The order effect in human abductive reasoning: an empirical and computational study

Abstract

Belief revision, a process in which one revises one's current belief in the light of new information, is an essential component of human abductive reasoning. The order effect, a phenomenon in which the final belief is significantly affected by the temporal order of information presentation, is a robust empirical finding that is not compatible with normative theories such as Bayes’ theorem. In this article we explore, both empirically and computationally, how and why the order effect occurs. Both a tactical abductive reasoning task and a learning paradigm (the UECHO model) show that although a recency effect occurs at the beginning of the training, it decreases and disappears as the training continues. We conclude that when little is known about the uncertainty and the dynamics of the environment, the order effect results from one's coherently and dynamically adaptive expectations of the statistical properties of the environment.

Keywords:

• Order effect
• Human reasoning
• Abductive reasoning
• Belief revision
• Bayes’ theorem

Acknowledgements

Some of the results reported here were presented at the 20th Annual Conference of Cognitive Science Society where the paper was awarded the Marr Prize. This research was supported by Grants N00014-95-1-0241 and N00014-96-1-0472 from the Office of Naval Research, Cognitive and Neural Sciences and Technology Division, and by a summer fellowship from the Center for Cognitive Science at The Ohio State University.