Score contribution per author:
α: calibrated so average coauthorship-adjusted count equals average raw count
People often receive feedback influenced by external factors, yet little is known about how this affects self-serving biases. Our theoretical model explores how multi-dimensional uncertainty allows additional degrees of freedom for self-serving bias. In our primary experiment, feedback combining an individual’s ability and a teammate’s ability leads to biased belief updating. However, in a follow-up experiment with a random fundamental replacing the teammate, unbiased updating occurs. A validation experiment shows that belief distortion is greater when outcomes originate from human actions. Overall, our experiments highlight how multi-dimensional environments can enable self-serving biases.