This project examines the history and present of barriers contingent upon digital media, and looks at the way soft- and hardware assistants are designed to overcome them. General assistance systems (from simple software utilities to complex personal assistants such as Apple’s Siri) will be analyzed as well as assistive technology systems designed for people with sensory, cognitive, or motor impairments (from simple screen magnifiers and screen reader to alternative interface technologies). The project’s basic assumption is, that the history of these ›assistive media‹ is characterized by a non-anthropocentric "thought style", which to this date produces specific forms of digital accessibility. Consequently, the project does not problematize how ›normal‹ and "disabled" users participate in digital environments, but instead reconstructs the history and epistemology of a way of thinking, that conceptualizes man as an environment for the machine. Many engineers, programmers and system administrators think of "users" as "non-machines". The "human being" – for example in modern working environments or when "steering" a semi-autonomous vehicle – thus appears to be a partially incompatible component of a technologically determined system. In order to overcome these barriers within a primordial setting of "machine-human-interaction", secondary assistance systems are being developed. These "assistive media" are expected to help the machine to contact humanoid objects in its environment. The examination of these "assistive media" promises a better diachronic understanding regarding the conceptualization and negotiation of barriers as well as access points on the side of the developers. Based on this, a historically informed and critical perspective on contemporary forms of digital accessibility will be developed.Structured along three interdependent work areas, a comprehensive media historical survey of digital soft- and hardware assistants for both the "normal" user and users with sensory, cognitive or motor impairments will be conducted. Additional case studies of ›assistive media‹ allow for assessing their potentials to act as well as boundaries of their agency. Collectively all three work areas aim at answering the question, if developers and engineers of ›assistive media‹ think of the human as an environment for the machine and to what extent this historically grown "thought style" has shaped current forms of digital accessibility. The project thus addresses a major research desideratum within media studies. The applicants locate this research question within the borderland of cultural studies, disability studies, media studies, computer history and computer science and intend to answer it by combining the methods of media archeology, historical epistemology and actor-network-theory.