Why Does Anxiety Make It Hard to Think?

You need to think clearly. You’re anxious. The thinking gets worse.

It’s one of the most frustrating loops in human experience: the stakes make you anxious, the anxiety impairs performance, the impaired performance raises the stakes, the stakes deepen the anxiety. The things that matter most are the things you’re most likely to mess up in a particular way — not from lack of effort or ability, but from the specific cognitive cost of high arousal.

The Yerkes-Dodson Curve

In 1908, Robert Yerkes and John Dillingham Dodson published findings from experiments on mice that established a principle that has held up for over a century: the relationship between arousal and performance is not linear. It’s an inverted U.

At low arousal (drowsy, disengaged), performance is poor. As arousal increases, performance improves — more alertness, more focus, more motivation. But above a certain threshold, additional arousal degrades performance. The optimal point is in the middle: alert and engaged but not overwhelmed.

The optimal arousal level varies by task. Simple, well-practiced tasks can tolerate high arousal — and in some cases benefit from it. Complex tasks requiring careful reasoning, creativity, or fine motor control have a lower optimal arousal point. Under high anxiety, complex thinking degrades first.

This is the Yerkes-Dodson law, and it’s been replicated across species, tasks, and arousal types.

What’s Actually Getting Impaired

The specific mechanism by which anxiety impairs thinking involves working memory.

Working memory is the mental workspace where you hold and manipulate information in real time. It’s where you keep track of the steps of a math problem while solving it, the key points of an argument while making it, the relevant context while navigating a conversation. Working memory has limited capacity — typically described as 7 ± 2 items, though recent work puts usable capacity even lower for complex material.

Anxiety places demands on this limited system. Worry — the cognitive component of anxiety, the running thread of threat-related thoughts — occupies working memory capacity. When you are anxious, part of your working memory is dedicated to monitoring the threat, rehearsing worst-case scenarios, and generating solutions to problems that may not exist.

This leaves less working memory capacity for the task you’re actually trying to do. The result is not the subjective feeling of impairment — it’s actual impairment. Sian Beilock’s research on choking under pressure found that high-stakes performance causes high-working-memory individuals to drop to the level of low-working-memory individuals, because the high-WM individuals are especially capable of generating and ruminating on threat-relevant worries that consume their own capacity.

Higher working memory protects against many things, but it doesn’t protect against this. The more working memory you have, the more of it anxiety can steal.

The Amygdala-PFC Tension

The prefrontal cortex (PFC) handles executive function, complex reasoning, and emotional regulation. The amygdala handles threat detection and emotional response.

These regions exist in a tension: the PFC can suppress amygdala reactivity through top-down regulation (this is what emotional regulation is — prefrontal control of amygdala response). But the amygdala can also suppress PFC function — during high threat, the amygdala signals via norepinephrine and corticotropin-releasing factor to downregulate the very prefrontal circuits that would otherwise moderate the anxiety response.

This is sometimes called amygdala hijack: under sufficient emotional arousal, the PFC loses influence and the emotional system drives behavior with less top-down moderation than usual.

The logic of this is straightforward: if you’re being chased, careful deliberative reasoning is less useful than fast, automatic threat-response behavior. The amygdala hijack evolved for exactly that situation. The problem is that “being chased” and “taking an important exam” produce similar levels of physiological arousal, and the system doesn’t distinguish well between them.

Attention Narrowing

Under high anxiety, attention narrowing occurs: the range of information processed contracts toward threat-relevant cues.

In real danger, this is useful. You don’t want to be attending to peripheral details when something is trying to kill you. Threat-relevant information should dominate attention.

In a performance context — a test, a presentation, a conversation that matters — attention narrowing means you’re more likely to be tracking signals of failure (the questioner’s skeptical expression, the slight pause in a conversation, your own increasing heart rate) than focusing on the content of what you’re doing. The monitoring system has co-opted the attentional system.

This is the mechanism behind one of anxiety’s cruelest features: the more self-conscious you become during a performance, the worse the performance gets — because the attention that should be on the task is on yourself.

Why It Evolved This Way

The system makes more sense if you consider what it was designed for.

The ancestral threat was physical and immediate: a predator, a hostile stranger, a dangerous situation requiring fast physical response. For this kind of threat, the hijack is appropriate — reduce deliberation, narrow attention, prioritize fast motor action, keep the working memory clear of irrelevant considerations.

The modern threat environment includes prolonged uncertainty, social evaluation, abstract stakes, and performance under judgment — situations that require the opposite of what the anxiety response provides. You need deliberation when preparing a legal argument, not rapid motor response. You need broad attention when solving a novel problem, not tunnel focus on threat cues.

The mismatch between what the anxiety response delivers and what modern demanding tasks require is not a bug in the system. It’s a system running normally in a context it was not designed for.

What Helps

The most effective interventions for anxiety-impaired performance work in different ways:

Expressive writing before a high-stakes task, where you write out your worries for 10 minutes, appears to reduce the intrusive working memory demands of anxious rumination — essentially offloading some of the worry onto paper, freeing working memory capacity for the task.

Reappraisal: interpreting physiological arousal as excitement rather than anxiety produces performance improvements. The physiological state (elevated heart rate, cortisol, norepinephrine) is identical in anxiety and excitement; the cognitive label changes how those signals get integrated.

Practice until automated: tasks that are fully automated don’t require working memory and are therefore more resistant to anxiety impairment. The test anxiety effect that reduces high-WM individuals to low-WM performance doesn’t apply to skills that have become procedural. Choking requires something to over-think.

The anxiety isn’t the problem. The problem is that the anxiety is solving for the wrong threat.

Your brain read the stakes as a predator and optimized for fight or flight.

The exam was not a predator.

But the system doesn’t ask.