Bernoulli's Critical Error: Neglecting Reference Points

Key Insight

A significant flaw in the long-standing utility theory is its failure to incorporate the concept of a reference point. This theory assumes that an individual's utility, or level of happiness, is determined solely by their absolute state of wealth. Consequently, it predicts that two individuals with the same current wealth should be equally happy, regardless of their financial history.

However, real-world experience contradicts this, demonstrating that happiness is heavily influenced by recent changes in wealth relative to a specific reference point. For instance, someone who has recently gained $4 million to reach $5 million would be elated, while another who lost $4 million to reach the same $5 million would be despondent. This 'reference dependence' is ubiquitous, akin to how the perception of sound or light intensity is always relative to a preceding stimulus.

Because this model lacks a reference point, it cannot explain why the identical objective outcome might be perceived as a gain by one person and a loss by another. This oversight prevents the theory from accounting for varying risk preferences, such as a person with $1 million being delighted by gaining $1 million, while another with $4 million is miserable losing $2 million to arrive at the same $2 million, leading to different choices under risk.