On mental models, planning actions, affordances, and metaphors
From Usability to User Experience Pt. 2
(If you missed the first part you can catch up here 👉 https://bit.ly/2MxIeGt)
In this article I hope to make a little clarity on some of the key terms of usability theory, this article is the result of research and personal work, I hope it can be useful to you!
1) Mental Models
In discussing user actions, we talked about mental models an important concept in understanding the interaction between person-machine and, necessarily, designer. Mental models are patterns we have in our minds that represent the way we think things work. These representations are personal, people can build different mental models of the same object, on the contrary the functioning of the same object can be represented by multiple mental models in the memory of the individual user, who will recall them as needed. While speaking of mental models Norman specifies which are the other two elements that enter in game in the use of an object (or system) that is the model of the projects and the image of system.
The model of the project corresponds to the conceptual model of the planner and adheres to the real model of the operation of the object. The system image on the other hand is the overall image that the object gives including the instructions, external appearance, and other elements such as manuals and advertising.The designer in most cases can not communicate directly with the end user, for this reason it is important that the system image clearly communicates the design model, the designer must therefore ensure that its conceptual model is clear and understandable in the finished product.
The product will be successful (in terms of usability) if users are able to learn how it works with as little effort as possible. According to Clarisse De Souza, objects must not only communicate their use but must also communicate the conceptual models that underlie their conception (De Souza, 2005a), the system should lead to a homogeneity between the model of the designer and the user through a communicative exchange in which not only the user must reconstruct the correct model, but the designer must facilitate it by making it clear what he intends to communicate As the scholar argues in fact:
The system is thus the designer’s deputy-a communicating agent that can tell the designer’s message. Because the user communicates with the system, the designer’s deputy must of course have elaborate communicative capacities. It must be able to communicate the contents of the one-shot message, which includes communication about what it can do.
( De Souza, 2005 The Semiotic Engineering of Human-Computer Interaction, Cambridge, Mass, The MIT press)
Clarisse de Souza is a full professor at the Department of Computer Science at the Pontifical Catholic University of Rio de Janeiro, where she works on person-computer interaction and semiotics. She argues that in order to communicate their vision to users, designers must position themselves as legitimate interlocutors in the context of interactions between people and systems. Precisely because they are not present at the moment of interaction, they must speak through the system, which thus becomes the designer’s spokesperson.
2) Metaphors
A fundamental contribution to the concept of metaphor applied to usability is due to George Lakoff and Mark Johnson, who in the book “Metaphors we live by” they deepen the metaphorical nature of the conceptual system. The main thesis of the text is that the metaphor is an important mechanism not only in everyday language, but also in our cognitive functioning. According to the authors, the conceptual system is at the basis of our knowledge of the world and how we interact with it. The concepts help us to categorize reality and individual daily needs into known macro areas, thus elevating the conceptual system to an important element not only for thoughts but also for our actions:
Instead, we have found that metaphor is ubiquitous in everyday language, and not only in language but also in thought and action: our common conceptual system by which we think and act is essentially metaphorical in nature (Lakoff, Johnson).
This idea of metaphor is important in order to create a theory of usability because in it lies the notion that unknown programs and situations can be learned based on the exploitation of prior knowledge.
In design we call metaphors all those situations in which to name functions attributed to interface elements we refer to concrete objects that perform the same function in the real world.
The metaphors found on UIs are visual and consist in most cases of an icon (stylized configuration of visual signs) that for a variety of perceptual and conventional reasons represents a certain set of ordinary practices. This icon replaces the verbal description of the actions we want to take due to a similarity between the ordinary practices and the actions we do on the screen.
The metaphor of the recycle bin is one of the most well-known and used metaphors, the designer suggests to the user that in order to understand how the command “recycle bin” works, he can refer to his real experience with the object (therefore to the mental model of the recycle bin he already has) and proceed by similarity throwing away files and documents digitally as he would do in reality.
It is therefore essential for the designer to choose a model that is already part of the end user’s knowledge base so that the metaphor is effective.
Over the years, the most relevant criticism of the use of metaphors has come from Nielsen (1999), whose position has often been misrepresented as being much more drastic than it actually was. In fact, the author has always advocated the value of metaphor as a useful means of familiarizing users with a new environment, while emphasizing the need to be contradicted or transformed into standards as needed.
The greatest usability is achieved when users have become accustomed to an icon, a button, a designation, to immediately understand what it means what actions it implies and, what consequences it produces, forgetting its metaphorical origin (Jakob Nielsen, 1999).
3) Planning (an action)
Planning, as theorized in Norman, is part of that moment of action immediately following the definition of the purpose; it is the first step that will lead us to our goal. The process of planning is therefore placed within a program composed of various ordered steps. From the design point of view, these steps must be foreseen by the designer in order to be able to anticipate the user’s moves, also taking into account the fact that often not all actions are planned to the end but some users sketch only a first strategy of action and then redefine them in the process.
In research on human-computer interaction and in those on usability, the planning process is theoretically placed within a program consisting of a series of sequential steps ordered towards a goal. The action plan is not conceived as a static construction that is then realized in the action, but is subject to change and adjustment during the course of the action itself. Constraints and external contingencies in fact make the action a dynamic process in which the user must continually adapt his moves and goals to achieve a purpose. In order for the human-computer interaction to be optimal, it is necessary that both are able to interact at every step of the action in progress, it means that in every moment the user must be able to understand what consequences his actions have had on the course of the action in order to take the most appropriate decisions.
4) Affordances
The first psychologist to introduce the concept of affordance was J.J. Gibson who laid the foundations in the fifties, formalizing his theory in the text The ecological approach to visual perception in 1979. According to Gibson,
affordances are not only qualities belonging to the object, but must be seen in relation to the environmental niches of which the object is part.
The affordances that an object presents are therefore recognizable by the user only if the latter is moving in a familiar space. Among the scholars who have dedicated themselves to this topic, Donald Norman uses affordances as a means through which objects can communicate their usability in an intuitive way.
According to the author, the affordance of an object is a relationship that it immediately establishes with the user, thus giving to this element a primary role in the characteristics of usability. Often, however, communicated actions can be misleading, in recognizing this possibility Norman introduces the concept of perceived affordance, to address the plurality of possible interpretations, even misinterpretations, that can be made of the use of an object.
Perceived affordances are for Norman an expedient to obviate the questionability of the intuitive characteristics of affordances. As a last evolution of the concept of affordance Norman introduces also the term signifier meaning with this an element that communicates where the action is possible, the signifiers signal things, in particular which actions are possible and how to execute them. Signifiers must be perceptible otherwise they do not work.
Bibliography:
For this article, in addition to the already mentioned books and authors I used the book Design of everyday things By Donald Norman as a main source of information.
