Blanking on something you actually know well is not a sign you were unprepared. Research on choking under pressure names two specific, well studied causes for exactly this experience, and they call for different fixes. Knowing which one is happening to you matters more than trying harder at either.
Choking is not the same as not knowing
Sian Beilock, a cognitive scientist who has spent her career studying performance under pressure, defines choking with real precision. It is performing worse than your actual capability, specifically because of what is at stake, not a general lack of skill or preparation. That distinction matters. Choking happens to people who have the real underlying ability. It is not evidence of a gap in competence, however it feels in the moment.
Two different causes, not one
The research identifies two separate mechanisms behind freezing up, and they pull in opposite directions. One is distraction, worry about the outcome eats up the attention the task itself needs, leaving less room for the thing you are actually trying to do. The other is explicit monitoring, pressure causes you to suddenly pay close, conscious attention to something you would normally do without thinking, and that attention disrupts it. A fluent speaker who starts consciously watching their own grammar mid sentence is a clean example of the second pattern.
These need opposite responses. Giving your mind something small and task relevant to hold onto helps with the first. Trusting the automatic version of yourself and moving faster helps with the second. Applying the wrong one makes things worse, not better.
Working out which one is yours
The useful question, before the moment rather than during it, is whether you are more likely to spiral into worry about the outcome, or to suddenly overthink something you normally do fluently. Most people have a pattern they default to, and it tends to show up the same way across different high stakes situations, not just one specific type of moment.
Where to start
Before your next high stakes moment, name honestly which pattern tends to happen to you. If it is worry crowding out focus, prepare one small, concrete thing to anchor your attention on, a specific opening line, a physical action, something simple enough not to add to the load. If it is overthinking something usually automatic, plan to move slightly faster than feels comfortable rather than slowing down to check yourself.
Notice which one actually shows up next time, and adjust your read of yourself if it turns out to be the other one.
Reading your own pattern accurately, rather than assuming the generic advice for choking applies to you specifically, is something you are better placed to judge with a little honest attention than any article can tell you in advance. What this gives you is the two real options, so you are choosing between them rather than guessing.
There is a specific way to prepare for a high stakes moment that reduces both patterns at once, without needing to diagnose which one you have first, and it is worth knowing before the next one arrives.