Recent advances in the field of AI and neurotechnologies now seem to allow to deploy AI systems to subliminally alter a person’s behaviour, which is why it was aptly suggested that “AI has hacked the human brain” (Lexcellent 2019:67). In response to growing concerns about potential dangers posed by AI, the European Commission published in 2021 the proposal for a European Union (EU) Artificial Intelligence Act (AI Act) with the aim to make the EU “a global leader in the development of secure, trustworthy and ethical Artificial Intelligence”. The AI Act was eventually adopted in December 2023 and follows a horizontal and risk-based approach opting to regulate AI in a comprehensive and not sectoral way. Additionally, it classified AI in terms of different risks and even proposed to prohibit four categories of AI practices that were deemed to pose unacceptable risks. Among these four categories listed in Art. 5 AI Act is the use of a so-called “AI system that deploys subliminal techniques beyond a person’s consciousness”. Such systems are feared to allow to manipulate the thoughts and behavior of persons in different ways capable of causing that person or another person physical or psychological harm. Put briefly, it was suggested that AI now allows for a move from “programming computers to programming people” (Helbing 2019: 76). Equally, the United Nations Educational, Scientific and Cultural Organization (UNESCO) adopted the Recommendation on the Ethics of Artificial Intelligence in November 2021, which recognizes the profound and dynamic positive and negative impacts that artificial intelligence (AI) has on all aspects of life and particularly on the human mind.

Against the backdrop of rapid advances in the field of AI and neurotechnologies, the present paper thus proposes to briefly disciss the history of research in subliminal perception, the existing and future possibilities of AI systems to subliminally manipulate the human mind, the inherent consequences for the fundamental right of freedom of thought and the complex interdisciplinary challenges these issues pose for regulators and for law in the future.