  The European Union's Artificial Intelligence Act aims to regulate
manipulative and harmful uses of AI, but lacks precise definitions for key
concepts. This paper provides technical recommendations to improve the Act's
conceptual clarity and enforceability. We review psychological models to define
"personality traits," arguing the Act should protect full "psychometric
profiles." We urge expanding "behavior" to include "preferences" since
preferences causally influence and are influenced by behavior. Clear
definitions are provided for "subliminal," "manipulative," and "deceptive"
techniques, considering incentives, intent, and covertness. We distinguish
"exploiting individuals" from "exploiting groups," emphasising different policy
needs. An "informed decision" is defined by four facets: comprehension,
accurate information, no manipulation, and understanding AI's influence. We
caution the Act's therapeutic use exemption given the lack of regulation of
digital therapeutics by the EMA. Overall, the recommendations strengthen
definitions of vague concepts in the EU AI Act, enhancing precise applicability
to regulate harmful AI manipulation.
