People who are good with numbers make better decision-makers. That’s according to Ellen Peters and colleagues at Decision Research who found the less numerate among 100 students were more likely to be influenced by so-called ‘framing effects’.
For example, less numerate students tended to rate a student’s exam performance as better on a 7-point scale if they were told she had answered 74 per cent of items correctly in her exam, than if they were told she had answered 26 per cent incorrectly. By contrast, more numerate students were less affected by the way such information was presented. (Numeracy was tested with 11 maths questions on probability).
In another experiment, students were given the chance to win cash if they picked a red bean from a jar. Less numerate students were more likely than numerate students (33 per cent vs. 5 per cent, respectively) to choose to take their chances with a jar that had 9 red beans out of 100, than with a jar that had 1 red bean among 10, probably because they were swayed by the sight of more red beans in the first case, even though the odds were poorer.
The differences in performance between the more and less numerate students couldn’t be explained by differences in their general intelligence, which was also measured.
“We believe that low-numeracy decision makers are left with information that is less complete and less understood, lacking the complexity and richness available to the more numerate”, the researchers concluded.
Peters, E., Vastfjall, D., Slovic, P., Mertz, C.K., Mazzocco, K. & Dickert, S. (2006). Numeracy and decision making. Psychological Science, 407-413.
Post written by Christian Jarrett (@psych_writer) for the BPS Research Digest.