The belief‐bias effect in reasoning: The development and activation of competence

Abstract

The aim of this study was (1) to examine the development of the influence of personal belief about the truth or falsity of conclusion deduced from syllogistic reasoning and (2) to determine whether a procedure of activation of previously established knowledge could improve reasoning performance. A total of 271 17‐year‐olds and 215 university students were given one of a series of four paper‐and‐pencil tests. The results indicated that the effect of belief on reasoning is greater among adolescents for logical forms having a valid conclusion (valid forms), but that belief‐bias is greater among adults for logical forms with no valid conclusion (invalid forms). The activation procedure significantly improved performance both among adolescents and among adults, although the effects were limited. Finally, a relation was found between subjects' explicit knowledge of the empirical‐logical distinction and their ability to reason with an abstract problem. The results were interpreted as indicating that the effect of belief on reasoning is not linear but involves a complex relation between reasoning Competence and task difficulty.