Friday, 30 January 2009

Cognitive Modelling: Norman's 'Designer's Model'

Currently I am reading About Face 3 (Cooper et al.). In chapter 2 it deals with the existing position, dictated by software, of humans having to understand how computers 'logically' behave. Interaction design aims to rebalance digital products in favour of the human rather than the machine. By facilitating clearer cognitive behavioural understanding in the user, interactions can be made more beneficial to the user. Where this chapter really begins to become useful is in its explanation of conceptual models in order to visualise how humans and computers work.

The first model Donald Norman refers to as the system model. This is the cognitive model that explains the processing structure of the code. About Face 3 prefers to refer to it as the implementation model.

How code processes its actions and how human beings believe a computer/device/machine works are not the same. The human's mental model of how it works can be simplistic, counter-intuitive, fanciful, inaccurate, illogical; but as long as it helps the human successfully use their computer/device/machine it doesn't matter to them. Where a lot of problems arise within interactivity is the chasm that can form because these two mental models are representationally different. One is a mapping of actual processes - 'implementation', the other is purely notional - 'explanation'.

To interface between 'implementation' and 'explanation' a third model arises, a model that Donald Norman refers to as the designer's model, and Cooper et al refers to as a represented model. A designer's model that maps closer to a system/implementation model maybe more 'accurate' to the actual mechanics of processing, but is cognitively problematic to human users [A in diagram].

A successful interface is one where a user can see how their "goals and needs can be met" (Cooper et al, 2007, p32). This is achieved through making the designer's model follow as closely as possible the users' perceptions of how they believe they access the content [C in diagram].

There is nothing ground-breaking here in regard to interaction design, but it is the first time I have come across these definitions. I have known of the butler metaphor (Isaacs & Walendowski, 2002) but Cooper and Norman's models give it a more theoretical depth. Below is an expansion of the diagram in About Face 3 on page 30, with my annotations that link it back to my recent paper on the location of the graphic designer in GUI design.

Norman's designer's model and Cooper et al's similar represented model helps to give a cognitive psychological and theoretical base to the role that underpins the work of interface designers. In my paper I wrote about and cited Gillian Crampton Smith, former school director of Interaction Design Institute Ivrea. She sees the "graphic designers’ role as more involved in the interactive design process 'designing what a package is and what it does, and then designing what it will be like' (Aymer, 2001a, p33)". Graphic designers as part of their practice alternate between the “consideration of objective information and intuitive leaps” (Frascara, 2006, p32) in order to arrive at successful visual solutions. Graphic design, when performed well, can “inspire a behavourial change” in its audiences (Forlizzi & Lebbon, 2006, p53). These three points I raised and discussed in my paper can now also be assessed within the framework of the designer's model, and how effective are visual solutions when measured against the user's mental models.


AYMER, G. (2001)a Norman Cooking. Create Online. 8. p38-40

COOPER, A., REIMAN, R. and CRONIN, D. (2007) About Face 3: The Essentials of Interaction Design. Indianapolis: Wiley Publishing Inc.

FRASCARA, J. (2006) Graphic Design: Fine Art or Social Science. In: A. BENNETT, ed. Design Studies: Theory and Research in Graphic Design - A Reader. New York: Princeton Architectural Press, p26-35

FORLIZZI, J. and LEBBON, C. (2006) From Formalism to Social Significance in Communication Design. In: A. BENNETT, ed. Design Studies: Theory and Research in Graphic Design - A Reader. New York: Princeton Architectural Press, p51-63

ISAACS, E. & WALENDOWSKI, A. (2002)Designing from Both Sides of the Screen: How Designers and Engineers Can Collaborate to Build Cooperative Technology. New Riders Publishing

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