Disentangling the effects of advisor consensus and advice proximity

When advice comes from interdependent sources (e.g., from advisors who use the same database), less information should be gained as compared to independent advice. On the other hand, since individuals strive for consistency, they should be more confident in consistent compared to conflicting advice, and interdependent advice should be more consistent than independent advice. In a study investigating the differential effects of interdependent versus independent advice on a judge's accuracy and confidence (Yaniv, Choshen-Hillel, & Milyavsky, 2009), advice interdependence was confounded with another variable, namely closeness of the advice to the judge's estimate. Interdependent advice was not only more consistent than independent advice but also closer to the judge's first estimate. The present study aimed at disentangling the effects of consensus and closeness of the advice by adding a third experimental condition in which interdependent (and, hence, consistent) advice was far from the judge's own estimate. We found that, as suggested by Yaniv et al., accuracy gains were indeed a consequence of advisor interdependence. However, in contrast to Yaniv et al.'sconclusions, confidence in the correctness of one's estimates was mostly a function of the advice's proximity to the participants' initial estimations, thereby indicating a social validation effect.