Despite the leveling bandwidth, we don't call situations where we lose "down". So, how does a situation become suitable for applying levelling?
Simply put, there are two types of errors in poker: errors of judgment and errors of psychology. Evaluation is your ability to quantify the optimal play in a static situation. Errors occur when a sub-optimal strategy is chosen instead of the optimal one, despite all the information available. Psychological errors are caused by mispredicting information that is not even available yet.
A rating error is caused by an error in a player's existing poker theory. If he makes such an error, he has not looked carefully enough at the ranges, hands, odds or anything else before making his decision, even though all the information is right in front of his eyes. A psychological error is one in which a player needs more information to make a decision against his opponent, but no longer has it. And then there is a situation in which levelling can be applied.
For example, if the action ended at your 4-bet/call off ATo against someone who shoves very narrowly (and you know his range), then this is a rating error. But if you call an overbet on the river when the board is completely dry and your hand is clear, thinking that your opponent is expecting you to fold, and it turns out that he has the nuts, then you can call that a psychological error, or a flat.
What is meant when it is said that an FPS player has "lowered himself"? Now we can be clearer about what this means. To downgrade oneself means to make a mistake in an assessment situation due to a psychological situation, or to make a mistake in a levelling situation due to a non-level situation. In normal language, it means that the right play was obvious, but the player somehow convinced himself to do it the other way around. The correct way would have been to use valuation analysis and frequencies ("his belf's frequency is high in this situation, so I'll make the call"), but the player incorrectly tried to connect the situation to the levelling problem and thus made a false conclusion.
The difference could be defined as follows: the situation of levelling is not purely psychological, but at the same time binary. It sounds a bit silly to say that your frequency has let you down or that your opponent's entire strategy has done so. When we talk about levelling, we have to use a reductionist approach to poker. We should look at the hand as a particle made of atoms and the decision as an X or Y decision.
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