Pictorial versus textual information and the ratio-bias effect.

The ratio-bias effect refers to the perception that a low probability event is more likely when presented in the form of a larger, e.g., 10-in-100, than smaller, e.g., 1-in-10, numerical ratio. This phenomenon has been used to help distinguish between rational-analytic versus heuristic-automatic ways of problem solving. In the current study, responding in accordance with the ratio bias was more prevalent when choices were presented pictorially as opposed to textually. Results are discussed with respect to how various factors, including mode of information presentation, may affect whether problems are solved via heuristic, automatic processes as opposed to effortful, analytic strategies.