The strong programme of research in the study and development of cognitive technologies today is based on the hypothesis that these technologies are not only technical means which enable us to enhance our calculating, memorizing or perceptive abilities, but that they actually play a key role in the constitution of human experience. The aim of this article is to provide this hypothesis with experimental content through the study of a series of very specific technical devices usually referred to as `sensory substitution systems'. After analyzing some of the results achieved so far, we will describe several experiments on the construction of a three-dimensional perceptual space through technical means. We will then demonstrate the role of human action, and, therefore, of the `corps propre' (the body from the point of view of the subject), in the process of the construction of perception. These experiments will also enable us to discuss the conditions for conducting fundamental research in the field of technology, combining scientific method and phenomenological analysis. In conclusion we will suggest various possible lines of future research on this subject.