Sludge, dark patterns and dark nudges: A taxonomy of on-line gambling platforms' deceptive design features.

Background: Gambling research has highlighted various aspects of deceptive design. For example, land-based casinos are physically designed to encourage people to gamble there for longer. Similarly, various electronic gambling products, such as electronic gaming machines, exhibit "structural characteristics" that likely encourage people to continue using them. Here I argue that the deceptive design of on-line gambling platforms is an important yet relatively neglected topic, representing the digital equivalent of land-based gambling venue design. This topic's importance is underscored by on-line gambling's international growth.

Argument: On-line gambling platforms' deceptive design features can be categorized using three terms from the interdisciplinary field of behavioral science. "Sludge" refers to detrimental frictions, which feature for example in online gambling platforms' withdrawal processes. "Dark patterns" refers to deceptive user-interface design more broadly, which includes sludge-based features and other design features such as high suggested deposit/bet sizes. Finally, "dark nudges" refers to all of these as well as other aspects of deceptive design, such as presenting gambling as a fun activity.

Conclusions: The complexity of on-line gambling platforms poses challenges for researchers, to understand what effects various design features have on behavior, and also for policymakers, to ensure fairer outcomes for people. Increased awareness and collaboration are needed from many stakeholders to better understand deceptive design features' behavioral impacts and to give them the appropriate regulatory attention in comparison to other determinants of harm.