HOW likely is someone to move up the economic ladder? A new study by Alberto Alesina, Stefanie Stantcheva and Edoardo Teso of Harvard University compares perceptions of social mobility in five countries—America, Britain, France, Italy and Sweden—against actual levels. It finds that Americans tend to be optimistic, while Europeans tend to be too pessimistic. An American born to a household in the bottom 20% of earnings, for instance, only has a 7.8% chance of reaching the top 20% when they grow up. Americans surveyed thought the probability was 11.7%.

Politically left-leaning respondents are naturally more doubtful about the scale of social mobility, and are more likely to support redistributive government policies, than conservative ones. But Mr Alesina and his colleagues also find that people of different political stripes also respond differently to new information. When given pessimistic information about social mobility, left-wing respondents became even more likely to support economic redistribution. In contrast, right-wing respondents’ support for redistribution did not change. Perhaps, the authors suggest, right-leaning respondents see government as “the cause of the problem, not the solution”.