In August 2026, the European Commission published a call for tenders seeking research on how online marketplace design influences user behaviour. The study, mandated under the Digital Services Act (DSA), will examine how interface choices affect what people buy, how much they pay, and whether they make informed decisions. The research is needed because the answer is not straightforward: dark patterns have become normalised across large platforms, and their effects on consumer behaviour are only beginning to be understood.

Key Takeaways

  • The European Commission is funding a study on how marketplace design influences user behaviour, mandated by the Digital Services Act.
  • Dark patterns make the platform's preferred outcome easier than the user's preferred outcome, using techniques such as confirmshaming, hidden costs, forced action, and visual hierarchy.
  • The DSA requires large platforms to assess and mitigate systemic risks, including risks related to dark patterns.
  • The study may lead to regulatory requirements that mandate specific design changes on large platforms.
  • The AliExpress case — a €550 million fine under the DSA — demonstrates that regulators are beginning to enforce these obligations.

What Dark Patterns Look Like

Dark patterns are interface design choices that steer, pressure, or deceive users into decisions they would not otherwise make. The term was coined by user experience researcher Harry Brignull in 2010, and the taxonomy has expanded significantly since then. The European Commission's research will draw on this established framework.

Common types of dark patterns include:

**Confirmshaming**: A button that says "No thanks, I don't want to save money" instead of a simple "Decline." The user is shamed into accepting the option they do not want.

**Hidden costs**: Adding fees, subscriptions, or optional items to a cart at the last step, when the user has already invested time in the checkout process. This exploits the sunk-cost fallacy: the user is more likely to accept the extra cost than abandon the transaction.

**Forced action**: Requiring users to opt out of data collection or marketing emails through a multi-step process, while opting in is a single click. This exploits the status quo bias: people tend to stick with the default option.

**Visual hierarchy**: Making the option the platform prefers (typically "Subscribe" or "Accept all") larger, brighter, or more prominent, while the alternative is greyed out or hidden behind a link. This exploits the salience bias: people are more likely to select the option that attracts their attention.

**Roach motel (easy to get in, hard to get out)**: Making it simple to sign up for a subscription but difficult to cancel. This is regulated in several jurisdictions through requirements for cancellation processes to be as simple as sign-up processes.

**Sneak into basket**: Adding items to a shopping cart without the user's explicit consent, often during free trials or promotional offers.

Why the DSA Study Matters

The DSA, which entered full force in 2024, requires "very large online platforms" (those with over 45 million users in the EU) to assess and mitigate "systemic risks" — including risks related to dark patterns. The new study is a direct response to that obligation.

The study will examine how design elements like default settings, information presentation, and choice architecture affect user behaviour in real marketplace conditions. It will address questions such as: Do users notice hidden costs? How does the placement of "Accept" and "Reject" buttons affect cookie consent rates? What design changes reduce the likelihood of accidental purchases?

The findings could lead to new regulatory requirements. If the research identifies specific design patterns that consistently harm users, the Commission may use its powers under the DSA to require platforms to modify them. This could include minimum standards for cancellation processes, transparency requirements for pricing, and limits on the use of visual hierarchy to steer users.

The AliExpress Precedent

In July 2026, the European Commission fined AliExpress €550 million under the DSA for failing to adequately address dark patterns and other systemic risks. The case is significant because it demonstrates that the DSA's enforcement mechanisms are operational and that the Commission is willing to impose substantial penalties for non-compliance.

The fine was based on findings that AliExpress's interface design made it difficult for users to cancel orders, that mandatory fields were not clearly marked, and that the platform used visual hierarchies that steered users toward purchasing decisions they did not intend. The Commission also found that the platform's complaint-handling system was not sufficiently accessible.

Limits and Counterarguments

Regulation alone will not eliminate dark patterns. The design industry has spent decades developing techniques that maximise conversion rates, and these techniques are deeply embedded in platform economics. If one platform stops using dark patterns, it may lose market share to competitors that continue to use them.

There is also a definitional challenge: where is the line between persuasive design and dark patterns? Not every interface that encourages a particular action is manipulative. The European Commission's research will need to establish clear criteria for distinguishing between acceptable persuasive design and harmful dark patterns.

Some critics argue that the focus on platform design distracts from more fundamental issues, such as the business models that incentivise platforms to use dark patterns in the first place. Advertising-driven revenue models, for example, create strong incentives to maximise user engagement and data collection, and dark patterns are one tool for achieving those goals.

What Happens Next

The European Commission's study is expected to take 12 to 18 months, with interim findings published as they become available. The results will inform potential regulatory action under the DSA, including the development of binding codes of conduct for platform design.

In the meantime, the AliExpress case has set a clear precedent. Platforms that use dark patterns face significant financial penalties, and the Commission has demonstrated that it is willing to enforce the DSA's requirements.

Age of Algorithms Perspective

Dark patterns are not a failure of design — they are a feature of a system in which the platform's incentives and the user's interests are not aligned. The regulatory response under the DSA is an attempt to realign them, but it is unlikely to succeed without broader changes to the business models that make dark patterns profitable.

For readers of Age of Algorithms, the most practical defence against dark patterns is awareness. The techniques are not invisible; they are designed to be difficult to notice. Once you know what confirmshaming looks like, it becomes harder to fall for it. The European Commission's research is a step toward making that awareness more widespread.