person - consistent, separable from context, responsive to the right incentives. Real human beings navigating real lives don't work that way.
Bandwidth isn't depleted only by work pressure. Someone managing a health condition - their own or someone they love - is carrying cognitive load before they open their laptop. Someone navigating financial stress, housing insecurity, or the ambient anxiety of living through a period of geopolitical instability is already somewhere else in their mind, even when they're physically in the room. The cumulative weight of uncertainty - about personal safety, food security, the future - doesn't park itself at the door when the meeting starts.
That load is real, even when it's invisible. It affects what people can attend to, how clearly they can think, and how much they have available for the work in front of them. Most organisations implicitly assume their people arrive as fully-resourced cognitive units. They don't. None of us do.
This matters enormously when we talk about teams not seeing the full picture, or leaders making decisions that seem short-sighted in retrospect. The explanation is rarely about capability. It's almost always about what people are carrying - and how much of that carrying is invisible to everyone, including themselves.
What this means in practice
Tunnelling isn't something you can think your way out of while you're in it. That's not a failure of effort - it's the nature of the experience. The tunnel is, by definition, the limit of what you can currently see.
Recognising that you're in one is the hardest part. Not stuck because you're failing, but stuck because the tunnel is doing exactly what tunnels do.
Most of our systems haven't caught up with that yet.
How often do we design our expectations - of teams, of colleagues, of ourselves - around the human being we hope will show up, rather than making room for the one who does?
Want to explore this further?
Start here:
Sendhil Mullainathan & Eldar Shafir in their book Scarcity: Why Having Too Little Means So Much - a key inspiration for my article, the book brings together psychology and behavioural economics, it is readable and full of examples
Daniel Kahneman's Thinking, Fast and Slow - the broader cognitive bias foundation
Shorter reads:
Cara Feinberg's Harvard Magazine piece -"The Science of Scarcity." - where she explores Mullainathan's behavioural economics perspective on poverty and change
Listen:
Hidden Brain podcast episode - "You 2.0: Tunnel Vision" where Shankar Vedantam shares more on the psychological phenomenon of scarcity, accessibly told
The Knowledge Project - Episode #102 with Sendhil Mullainathan - the author of Scarcity in conversation with Shane Parrish
This post is one in my series exploring how we get stuck responding to our expectations, patterns from past experience, and assumptions rather than present reality: