171 Towards Coupled Interaction - Practical Integration of Physiological Signals Inês Oliveira, Luís Duarte, Nuno M. Guimarães, Luís M. Carriço and Ovidiu Grigore Keywords: Physiological Signals, Interaction Design, Coupled Interaction Abstract The search for usable systems has highlighted design criteria like adaptiveness or accessibility support. The systemic view of interaction, encompassing the human user, artifacts, language, methodology and training, influenced the design principles of past and current systems. How- ever, users have been taken as black boxes, communicating with the machine through more or less sophisticated languages. The recognition of cognitive or emotional status of the user and its integration in the interaction design is the basis of the coupled interaction notion, a view of the structural coupling concept derived from more general system theories. A dimension of this coupling strategy is the integration of human physiological signals. Rea- lizing the constraints of current systems, this paper describes technical experience gained from the use of EEG (electroencephalography) for evaluation of “reading” tasks and from the use of ECG (electrocardiography) information as an input modality, and tries to build an integrated view for interaction design with these physiological multimodalities. Introduction HCI has evolved in multiple directions but, in spite of the innovative interaction opportunities, the integration of the intrinsic human status has not been considered with a comparable level of depth. The consideration for the physical/physiological (phy-) state or information of a human user can be a fundamental element in the interaction and in the overall experience design. The evolution of acquisition technology for human phy- information (like EEG, ECG or dermal activity, EDA ), the accuracy of the processing techniques, and the understanding of the mapping between “human phy- features” and cognitive activities (sleep, reading, math reason- ing, stress or fatigue) build up a framework for design and development of “coupled interaction environments”. The notion of coupled interaction is inspired by theoretical concepts of human cognition and systems interaction, such as the ones described in (Maturana H., and Varela, F. 1987) and contextualized for systems design in (Winograd, T. and Flores, F., 1986). In this paper we discuss practical dimensions related with the integration of phy- signals in interactive systems. These dimensions were identified in simple experiences with EEG and ECG signals. The experiences were designed to demonstrate the value of this integration, but also to set up platforms that allow us to engineer coupled systems and applications. The next section provides a systematic overview of design and development issues that we encountered in our experiences. The following section briefly describes two samples applica- tions, which provide examples for the brief review of the design issues that follows. We con- clude with a summary of lessons learned so far and prospects for future designs.