The Metaphor of the Face as an Interface for Communicating Non-Quantitative Information

In this paper we propose that a metaphor can be used to represent domains that are not easily quantifiable. Formal representation of the metaphor then can be used as an interface to communicate information about those domains between the human and the computer at a cognitive and visual level. We propose a model, which uses the metaphor of a human face as an interface data formatting system for the perception and evaluation of universal aesthetics. 1. Metaphors computers live by The title of the introductory section is an adaptation of the title of the seminal work by Lakoff and Johnson (1980), where metaphors depict incomplete parallels between dissimilar ideas or things, emphasising some qualities and suppressing others. For more than two millennia, the metaphor has appealed to scholars interested in language, rhetoric and poetry. In the past few decades, the interest in formal theories of metaphor, which established relationships between its structure, functionality and cognitive nature, has increased in several disciplines including linguistics, philosophy, psychology, education and sciences, and has given birth to the contemporary theory of metaphor (Yu, 1998). The power of the metaphor has also been employed in the area of human-computer interaction (HCI) and interface design. A popular example is the desktop metaphor proposed by Xerox and popularised by the MacOS operating system. The desktop metaphor takes the office desk as a cognitive and visual framework for organising files on a computer. An icon of a sheet of paper is used to represent a file; icons of folders are used to group computer files together; and an icon of a waste-paper basket is used to dispose of unwanted files. The desktop metaphor is a conceptual and associative metaphor. Another example of a metaphor in interface design is the “virtual instrument”, which was developed to represent a measure of a particular type of physical value. A visual representation of a sound mixer, for example, is used as a metaphor for adjusting the volume of different media channels. The virtual instrument not only provides conceptual and associative information, it also provides a representation of quantifiable information. Although there is a substantial amount of work about the use of metaphor in interface design, there is still a lack of formalisms and formal approaches in this area. Kuhn et al. (1991) attempted to develop an algebraic approach to the problem, but this approach has not been elaborated. More fruitful research has been conducted by Anderson et al. (1994), who proposed the so-called “pragmatic model” of metaphor mapping based on a representation of the metaphor as a set of features. Anderson et al. defined four groups of features to describe metaphor mapping, which we present in terms of interface design: • features in the interface, which are supported by the selected metaphor; Authorized licensed use limited to: Murdoch University. Downloaded on November 10, 2009 at 01:20 from IEEE Xplore. Restrictions apply. • features in the interface, which are not supported by the metaphor; • features that exist in the metaphor, but are not supported by the interface; • features that neither exist in the metaphor nor are supported by the interface. The first two groups of features have been used by Anderson et al. to investigate the effectiveness of a metaphor in an interface. Defining the last group of features may cause some difficulties. Alty and Knott (1999) offer an interesting formalism, which extends the feature-based model of Anderson et al. to examine relationships, where the “tenor” (the original idea) is transformed (modified) by another idea called “vehicle”. Their analysis attempts to cover both system functionality and corresponding interface features. However, Alty and Knott provide neither guidelines for nor examples of how the proposed model-based approach can be implemented. They emphasize that there may be differences between the designer’s view of the metaphor and the user’s understanding of the same metaphor, which results in difficulties in the interface design. Alty and Knott do not provide a mechanism that guarantees the match between the two views of the same metaphor they assume that the designer’s view and the user’s view agree. While metaphors such as the sound mixer are able to communicate quantifiable information, the use of metaphors for perceiving and evaluating nonquantifiable information is much more problematic. The perception of aesthetics, for example, depends on non-quantifiable factors such as culture, skill and experience, to name but a few. The evaluation of aesthetics is even more problematic. The evaluation is generally left to humans who use a variety of subjective scales that are open to the human failings of error and individual bias. Because computers work with numbers, we need to convert an evaluation category to a number (e.g. “4” on a Likert scale of 1 to 5) in order to communicate with the computer. Usually there are some vague criteria. It is not clear what are the mechanisms of this conversion, i.e. it is usually difficult to formulate precisely why we give “4” for that evaluation category instead of “5” or “2”, as shown in Figure 1. Figure 1. Evaluating the originality of a design In this paper we propose that consistently formalised metaphor can be used to represent domains that are not easily quantifiable, such as the perception and evaluation of aesthetics. The framework proposed in this paper is based on the idea of visualising instances of metaphors that share configurations, which means that the metaphors have identical basic parts in the same basic arrangement. The instances of such metaphors form an interface between human and computer with which the human is able to communicate ill-defined categories to the computer for processing. The human face is an example of such metaphor. We propose a framework, which uses the metaphor of a face as a computer interface to communicate non-quantitative information between the human and the computer at a cognitive and visual level. In this case the conversion into numbers remains on the side of the computer. The computational representation of the metaphor provides the basis for comparison between different instances of the same metaphor. In the next section we briefly discuss the issues in communicating aesthetics in human computer interactions.