What actually narrows when an athlete performs badly under pressure

Two different failure modes

One account holds that pressure causes attention to be diverted away from the task towards worry and towards the consequences. The other holds that pressure causes attention to be turned inward onto the mechanics of a movement that had become automatic. These predict different failures, with distraction producing errors of omission and self-focus producing rigid, effortful execution.

Both appear to occur, and which one dominates seems to depend on the nature of the task and on the individual involved. Tasks that are largely self-paced and highly practised appear especially vulnerable to the second mechanism rather than the first. The practical importance is that the two would call for different responses rather than a single general instruction to relax.

Why conscious control makes skills worse

A well learned skill is executed by systems that operate faster and more smoothly than deliberate control can manage. Attending to the components of that skill interrupts the coordination between them and slows the whole sequence.

This is why an expert asked to describe what they are doing while doing it frequently performs worse than usual. The effect is largest for skills that are most automated, which means the most practised movements are the most vulnerable.

Attention narrows under threat

Physiological arousal narrows the field of attention, concentrating processing on whatever has been identified as most relevant. In moderate amounts this is useful, filtering out distraction and focusing resources on the immediate task. Beyond a certain point the narrowing excludes information the athlete needs, including peripheral awareness of other players.

The result is a performance that looks tunnel-visioned, with decisions made on less information than the situation actually offered. Where the optimal point sits varies between sports, since a sprinter and a shooter require very different levels of activation.

Arousal is not the same as anxiety

The physical activation that accompanies competition is not inherently harmful and is often necessary for performance. What matters more is how the athlete interprets that activation, since the same bodily state can be read as readiness or as threat. Athletes who interpret arousal as preparation tend to perform closer to their capability than those who read it as a warning.

This interpretation appears to be modifiable, which is one of the more practical findings in the area. Working on it with an athlete is the province of a qualified sport psychologist rather than of general encouragement.

Practising under pressure

Training environments are typically comfortable, which means skills are rehearsed under conditions unlike those where they must be produced. Introducing consequence, observation and time constraint into practice appears to reduce the size of the drop when it matters.

The effect seems to come from familiarity with the state rather than from any reduction in the pressure itself. This is why competitive simulation features in preparation programmes across a wide range of sports.

What this is not

Describing a mechanism does not mean any individual failure can be explained after the fact from the outside. Performance under pressure is affected by fatigue, illness, personal circumstances and factors no observer has access to.

Persistent anxiety that affects an athlete beyond sport is a clinical matter requiring appropriate professional support. The distinction between ordinary competitive nerves and something requiring care is one for a practitioner rather than a coach.