Hi Francesca, 

Your questions are very interesting. I would like to see how they develop. In my dissertation research, I am looking into the communicative efficacy of appeals to emotion, reason, and character. This ‘triangle’ is similar to the one you are posing. However, my current interest is in visual communication design for individuals with limited functional literacy.

I started my investigation, in part, from the theory of rhetoric, which would be useful for you too, I think. You should read carefully works of Buchanan (1985; 1995), in which he discussed design as rhetoric. Particularly in the rhetorical appeals, he defined the design ‘logos’ as technological reasoning, in which products communicate how they address technological viability and practical circumstances of use. Design ‘pathos’ is the emotion and desire element, in which the designed object reaches the level of fine art but for practical purposes. Design ‘ethos’ is the character and credibility reflected by the creator or manufacturer, which provide persuasion about the values of products and give confidence to users. Buchanan has also analyzed these appeals in everyday objects.

While the theory of rhetoric differentiates among these three appeals, the theory also provides a framework to see them integrated in the arguments that are embodied in the design artifact. A good designer (or rhetorician) should forethink how the artifact will appeal to emotion, reason, and character. And if a dominance of a particular appeal is needed.

Hope this helps.

G. Mauricio Mejía
Assistant professor University of Caldas
PhD in Design Student University of Minnesota

Buchanan, R. (1985). Declaration by Design: Rhetoric, Argument, and Demonstration in Design Practice. Design Issues , 2 (1), 4-22.
Buchanan, R. (1995). Rhetoric, humanism, and design. In R. Buchanan, & V. Margolin, Discovering design (pp. 23-66). Chicago, IL: The University of Chicago Press.