Todennäköisyyspainotus

Todennäköisyyspainotus, or probability weighting, is a concept in decision theory and behavioral economics that describes how individuals subjectively perceive and adjust probabilities when making choices under uncertainty. Instead of treating probabilities in a strictly objective or linear manner, people often distort them. This distortion is not random but follows a systematic pattern.

Typically, people tend to overweight small probabilities and underweight large probabilities. This means that unlikely events are perceived as more likely than they actually are, and very likely events are perceived as less likely than they are. For example, someone might be overly concerned about winning a small lottery prize (due to overweighting the small probability of winning) or might underestimate the risk of a highly probable but serious negative outcome.

This phenomenon helps explain various behaviors, such as why people buy lottery tickets or insurance policies. The perceived value of these choices is influenced not just by the potential outcomes but by the distorted probabilities assigned to them. Pioneering work in this area was done by psychologists Daniel Kahneman and Amos Tversky through their prospect theory, which formalized the concept of probability weighting. Understanding probability weighting is crucial for modeling human decision-making, especially in situations involving risk and uncertainty.