Algorithmic and Human Collusion

53 Pages Posted: 24 Nov 2021

See all articles by Tobias Werner

Tobias Werner

Heinrich Heine University Dusseldorf - Duesseldorf Institute for Competition Economics (DICE)

Date Written: November 10, 2021


As self-learning pricing algorithms become popular, there are growing concerns among academics and regulators that algorithms could learn to collude tacitly on non-competitive prices and thereby harm competition. I study popular reinforcement learning algorithms and show that they develop collusive behavior in a simulated market environment. To derive a counterfactual that resembles traditional tacit collusion, I conduct market experiments with human participants in the same environment. Across different treatments, I vary the market size and the number of firms that use a self-learned pricing algorithm. I provide evidence that oligopoly markets can become more collusive if algorithms make pricing decisions instead of humans. In two-firm markets, market prices are weakly increasing in the number of algorithms in the market. In three-firm markets, algorithms weaken competition if most firms use an algorithm and human sellers are inexperienced.

Keywords: Artificial Intelligence, Collusion, Experiment, Human–Machine Interaction

JEL Classification: C90, D83, L13, L41

Suggested Citation

Werner, Tobias, Algorithmic and Human Collusion (November 10, 2021). Available at SSRN: or

Tobias Werner (Contact Author)

Heinrich Heine University Dusseldorf - Duesseldorf Institute for Competition Economics (DICE) ( email )

Universitaetsstr. 1
Duesseldorf, NRW 40225


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