Social influence bias: a randomized experiment.
Our society is increasingly relying on the digitized, aggregated opinions of others to make decisions. We therefore designed and analyzed a large-scale randomized experiment on a social news aggregation Web site to investigate whether knowledge of such aggregates distorts decision-making. Prior ratings created significant bias in individual rating behavior, and positive and negative social influences created asymmetric herding effects. Whereas negative social influence inspired users to correct manipulated ratings, positive social influence increased the likelihood of positive ratings by 32% and created accumulating positive herding that increased final ratings by 25% on average. This positive herding was topic-dependent and affected by whether individuals were viewing the opinions of friends or enemies. A mixture of changing opinion and greater turnout under both manipulations together with a natural tendency to up-vote on the site combined to create the herding effects. Such findings will help interpret collective judgment accurately and avoid social influence bias in collective intelligence in the future.
School of Business Administration, The Hebrew University of Jerusalem, Mount Scopus, Jerusalem, 91905 Israel.
Lev
L
Muchnik
Sinan
S
Aral
Sean J
SJ
Taylor
D032763:Behavior Control; D015982:Bias; D003657:Decision Making; D017144:Focus Groups; D033062:Friends / Q000523:psychology; D006801:Humans; D007360:Intelligence; D020407:Internet; D011057:Politics; D011639:Public Opinion; D012931:Social Environment