An Investigation On Belief Bias Effects In Deductive Reasoning

Belief bias is the tendency that people accept believable conclusions and reject unbelievable conclusions when they are asked to evaluate the validity of an inference. Conclusion evaluation paradigm which is one of the main research methods in psychology of deduction asks subjects to decide whether a conclusion is necessarily followed from the given premises. By adopting conclusion evaluation paradigm, the goal of this research was to investigate the patterns of belief bias in three types of deductive reasoning, compare three models of belief bias, examine the relationship between premises believability and belief bias effect, and explore developmental pattern of belief bias and the effects of logic teaching on belief bias. The main conclusions were as follows:First, the pattern of belief bias effect was different in varied types of deduction. The main effect of conclusion believability existed in all types of deductive reasoning, however, the interaction of conclusion believability and validity did not always occur in the problems that have the same logical form in different deductive inference tasks.Second, the accounts of belief bias, such as Selective Scrutiny Model, Misinterpreted Necessity Model, and Mental Model Theory, can not explain all phenomena found in the research. Comparatively, Mental Model Theory can predict and explain most of belief bias effects by modifications, and it especially specifies the processes of belief affects reasoning, therefore showing its superiority over the other models.Third, the effect of premises believability on reasoning was similar in all types of deduction, that is, the effect of conclusion validity was stronger when the premises were believable than they were unbelievable. The believability of premises could change the size of belie bias effect, but did not affect the patterns of belief bias effect.Fourth, belief bias effects were not reduced with age. The developmental pattern of belief bias was related to the logical form of a reasoning task, as well as the subjects' ability of a particular reasoning form. Logic teaching did not change the size and pattern of belief bias effect.