A second family of biases concerns how people see themselves and what they own. The Dunning-Kruger effect, named for Kruger and Dunning's 1999 Cornell studies on logic, grammar, and humor, describes how low-skill individuals overestimate their ability while experts often underestimate theirs, because experts are aware of what they do not know. The self-serving bias complements this by attributing success to oneself and failure to circumstance, while the fundamental attribution error and the actor-observer asymmetry do the reverse for others: their behavior is read as character, while our own is explained by situation. Asking "what situation might explain this?" and consulting a trusted critic are practical counters.
Ownership and attachment distort valuation in predictable ways. The endowment effect, demonstrated in Knetsch's mug experiment (people demanded roughly twice the price to sell a mug they had just been given), shows that willingness to accept exceeds willingness to pay. The IKEA effect extends this: people overvalue things they have built themselves. Status quo bias, and its close cousin the default effect (organ donation rates differ enormously between opt-in and opt-out countries), makes the current state of affairs feel safer than alternatives, even when alternatives would be chosen if no current state existed.
Loss aversion, a core component of prospect theory, captures that losses feel roughly twice as painful as equivalent gains feel good. It drives related phenomena such as the zero-price effect ("free" disproportionately increases attractiveness) and the certainty effect (outcomes seen as certain are overweighted relative to merely probable ones). Ambiguity aversion (the Ellsberg paradox) extends the same logic to risk: people prefer known risks to unknown ones, even at worse expected value. Together these biases explain why framing, default settings, and ownership cues so powerfully shape choice without removing options.