Review: Mistakes were made (but not by me!)

Why we justify foolish beliefs, bad decisions, and hurtful acts

Carol Tarvis & Elliot Aronson (2007, updated 2016)

Mistakes were made is a book about cognitive dissonance theory. Over 7 chapters, we are introduced to the mechanisms of cognitive dissonance, whereby one’s concept of oneself is able to remain stable despite one having taken actions which appear hard to reconcile with that self-concept. The ways in which dissonance theory, or more frequently, the self-justification it predicts, explains knavery both great and small: from quarrels and rudeness, through tunnel-vision in clinical and criminal investigations, to the apotheoses of divorce and warfare. An 8th chapter new to this edition adds an analysis of those who resist self-justification and live with the discomfort of dissonance.

The diversity of uses to which dissonance theory is put is impressive, but occasionally troubling, as when we are told that ‘Dissonance reduction, therefore, will protect high self-esteem or low self-esteem, whichever is central to a person’s core self-concept’ (p.42). Self-esteem, presumably, is a spectrum, with most ordinary people lurking somewhere on the positive side of neutral self-esteem and a few particularly down-on or up themselves people on the low or particularly high end. People with neutral, or more neutral self-esteem, on this theory, ought to be immune to dissonance, because it has neither high nor low self-esteem to protect. Or perhaps for neutral people all actions cause dissonance, and so self-justification has to work twice as hard.1

Another issue for dissonance theory as presented is whether simpler mechanisms, such as ambiguity reduction, provide adequate explanations for the various phenomena handled by dissonance theory, such as selective memory, confirmation bias, and peseverance bias.2 In general, the explanation of dissonance reduction is invoked for a vast array of case studies, and in some places it feels like a significant stretch, especially when person-level mechanisms are invoked for crowd-level phenomena.3

Throughout the book is informative and entertaining in the case studies it discusses, including very real an important social issues such as the damage caused by interrogation techniques which are liable to elicit false confessions, and ‘recovered memory’ therapy whereby unhappy patients are coaxed into believing horrific fantasies of abuse by family and friends.

Reflecting on the theory as a whole, I wonder how it meshes with more mechanistic frameworks for human behaviour, such as predictive processing. What use might it serve a prediction machine of a brain to maintain a consistent self-concept to the exclusion of evidence to the contrary? Likewise, from a Bayesian Brain perspective, how can we account for the dismissal of evidence as opposed to the integration of evidence into our core self-concept (even if the evidence counts little in the grand scheme of things).

For any reader there’s a lot to take away here: whether or not you’re persuaded by the central theory, the array of phenomena discussed really helps demonstrate that everyone makes mistakes, and the urge to deny them or double down on them is pervasive. It also highlights how these things are not always problematic, but can escalate problems if allowed to roam unchecked. For me, the phrase which brought the biggest smile to my lips was a second-hand quote from a speech by Kennedy after the Bay of Pigs fiasco: ‘An error does not become a mistake until you refuse to correct it.’ (p.282)


  1. I don’t think that’s likely, either. 

  2. Also known as the ‘sunk costs fallacy’. 

  3. The authors describe a neuroscience ‘tit-for-tat’ experiment where participants were asked to replicate pressure applied to their finger by another participant, who would then replicate that pressure, and so on. The experiment showed an escalation in pressure, explained by the perception of pain received as being greater than the pain inflicted. This mechanism, we are told, ‘helps explain why two boys who start out exchanging punches on the arm as a game soon find themselves in a furious fistfight. And it explains why two nations find themselves in a spiral of retaliation.’ (p. 247, emphasis added)