That people tend to have skewed perceptions of things like the number of minorities in a community is fairly well established.  A recent study from the Norwegian Business School in Oslo attempts to understand why this might be so.

The researchers surveyed 573 adults from across the United Kingdom and asked them to estimate the number of people for around 25 different characteristics, including religious, behavioral, socioeconomic, and health traits.  Each participant was also asked to rate their levels of religiousness, their political beliefs, and undergo an intelligence test.

Poor accuracy

As with previous studies, the researchers found that accuracy levels were generally low, with the least accuracy achieved in predicting the percentage of the population that is homosexual (an overestimate) and the number of adults claiming benefits (an underestimate).

Interestingly, however, the results showed that our accuracy is strongly associated with our political orientation, intelligence, and religiousness.  The data shows that the most incorrect guesses were typically involved in overestimating the size of minority groups.  The magnitude of this overestimation was linked to factors, such as one’s religiousness and political views, with these accounting for around 12% of the variation between volunteers.

The authors believe their results suggest that our predictions are heavily biased by our pre-existing beliefs, with issues such as the claiming of welfare benefits or the presence of minority groups especially prone to bias, which the authors believe is likely to be due to feelings around social competition.

“The study shows that people are generally quite inaccurate about social and demographic statistics of their own society,” the researchers conclude. “There is a clear tendency, for example, to overestimate minorities. The tendency to overestimate is related to IQ levels and a sense of being threatened.”