We tend to justify a purchase by overlooking any faults seen

The Sour Grapes Effect

We tend to justify a purchase by overlooking any faults seen

We’re more likely to submit a positive review of a product purchased than a negative one, desiring our past choices as rational and well-made. Retailers could embrace this bias, reinforcing a user’s correct choice post-purchase.

Cohen & Goldberg (1970). The Dissonance Model in Post-Decision Product Evaluation. Journal of Marketing Research.

This built-in mechanism aims to make us feel better about any poor decisions we make. It’s especially the case when we buy something expensive.

Given our emotional investment when preparing to buy something - any research done, our pre-existing brand loyalty and any influential advertising seen - many consumers will refuse to admit, in light of any shortcomings experienced with the product, that their decision was made in poor judgement.

This curious idea stems from the Principle of Commitment. Renowned psychologist Robert Cialdini highlights our deep-seated psychological desire to stay true to that commitment, because it directly relates to our self-image. We therefore attempt to rationalise any product problems seen, justify the choice made and protect our self-image.

Takeaways for decision-makers

  1. Product folk can encourage our desire to be consistent by having customers make an initial, small commitment, whether that’s a text-based / verbal statement of intent or a small down-payment. Future requests can then be made that reinforce this initial commitment.

  2. Retailers could embrace this bias, celebrating a user’s ‘correct’ choice post-purchase. This could be done by popping a note in their delivery order telling customers how much others also loved the product, giving applicable quotes and ratings, for instance. Such an experience will soothe any post-purchase tension experienced, especially for more expensive orders.

  3. As we desire our past choices to be rational and well-made, we’re more likely to recommend or submit a positive review of a product purchased than a negative one. Customers could be encouraged to share such a review. This can be done by framing a review call-to-action to suggest that the product experience is indeed great, and if they’d like to confirm that.

  4. Consumer representatives should encourage a slowing-down approach to the purchasing process, advising the public to commit ample time to widespread research prior to a decision being made.