Proceedings of the Annual Meeting of the Cognitive Science Society

Classic base-rate neglect studies have been consistently criticised for lacking ecological validity. A study by Welsh & Navarro (2012) found this heuristic was significantly reduced when participants perceived the base rate as more relevant. The present study aims to study this phenomenon through a more realistic scenario while simultaneously capturing participants' written reasoning. Using mixed-methods, participants (N = 2,052) read an engaging scenario regarding a person who committed infidelity and containing a base-rate and specific information where the contextual information regarding the base-rate was manipulated. They were then asked to provide an estimate of the person's likelihood to cheat in the future. Results show that each of our three manipulations to the context of the base rate are significant in affecting participants' estimates, supporting Welsh and Navarro's findings. Analysis of participants' written reasoning demonstrates the sophistication and nuance of participants' engagement with the base-rate, challenging the original view of this supposed heuristic.