The IKEA Effect: Why We Overvalue What We Build Ourselves

What is this page about?

An explainer of the IKEA effect, the cognitive bias by which people overvalue objects they helped assemble or create regardless of actual quality, formally documented by Norton, Mochon, and Ariely in 2012. It distinguishes it from the endowment effect, traces the intellectual lineage (effort justification, not-invented-here bias), covers the cognitive science of self-relevant creation (competence, self-extension, self-signaling), the foundational studies, and four case studies (Build-a-Bear, open-source developer attachment, cooking, and strategy consulting), plus limits such as incomplete tasks eliminating the effect.

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Every accepted correction to this page is recorded with the exact change, so readers can see how the page improved over time.

1. 11 July 2026 · corrected by Emir Baycan

   2 corrections applied: Norton, Mochon & Ariely (2012) found ~60-65% higher WTP, not nearly five times | Wansink, Payne & Chandon (2007) was published in Obesity, not the Journal of Consumer Research (per article's own reference list)

   Before

   builders valued their creations at nearly five times what non-builders offered for the same objects | Wansink, Payne, and Chandon, in a 2007 paper in the Journal of Consumer Research | FAQ answer: 'bid approximately five times more for their own boxes'

   After

   builders valued their creations roughly 60 percent higher than what non-builders offered | Wansink, Payne, and Chandon, in a 2007 paper in the journal Obesity | FAQ answer corrected to: 'bid roughly 60 percent more for their own boxes'

   Why: Body content and bibliography were already correctly fixed (60 percent figure, Obesity journal) at time of verification. Found the same 'approximately five times more' fabrication still present in the FAQ JSON-LD schema (Q1 'What is the IKEA effect?') and corrected it to match the body's 60 percent figure. Verified clean on re-fetch.

   View the full record →

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