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Addictive Design as an Unfair Commercial Practice: The Case of Hyper-Engaging Dark Patterns

Published online by Cambridge University Press:  25 March 2024

Fabrizio Esposito*
NOVA School of Law and CEDIS, Universidade Nova de Lisboa, Lisbon, Portugal
Thaís Maciel Cathoud Ferreira
Corresponding author: Fabrizio Esposito; Email:


This article explains why hyper-engaging dark patterns should be considered unlawful in the European Union even though they are very common online, particularly on content-sharing platforms. A hyper-engaging dark pattern is a digital interface with an addictive design: it makes users spend more time interacting with the service by making use of big data analytics and one or more behavioural trait. Hyper-engaging dark patterns are a form of hypernudge. They exploit the dopamine cycle, reduce users’ autonomy and may have additional detrimental health effects. The Unfair Commercial Practices Directive should be interpreted as prohibiting them either as a form of undue influence or under the general test pursuant to Article 5. Both the Digital Services Act and the Artificial Intelligence Act can play a beneficial but merely complementary role in combatting the diffusion of hyper-engaging dark patterns.

© The Author(s), 2024. Published by Cambridge University Press

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1 “Mental bandwidth” is a term used to refer to humans’ attentional resource capacity. See, generally, TD Bhargava, “Overview: The Science of Mental Bandwidth” <> (last accessed 6 June 2023); S Mullainathan and E Shafir, Scarcity: Why Having Too Little Means So Much (London, Allen Lane 2013). The centrality of mental bandwidth for law-making in general and for consumer law in particular was recognised early on in the behaviourally informed EU legal scholarship: see A Alemanno and A-L Sibony, “The Emergence of Behavioural Policy-Making: A European Perspective” in A Alemanno and A-L Sibony (eds), Nudge and the Law: A European Perspective (Oxford, Hart Publishing 2015) p 10.

2 P Atchley, SM Lane and K Mennie, “A General Framework for Understanding the Impact of Information Technology on Human Experience” in SM Lane and P Atchley (eds), Human Capacity in the Attention Economy (Washington, DC, American Psychological Association 2021); Center for Humane Technology, “How Social Media Hacks Our Brains” <> (last accessed 5 June 2023). The distinction between automatic and controlled processes largely matches the distinction between system 1 and system 2 popularised by behavioural sciences.

3 AL Mujica, CR Crowell, MA Villano and KB Udin, “Addiction by Design: Some Dimensions and Challenges of Excessive Social Media Use” (2022) 10(2) Medical Research Archives 1, 3; NA Fineberg et al, “Manifesto for a European Research Network into Problematic Usage of the Internet” (2018) 28 European Neuropsychopharmacology 1232; G Day and A Stemler, “Are Dark Patterns Anticompetitive?” (2020) 72 Alabama Law Review 1; Center for Humane Technology, supra, note 2; VR Bhargava and M Velasquez, “Ethics of the Attention Economy: The Problem of Social Media Addiction” (2021) 31(3) Business Ethics Quarterly 321; LE Willis, “Deception by Design” (2020) 34(1) Harvard Journal of Law & Technology 116; EG Ragnhild, OD Tønnesen and MK Tennfjord, “A Scoping Review of Personalized User Experiences on Social Media: The Interplay between Algorithms and Human Factors” (2023) 9 Computers in Human Behavior Reports 100253.

4 G Moore, “The Pharmacology of Addiction” (2018) 29 Parrhesia 190; O Arias-Carrión et al, “Dopaminergic Reward System: A Short Integrative Review” (2010) 3 International Archives of Medicine 24.

5 Icahn School of Medicine at Mount Sinai, “Brain Reward Pathways” (2018) <> (last accessed 20 March 2022).

6 ibid.

7 DN Greenfield, “What Makes the Internet and Smartphone so Addictive?” in ML Sean and P Atchley (eds), Human Capacity in the Attention Economy (Washington, DC, American Psychological Association 2021) p 27.

8 A Lembke, Dopamine Nation: Finding Balance in the Age of Indulgence (London, Headline 2021) p 41.

9 Mujica et al, supra, note 3, 16.

10 N Eyal, Hooked: How to Build Habit-Forming Products (London, Portfolio 2014).

11 Center for Humane Technology, supra, note 2, 48; Greenfield, supra, note 7, 37–38.

12 Bhargava and Velasquez, supra, note 3, 6–20; F Lupiáñez-Villanueva et al, Behavioural Study on Unfair Commercial Practices in the Digital Environment: Dark Patterns and Manipulative Personalisation (“Dark Patterns Study”) (Luxembourg, Publications Office of the European Union 2020) p 33; Mujica et al, supra, note 3, 17.

13 Eyal, supra, note 10, 116–23.

14 Mujica et al, supra, note 3, 1–16.

15 Eyal, supra, note 10, 34–76.

16 The use of the term “addiction” to refer to excessive Internet use is not pacific in the literature, and some specialists prefer to use concepts like “problematic Internet use”. See B Fernandes, B Rodrigues Maia and HM Pontes, “Adição à Internet ou Uso Problemático da Internet? Qual dos Termos Usar?” (2019) 30 Psicologia USP 1.

17 World Health Organization, Public Health Implications of Excessive Use of the Internet, Computers, Smartphones and Similar Electronic Devices: Meeting Report, Main Meeting Hall, Foundation for Promotion of Cancer Research, National Cancer Research Centre, Tokyo, Japan, 27–29 August 2014 (Geneva, World Health Organization 2015) <> (last accessed 5 June 2023); P Valkenburg, A Meier and I Beyens, “Social Media Use and Its Impact on Adolescent Mental Health: An Umbrella Review of the Evidence” (2022) 44 Current Opinion in Psychology 58.

18 Greenfield, supra, note 7, 27–33.

19 Lembke, supra, note 8, 46.

20 D Susser, B Roessler and H Nissenbaum, “Technology, Autonomy, and Manipulation” (2019) 8 Internet Policy Review 2; for an overview, see F Jongepier and M Klenk, “Online Manipulation. Charting the Field” in F Jongepier and M Klenk (eds), The Philosophy of Online Manipulation (London, Routledge 2022), especially pp 22–34.

21 See, eg, Susser et al, supra, note 20; Day and Stemler, supra, note 3, 15–22; Dark Patterns Study, supra, note 12, 91–92.

22 F Esposito, “Conceptual Foundations for a European Consumer Law and Behavioural Sciences Scholarship” in H-W Micklitz, A-L Sibony and F Esposito (eds), Research Handbook in Consumer Law (Cheltenham, Edward Elgar 2018) pp 42–45, articulates this definition by critically engaging with the definition by PG Hansen, “The Definition of Nudge and Libertarian Paternalism: Does the Hand Fit the Glove?” (2016) 7 European Journal of Risk Regulation 155.

23 K Yeung, “‘Hypernudge’: Big Data as a Mode of Regulation by Design” (2017) 20 Information, Communication & Society 118. See also S Mills, “Finding the ‘Nudge’ in Hypernudge” (2022) 71 Technology in Society 102117 (focusing more on the definitional issues) and V Morozovaite, “Hypernudging in the Changing European Regulatory Landscape for Digital Markets” (2023) 15 Policy & Internet 78 (insightful for connecting hypernudges to user influence online).

24 See supra, Section II.1.

25 Esposito, supra, note 22, 42–43. For the same reason, one can delegate to more case-orientated investigation the description of which features of a specific digital service make it a HEDP; Section II.1 includes a rich list of illustrative design features that deserve to be scrutinised during such case-specific investigations.

26 As discussed by Alemanno and Sibony, supra, note 1, 18, nudges can be in the interest of the nudger or in the interest of third parties.

27 Cf C Goanta and C Santos, “Dark Patterns Everything: An Update on a Regulatory Global Movement” (Network Law Review, 19 January 2023) <> (last accessed 6 June 2023), noting that in the current debate we run the risk that everything is a dark pattern, so that ultimately nothing really is. See the useful case-by-case analysis in F Di Porto and A Egberts, “The Collective Welfare Dimension of Dark Patterns Regulation” (2023) 29 European Law Journal 114.

28 Regulation (EU) 2022/2065 of the European Parliament and of the Council of 19 October 2022 on a Single Market for Digital Services [2022] OJ L277/1 (DSA), Recital 67. See also Directive (EU) 2023/2673 of the European Parliament and of the Council of 22 November 2023 amending Directive 2011/83/EU as regards financial services contracts concluded at a distance and repealing Directive 2002/65/EC [2023] OJ L2023/2673, which includes a definition of dark patterns in Recital 42 and introduces the prohibition of their use in distance contracts in the Consumer Rights Directive (new Article 16e) but regrettably only for financial contracts, which are not HEDPs.

29 Dark Patterns Study, supra, note 12, 35–39. From a comparative perspective, it is useful to consider also FTC, “Bringing Dark Patterns to Light” <> (last accessed 26 June 2023).

30 Dark Patterns Study, supra, note 12, 39.

31 See infra, Section IV.

32 Dark Patterns Study, supra, note 12, 39. See also Commission Notice – Guidance on the Interpretation and Application of Directive 2005/29/EC of the European Parliament and of the Council Concerning Unfair Business-to-Consumer Commercial Practices in the Internal Market [2021] OJ C526/1, 100–01.

33 See, generally, Susser et al, supra, note 20; Dark Patterns Study, supra, note 12; A Mathur, M Kshirsagar and J Mayer, “What Makes a Dark Pattern … Dark?: Design Attributes, Normative Considerations, and Measurement Methods” in Proceedings of the 2021 CHI Conference on Human Factors in Computing Systems (ACM 2021) <> (last accessed 26 June 2023); J Luguri and LJ Strahilevitz, “Shining a Light on Dark Patterns” (2021) 13 Journal of Legal Analysis 43. Recently, Di Porto and Egberts (supra, note 27) have emphasised the collective harms caused by dark patterns. However, these collective harms are best understood as direct and indirect harms to consumers (users), similarly to what happens in EU competition law; the reason for this is that they have the effect of reducing the capacity of the market mechanism to work to the benefit of consumers; see F Esposito, The Consumer Welfare Hypothesis in Law and Economics: Towards a Synthesis for the 21 st Century (Cheltenham, Edward Elgar 2022) especially pp 120–22 (on direct and indirect harm) and 176–80 (on the overall account of the internal market built around the goal of consumer welfare maximisation).

34 Directive 2005/29/EC of the European Parliament and of the Council of 11 May 2005 concerning unfair business-to-consumer commercial practices in the internal market and amending Council Directive 84/450/EEC, Directives 97/7/EC, 98/27/EC and 2002/65/EC of the European Parliament and of the Council and Regulation (EC) No 2006/2004 of the European Parliament and of the Council [2005] OJ L149/22.

35 C-146/16 Verband Sozialer Wettbewerb eV v DHL Paket GmbH [2017] ECLI:EU:C:2017:243.

36 G Howells, T Wilhelmsson and C Twigg-Flesner, Rethinking EU Consumer Law (London, Routledge 2017) p 53.

37 UCPD, Arts 5–8. “Transactional decision” means “any decision taken by a consumer concerning whether, how and on what terms to purchase, make payment in whole or in part for, retain or dispose of a product or to exercise a contractual right concerning the product, whether the consumer decides to act or to refrain from acting”. UCPD, Art 2(k). According to the CJEU, “transactional decision” means “any decision directly related to the decision whether or not to purchase a product”. See Case C-281/12 Trento Sviluppo srl, Centrale Adriatica Soc. Coop. Arl v Autorità Garante della Concorrenza e del Mercato [2013], paras 35, 36 and 38.

38 Guidance on the Interpretation and Application of UCPD, supra, note 32; Dark Patterns Study, supra, note 12, 6.

39 See, generally, T Wu, The Attention Merchants: The Epic Scramble to Get Inside Our Heads (New York, Knopf 2016).

40 Digital asymmetry is characterised by relational, architectural and data-driven factors; see N Helberger et al, “Choice Architectures in the Digital Economy: Towards a New Understanding of Digital Vulnerability” (2022) 45 Journal of Consumer Policy 175.

41 See the discussion in F Esposito, “Theories of Harms, Digital Vulnerability and Structural Asymmetries: A Methodological Proposal with Three Illustrations for New Consumer Law Research” in A de Franceschi and C Crea (eds), Digital Vulnerability in EU Private Law (Baden-Baden, Nomos forthcoming); F Esposito and J Morais Carvalho, “The Hyper Dismal Reality and EU Law: Structural Asymmetry Is a Matter of Weakness, Not Just Consumer Vulnerability” (on file with the authors). However, we derive this claim by analogy with similar considerations previously articulated by A-L Sibony, “Can EU Consumer Law Benefit from Behavioural Insights? An Analysis of the Unfair Practices Directive” (2014) 22 European Review of Private Law 901; Esposito, supra, note 22, 66–73. See also J Morais Carvalho and S Fernandes Garcia, “Vulnerabilidad y Consumo: ¿Tiene Sentido una Distinción entre Consumidores Vulnerables y No Vulnerables?” in E Isler Soto and D Jarufe Contreras (eds), Vulnerabilidad y Capacidad – Estudios sobre Vulnerabilidad y Capacidad Jurídica en el Derecho Común y de Consumo (Santiago, Rubicón Editores 2022).

42 UCPD, Arts 2(e) and 5.

43 C-281/12 Trento Sviluppo srl, supra, note 36, para 36.

44 Dark Patterns Study, supra, note 12, 70.

45 All HEDPs have the same purpose and follow the same logic, but the way each platform applies them varies.

46 Dark Patterns Study, supra, note 12, 92–93.

47 See supra, Section II.2.

48 Day and Stemler, supra, note 3, 4.

49 Eyal, supra, note 10.

50 R Shotton, The Choice Factory: 25 Behavioural Biases That Influence What We Buy (Petersfield, Harriman House 2018).

51 AK Pradeep, The Buying Brain: Secrets for Selling to the Subconscious Mind (Hoboken, NJ, Wiley 2021).

52 S Weatherill, The Internal Market as a Legal Concept (Oxford, Oxford University Press 2017).

53 N Helberger et al, EU CONSUMER PROTECTION 2.0 Structural Asymmetries in Digital Consumer Markets (BEUC 2021).

54 C-295/16 Europamur Alimentación SA v Dirección General de Comercio y Protección del Consumidor de la Comunidad Autónoma de la Región de Murcia [2017] ECLI:EU:C:2017:782, para 42.

55 Valkenburg et al, supra, note 22, 60.

56 ibid, 66.

57 L Hongjun, “On Theoretical and Methodological Value of Epistemic Translation Studies” (2022) 22 Contemporary Foreign Languages Studies 34. See also F Esposito, “Some Notes on Interdisciplinary Theoretical Disagreements between Law and Economics” (2021) 7 Latin America Legal Studies 55.

58 T van Leeuwen, “Three models of interdisciplinarity” in R Wodak and P Chilton (eds), A New Agenda in (critical) Discourse Analysis: Theory, Methodology and Interdisciplinarity (Amsterdam, John Benjamins 2005) pp 3–18.

59 On the difficult relation between scientific inquiry and legal practice, see, generally, S Haack, Evidence Matters: Science, Proof, and Truth in the Law (Cambridge, Cambridge University Press 2014).

60 Arts 6 and 7 UCPD; Howells et al, supra, note 36, 63–65.

61 Dark Patterns Study, supra, note 12, 120–23.

62 E Mik, “The Erosion of Autonomy in Online Consumer Transactions” (2016) 8 Law, Innovation and Technology 1, 32.

63 Helberger et al, supra, note 53, 51.

64 UCPD, Art 8.

65 Art 2(j) UCPD describes undue influence, saying that it “significantly limits the ability” instead of “it is likely to significantly limit”. Considering the writing of Art 8 and the UCPD’s framework, it seems reasonable to consider that likelihood is sufficient for all sorts of aggressive practices. See Helberger et al, supra, note 40, 70.

66 UCPD, Art 2(j).

67 UCPD, Art 9.

68 Howells et al, supra, note 36, 66.

69 Helberger et al, supra, note 53, 68.

70 P Hacker, “Manipulation by Algorithms. Exploring the Triangle of Unfair Commercial Practice, Data Protection, and Privacy Law” (2021) 29(1–2) European Law Journal 142.

71 See infra, Section III.3, for more detail.

72 See, recently, M Grochowski and M Taborowski, “Effectiveness and EU Consumer Law: The Blurriness in Judicial Dialogue” in F Casarosa and M Moraru (eds), The Practice of Judicial Interaction in the Field of Fundamental Rights (Cheltenham, Edward Elgar 2022).

73 C-428/11 Purely Creative Ltd and Others v Office of Fair Trading [2012] ECLI:EU:C:2012:651, para 49.

74 C-54/17 Autorità Garante della Concorrenza e del Mercato v Wind Tre SpA and Vodafone Italia SpA [2018] ECLI:EU:C:2018:710.

75 C-628/17 Prezes Urzędu Ochrony Konkurencji i Konsumentów v Orange Polska [2019] ECLI:EU:C:2019:480.

76 Orange Polska, supra, note 77, paras 49 and 50.

77 Hacker, supra, note 70, 10–11.

78 See, eg, K Bongard-Blanchy et al, “‘I Am Definitely Manipulated, Even When I Am Aware of It. It’s Ridiculous!’ – Dark Patterns from the End-User Perspective”, Designing Interactive Systems Conference 2021 (Association for Computing Machinery 2021) <> (last accessed 26 June 2023).

79 Cf R Uuk, Manipulation and the AI Act (Future of Life 2022) <> (last accessed 6 June 2023), 2.

80 Cf P Aggarwal, S Jun and J Huh, “Scarcity Messages: A Consumer Competition Perspective” (2011) 40 Journal of Advertising 19.

81 In relation to nudges, see, in particular, R Baldwin, “From Regulation to Behaviour Change: Giving Nudge the Third Degree” (2014) 77 The Modern Law Review 831.

82 Eg Guidance on the Interpretation and Application of UCPD, supra, note 32, 37.

83 On the notion of subliminal stimulus, see A Sand and ME Nilsson, “Subliminal or Not? Comparing Null-Hypothesis and Bayesian Methods for Testing Subliminal Priming” (2016) 44 Consciousness and Cognition 29.

84 See, recently, Grochowski and Taborowski, supra, note 72.

85 See, extensively, F Galli, Algorithmic Marketing and EU Law on Unfair Commercial Practices (Berlin, Springer 2022).

86 Guidance on the Interpretation and Application of UCPD, supra, note 32, 100–104; Dark Patterns Study, supra, note 12, 122.

87 See, generally, Jongepier and Klenk, supra, note 20.

88 See infra, Section IV, for more detail.

89 Howells, et al, supra, note 36, 58.

90 UCPD, Art 5(2).

91 UCPD, Art 2(h).

92 J Trzaskowski, “Data-Driven Value Extraction and Human Well-Being under EU Law” (2022) 32 Electronic Markets 447.

93 UCPD, Art 2(e).

94 See supra, Section II.1.

95 Dark Patterns Study, supra, note 12, 72.

96 Guidance on the Interpretation and Application of UCPD, supra, note 32, 99.

97 DSA, Art 93.

98 This article does not apply to providers of online platforms that qualify as micro or small enterprises within the meaning of the Annex to Recommendation 2003/361/EC. See DSA, Art 29(1).

99 ibid.

100 There seems to be no doubt in the literature that the term “cover” leads to the inapplicability of Art 25 DSA as soon as the practice falls within the scope of either the UCPD or the General Data Protection Regulation (GDPR). See, eg, J King, “Do the DSA and DMA Have What It Takes to Take on Dark Patterns?” (Tech Policy Press, 23 June 2022) <> (last accessed 6 June 2023); MR Leiser, “Dark Patterns: The Case for Regulatory Pluralism between the European Union’s Consumer and Data Protection Regimes” in E Kosta, R Leenes and I Kamara (eds), Research Handbook on EU Data Protection Law (Cheltenham, Edward Elgar 2022); M Martini and C Drews, “Making Choice Meaningful – Tackling Dark Patterns in Cookie and Consent Banners through European Data Privacy Law” (2022) SSRN Electronic Journal <> (last accessed 6 June 2023).

101 C-319/20 Meta Platforms Ireland v Bundesverband der Verbraucherzentralen und Verbraucherverbände – Verbraucherzentrale Bundesverband e.V. [2022] ECLI:EU:C:2022:322.

102 J Bahrke, “Digital Services Act: Commission Designates First Set of Very Large Online Platforms and Search Engines” (2023) <> (last accessed 26 June 2023).

103 DSA, Art 34(1).

104 DSA, Arts 34(1)(b) and 35(1).

105 DSA, Recital 83.

106 DSA, Arts 35(1) and 35(1)(a).

107 See, generally, M Husovec and I Roche Laguna, “Digital Services Act: A Short Primer” (2022) SSRN Electronic Journal <> (last accessed 6 June 2023); SF Schwemer, “Digital Services Act: A Reform of the e-Commerce Directive and Much More” in A Savin (ed.), Research Handbook on EU Internet Law (Cheltenham, Edward Elgar 2022).

108 Commission, “Proposal for a Regulation of the European Parliament and of the Council Laying Down Harmonised Rules on Artificial Intelligence and Amending Certain Union Legislative Acts” (“AI Act”), COM (2021) 206 final, Art 5(1).

109 AI Act, Recital 16.

110 AI Act, Art 5(1)(a).

111 See supra, Section II.1.

112 See supra, Section II.2.

113 Cf RJ Nuewirth, The EU Artificial Intelligence Act. Regulating Subliminal AI Systems (London, Routledge 2023), reviewed by Y Doker and HD Seval, “The EU Artificial Intelligence Act: Regulating Subliminal Al Systems (Routledge Research in the Law of Emerging Technologies) by Rostam J. Neuwirth – The Digital Constitutionalist” (9 December 2022) <> (last accessed 6 June 2023); see also M Franklin et al, “Missing Mechanisms of Manipulation in the EU AI Act” (2022) 35 The International FLAIRS Conference Proceedings <> (last accessed 7 June 2023).

114 Cf P Grady, “EU’s AI Act Resurrects Subliminal Messaging Panic” (Center for Data Innovation, 21 October 2022) <> (last accessed 6 June 2023); Uuk, supra, note 79.

115 European Parliament resolution of 12 December 2023 on addictive design of online services and consumer protection in the EU single market (P9_TA(2023)0459), para 3. The resolution is based on the following report: K Van Sparrentak (Rapporteur) for the Committee on the Internal Market and Consumer Protection, “Report on addictive design of online services and consumer protection in the EU single market” (2023/2043(INI)).

116 European Parliament resolution of 12 December 2023, supra, note 116, para 6.

117 R Brownsword, “The Theoretical Foundations of European Private Law: A Time to Stand and Stare” in R Brownsword, H-W Micklitz, L Niglia and S Weatherill (eds), The Foundations of European Private Law (Oxford, Hart Publishing 2011).