1 Wise or mad crowds? The cognitive mechanisms underlying 2 information cascades 1 1;2 3 Alan N. Tump (
[email protected]), Tim Pleskac , Ralf H. J. M. Kurvers1 1Max Planck Institute for Human Development, Center for Adaptive Rationality, Lentzeallee 94, 14195 Berlin, Germany 2University of Kansas, Department of Psychology, Jayhawk Blvd, Lawrence, KS 66045, USA 4 November 26, 2019 5 Abstract 6 Whether getting vaccinated, buying stocks, or crossing streets, people rarely 7 make decisions alone. Rather, multiple people decide sequentially, setting the stage 8 for information cascades whereby early-deciding individuals can influence others' 9 choices. To understand how information cascades through social systems, it is es- 10 sential to capture the dynamics of the decision-making process. We introduce the 11 social drift-diffusion model to capture these dynamics. We tested our model using 12 a sequential choice task. The model was able to recover the dynamics of the social 13 decision-making process, accurately capturing how individuals integrate personal 14 and social information dynamically over time and when they timed their decisions. 15 Our results show the importance of the interrelationships between accuracy, con- 16 fidence, and response time in shaping the quality of information cascades. The 17 model reveals the importance of capturing the dynamics of decision processes to 18 understand how information cascades in social systems, paving the way for appli- 19 cations in other social systems. 20 21 Keywords: collective intelligence, information cascades, sequential decision-making, social 22 information, confidence, herding, conformity, social impact, collective behaviour 23 Main 24 In many situations|be they financial investments, consumer choices, or simply crossing the street| 25 one is generally not making a decision alone.