“How could I miss that?” A mistake may come from incomplete calculation, a misunderstood position, fatigue or an idea that monopolised your attention. No verified figure here allows us to attribute most mistakes to five biases.

These five approaches help examine your reasoning. They do not replace analysis of the position.

1. Einstellung: a familiar solution taking up too much space

Bilalić, McLeod and Gobet (2008) study problems in which a known solution may divert attention from a better one. Eye movements show that experts continue to look at elements associated with the first idea while saying they are looking for another. This is eye tracking, not an MRI demonstration.

In training, after finding a satisfactory first idea, try looking for another way to approach the position. Asking this question does not guarantee that the effect disappears.

2. Confirmation: examine the defences too

Cowley and Byrne (2004) observe that masters more readily generate continuations refuting their plans than beginners do in the tasks studied. That does not make every master immune or every beginner incapable of critical examination.

When calculating an attack, look at what happens if your opponent does not reply as expected. An intermediate check or a refusal to recapture may change the line. The article on confirmation bias explores this research.

3. Anchoring: a first estimate that persists

Tversky and Kahneman (1974) show that initial values can influence subsequent estimates, even when those values are arbitrary. Applying this to an engine evaluation requires distinguishing biased influence from reasonable use of useful information.

You can record your judgement before consulting the analysis. Then compare the reasons and variations, without reducing the entire session to the gap between two numbers. See anchoring bias.

4. Overconfidence: an expectation to check

Heck and colleagues (2025) find an average gap between claimed ability and observed rating among the players surveyed. This study does not demonstrate that a sequence of ten good moves automatically causes a drop in vigilance.

After winning material, re-examine the threats that remain. Having an advantage does not answer whether your next move is safe.

5. Availability: the memory that comes easily

In Tversky and Kahneman’s framework, the ease of recalling examples can influence estimates of frequency. A tactic you recently fell victim to may therefore occupy your attention; that remains a hypothesis to check in your own play.

Compare your memories with a set of games, including the less memorable ones. Then choose a specific difficulty to work on. Knowing a psychology term is not enough to explain a mistake or correct it.

Sources

  • Bilalić, M., McLeod, P. and Gobet, F. (2008), “Why good thoughts block better ones: The mechanism of the pernicious Einstellung (set) effect”, Cognition, 108, 652–661. Full text.
  • Cowley, M. and Byrne, R. M. J. (2004), “Chess Masters’ Hypothesis Testing”, Proceedings of the 26th Annual Conference of the Cognitive Science Society, 250–255. Full text.
  • Tversky, A. and Kahneman, D. (1974), “Judgment under Uncertainty: Heuristics and Biases”, Science, 185, 1124–1131. Full text.
  • Heck, P. R., Benjamin, D. J., Simons, D. J. and Chabris, C. F. (2025), “Overconfidence Persists Despite Years of Accurate, Precise, Public, and Continuous Feedback: Two Studies of Tournament Chess Players”, Psychological Science, 36, 732–745. Abstract.