Why do we think we’re more likely to win at the big casino versus the small one?
Category Size Bias
, explained.What is Category Size Bias?
Category size bias describes our tendency to believe outcomes are more likely to occur if they are part of a large category rather than part of a small category, even if each outcome is equally likely. While the bias is based on experimental studies that have been successfully replicated, the interpretation of the evidence remains mixed.
Where it occurs
Imagine you’re watching cross-country skiing in the Winter Olympics, a sport with a prominent field of Norwegians. You know next to nothing about cross-country skiing, but your friend points to the TV, where a woman is lining up for the race and asks you to consider the likelihood she’s the woman to win Gold. The name Ragnhild Haga appears along the bottom of the screen next to a Norwegian flag.
Regardless of Haga’s actual likelihood of winning the race, your prediction shouldn’t be influenced by the number of Norwegians also lining up for the race, yet this is an error people sometimes make. Even if the field is evenly matched, we may assume that a single outcome coming from a larger category is more likely than a smaller one.
