The purpose of this paper is to address the issue of the borrowing of scientific knowledge from different academic disciplines into computer science, a process known as "conceptual borrowing"[13]. This issue will be discussed using the example of emotion recognition and companion systems, as well as affective computing in general. Conceptual borrowing is a common phenomenon in scientific work, but it should be ensured, especially in sensitive research areas such as 'affective computing', that knowledge from other disciplines is adequately adopted and that this is reflected through regular feedback with the respective discipline from which knowledge originates. A central question addressed is what kind of scientific knowledge about emotions is required to develop systems that interact with individuals as if they possess the capacity to recognize, interpret, and respond appropriately to emotions. In addition, a research prototype from the domain of affective computing is presented and evaluated with respect to its development methodology.