Abstract
Recent research has demonstrated that two persons can optimally combine their observations to make better decisions when they can verbally communicate their confidence to each other. The present study investigated whether non-verbal interaction in a shared environment can be sufficient to achieve similar collective benefit. Pairs of individuals performed a localization task in a shared virtual 3D environment. In Experiments 1 and 2, partners had access to orthogonal viewpoints providing complementary information. The results showed robust collective benefit compared to individual performance from a single viewpoint, which could be obtained without any opportunity for verbal communication and even when no feedback about joint accuracy was provided (Experiment 2). When partners shared the same viewpoint (Experiment 3), collective benefit was achieved only when feedback on accuracy was provided (Experiment 3a). The findings indicate that sharing an environment can be sufficient for achieving integration of complementary perceptual information. Communicating confidence might not be necessary when an environment is shared. Another possibility is that processes for integrating interpersonally continuous information generally differ from the processes invoked when making a joint dichotomous choice.