"I Knew It All Along": An Experimental Investigation into the Role of Hindsight Bias in the Formation of False Memories

Abstract

This study provides experimental evidence suggesting that hindsight bias functions as a reconstructive mechanism that increases the endorsement of schema-consistent lures. Integrating text-memory paradigms with Signal Detection Theory (SDT), the present research tests how an event's definitive outcome restructures the memory of antecedent details. One hundred eighty university students read an ambiguous narrative regarding a startup company. Using a hypothetical hindsight paradigm, participants were randomly assigned to a positive outcome (success), a negative outcome (bankruptcy), or a control group. Results demonstrated that participants exposed to outcome information endorsed significantly more valance-consistent “decoy” items than control participants. Corrected SDT analyses revealed that this effect was driven by both a substantial decrease in memory discriminability (d’) and a highly liberal, valence-specific shift in response criterion (c), while neutral false-alarm rates remained stable. These findings bridge the hindsight bias and misinformation paradigms, demonstrating that outcome knowledge induces a schema-congruent response bias consistent with reconstructive accounts of memory. Implications for forensic testimony and medical diagnostics are discussed alongside recommendations for future hierarchical modeling.