Shining a Light on Dark Patterns

Article Source: Journal of Legal Analysis, Vol. 13, pp. 43-109, 2021
Publication Date:
Time to Read: 2 minute read
Written By:

 Jamie  Luguri

Jamie Luguri



Some user interfaces include “dark patterns” that exploit cognitive bias to manipulate users. Two experiments show that subtle dark patterns are more dangerous, because consumers are less likely to reject them.


Policy Relevance:

The Federal Trade Commission (FTC) should audit interfaces for dark patterns. Dark patterns violate laws against deceptive advertising.


Key Takeaways:
  • Some user interfaces are deliberately designed to exploit cognitive biases, confusing users into buying goods or services they do not want or into revealing personal information they would prefer not to disclose.
  • Two large-scale experiments show how consumers behave when exposed to dark patterns.
    • Users exposed to mild (subtle) dark patterns were more than twice as likely to sign up for a dubious service as those in the control group.
    • Users exposed to aggressive dark patterns became four times as likely to sign up.
  • The experiments invited consumers to purchase identity theft protection, and included the following design elements:
    • A screen inviting consumers to “accept and continue” or “other options.”
    • For the study of aggressive patterns, three screens of information on identity theft, which the consumer was required to read.
    • Confusing trick questions, such as "Are you sure you want to decline this free identity theft protection," with the options being "No, cancel," and "Yes."
  • Mild dark patterns engendered no backlash from consumers, and should be considered the most dangerous.
    • Aggressive dark patterns did generate backlash.
    • Well-educated consumers resisted mild dark patterns better than less educated consumers.
  • Dark patterns involving hidden information, trick questions, and obstruction were among the most effective in causing consumers to make decisions they later regretted or did not understand.
    • Loaded language and bandwagon effects were also effective.
    • “Must act now” messages were not effective if the service was costly.
  • Both experiments showed that dark patterns made consumers indifferent to the price of the service; interface design rather than cost drove the consumers’ decisions.
  • Judicial rulings show that dark patterns may violate federal or state laws barring the use of unfair or deceptive trade practices, and might vitiate consent under the common law of contracts.
    • Advertisements disguised as news or consumer feedback are deceptive.
    • Falsely informing consumers that their computers were infected with malware is deceptive.
  • The Federal Trade Commission should audit interfaces for dark patterns.
    • “A-B testing” can identify dark patterns so manipulative they should be considered illegal, as well as being used to maximize profits.
    • In these tests, many consumers are exposed to designs identical except for one element, allowing the elements that yield the strongest consumer response to be identified.



Lior Strahilevitz

About Lior Strahilevitz

Lior Strahilevitz is the Sidley Austin Professor of Law at the University of Chicago Law School. His teaching and research interests include law and technology, privacy, intellectual property, property and land use, contracts, and motorist behavior.

Professor Strahilevitz is a member of the American Law Institute, and from 2013 to 2019 was an adviser to the American Law Institute Data Privacy Principles Project. He has been an Advisory Board Member for the Future of Privacy Forum since 2012. Professor Strahilevitz has won numerous awards for excellence in teaching.