Links Between Users' Online Social Network Homogeneity, Ambiguity Tolerance, and Estimated Public Support for Own Opinions.

False consensus effect (FCE) refers to a cognitive bias of relative overestimation of public support for one's own opinion. FCE has been linked to selective social interaction with like-minded people as well as to selective exposure to attitude-consistent information. Previous studies tested these links mostly in offline settings. However, it is assumed that FCE is also affected by the homogeneity of users' online contact network, the extent to which they use online social network (OSN), and their individual tendency to avoid ambiguous information. Two online studies with a total of 380 participants aged 18-35 years were conducted to test these hypotheses through a multilevel modeling approach. In Study 1, participants with a more homogeneous online network, longer daily OSN usage time, and lower ambiguity tolerance displayed significantly higher FCE. The effects of network homogeneity and ambiguity tolerance were replicated in Study 2. The implications of these findings are interpreted in the context of prior studies on FCE as well as the notion of OSN as "echo chambers."