Metaphor Interface

A cognitive load approach to metaphorical interface design: Reconsidering theoretical frameworks Jongpil Cheon Instructional Design and Technology University of Memphis United States [email protected] Michael M. Grant Instructional Design and Technology University of Memphis United States [email protected] Abstract: This paper presents theoretical foundations to investigate in what ways a metaphorical interface in Web-based instruction affects learning in terms of cognitive load. The previous study by the authors revealed there were no significant differences among three interface types. To ground a follow-up study, new theoretical frameworks of metaphorical interface and cognitive load are presented followed by implications for the future study. This paper explores systematic uses of a metaphorical interface and relationships between the functions of metaphorical interfaces and cognitive load types. In addition, the implications for the future study are proposed. Introduction A functional, communicative and aesthetically appropriate user interface plays an important role in helping learners focus on learning activities. An effective interface should be intuitive and facilitate communication between learners and instruction by cultivating learning rather than operating an instructional unit (Haag & Snetsigner, 1993; Metros & Hedberg, 2002). However, designing a usable and appealing interface is still challenging for instructional designers. For example, the user interface portion of the software accounts for over half of the code and development time (Chalmers, 2003; Myers, 1998). In order to implement an effective user interface, interface guidelines and considerations have been introduced based on graphic design rules, human cognition and usability (Cheon & Grant, in press). Our previous research focused on the effects of three different interface types (i.e., textbased, graphical and metaphorical interfaces) on performance, cognitive load, usability and appeal. There were no significant differences except with appeal. This proposal extends the previous study. The purpose of this study is to investigate relationships between a metaphorical interface and two different cognitive load types (germane and extraneous cognitive load). To achieve the research purpose, we reconsider the assumption with established

cognitive load research methods and measures, and present future research plans. Metaphorical interface What is a metaphorical interface? A metaphorical interface design employs a visually underlying metaphor related to the instructional contents within an entire Web environment (Cates, 1996; Hron, 1998; Hsu & Boling, 2007). A metaphorical interface conveys rich images and other types of multimedia holding more meaning than the literal definitions (Berkley & Cates, 1996) so that the users can assimilate new knowledge into existing schemata (Ohl & Cates, 1997). Studies defined different types of a metaphorical interface based on several perspectives: (a) an integral and a composite metaphorical interfaces based on the number of metaphors (Hsu & Boling, 2007), and (b) a mixed, thematic and immersive metaphorical interfaces based on the depth of metaphors used (Cates, 1996). Cates (1996,

2002) also defined two components of a metaphorical interface: (a) an underlying metaphor employed as a basis, and (b) an auxiliary metaphor employed later to extend and complement the underlying metaphor. In this proposal, the metaphorical interface can be classified into two different types depending on the way metaphors are employed: (a) a thematic and (b) an immersive metaphorical interface. A thematic metaphorical interface uses a metaphorical theme that does not exactly reflect the contents, but the theme is familiar with learners, such as a book or a folder on the computer screen. On the other hand, an immersive metaphorical interface builds an authentic environment that reflects learning contents with structural cues or organizational hints. What are the advantages of a metaphorical interface? Based on the relationship between a metaphorical theme and learning content, learners can intuitively interact with instructional resources to organize knowledge schema (Allbritton, 1995; Cates, 1996; Hron, 1998; Lang, 2003; Metro & Hedberg, 2002) and develop mental models (Cates & Berkley, 2000). Since the metaphorical environment allows the user to gain insight about unfamiliar learning content, it can decrease learners� cognitive load related to interfaces and disorientation (Hron, 1998; Ohl & Cates, 1997). For example, a metaphor offers novice users a safe and familiar environment to explore learning contents (Cates & Berkley, 2000). How should we choose appropriate metaphors? Although previous research asserted many promises of a metaphorical interface, selecting appropriate metaphors and determining how to apply it are still challenging for instructional designers (Cates, 2002; Ohl & Cates, 1997). Inappropriate metaphors that mismatch a relationship or representation of learning contents could lead to incorrect inferences (Barr et al., 2002; Hamilton, 2000; Hsu & Boling, 2007). The design guidelines for a metaphorical interface are categorized as follows: � Metaphors should be related to learning contents and provide adequate clues to users (Hsu & Boling, 2007; Hudson, 2000) � Metaphors should represent the system structure such as information sequence (Barr et al., 2002; Hron, 1998; Hsu & Boling, 2007; Hudson, 2000) � Metaphors should support learning strategies (Hron, 1998) � Learning environment and navigation and learning contents should be closely interrelated (Hron, 1998)

� Metaphors should provide not only their appearance but also their action (Hsu & Boling, 2007; Hudson, 2000) � Metaphors should consider learner�s age and culture (Hudson, 2000; Ohl, & Cates, 1997) Effects of a metaphorical interface on learning The theories and research mentioned in the previous section argued that interactions with metaphorical interfaces could either enhance or impede learning. Effectiveness of interfaces has been measured by three perspectives: learning performance, cognitive load and usability (Cheon & Grant, in press). However, few studies have examined the effectiveness of a metaphorical interface. Hsu and Schwen (2003) found that searching performance was better with a composite metaphorical interface. In addition, a subsequent study showed that a metaphor-rich interface facilitated experts� searching better than novices� searching (Hsu, 2005). This finding opposes Cates�s (2002) argument that a metaphor helps particularly novice users. On the other hand, Cates and Berkley (2000) found no significant differences in terms of the effectiveness of instruction between a metaphorical design and an equivalent thematic version. In addition to learning performance metaphorical interface�s effects on cognitive load should be considered. Cognitive load theory The functions of a metaphorical interface have been emphasized by scholars from a cognitive perspective (e.g., Allbritton, 1995; Hamiltion, 2000; Ohl & Cates, 19997). For example, an important function of metaphors is providing the learner with a coherent framework and schema for understanding complex domains (Allbritton, 1995). In addition, Ohl and Cates (1997) asserted that a metaphor could be a cognitive aid to the user, and it could enhance the usability of the interface. The cognitive aid with a structural cue and usability is closely related to cognitive load

theory. In order to measure these potential functions of a metaphorical interface, cognitive theory should be applied to empirical research. Proponents of cognitive load theory argued that working memory is limited (Sweller & Chandler, 1994). Cognitive load theory strives to capture the learner�s focus by preventing the learner�s capacity from overloading (Vogt, 2001). Cognitive load theory distinguishes three types of cognitive load: (a) intrinsic cognitive load affected by the intrinsic nature of the learning tasks themselves; (b) extraneous cognitive load affected by the manner in which the tasks are presented; and (c) germane cognitive load that is the amount of cognitive resources that learners willingly invest in schema construction and automation (Sweller & van Merrienboer, 1998). The three types of cognitive load are additive, and both extraneous and germane load are under the direct control of instructional designers (Paas, Tuovinen, Tabbers & Van Gerven, 2003). Therefore, the primary implication for instruction is to decrease extraneous cognitive load and to increase germane cognitive load within the limits of available processing capacity (van Merrienboer & Ayres, 2005). If the limits of human cognitive capacity are ignored, a Web-based instructional unit can actually interfere with learning even though it has many multimedia resources (Clark & Mayer, 2003). We posit that extraneous cognitive load is closely related to usability. Usability studies evaluate online learning functions for minimal amounts of user frustration, time, and effort (Nielson, 2000; Pearrow, 2007). A welldesigned interface should inform users what the objects on the screen stand for and how they work (Sing & DerThanq, 2004). Therefore, high usability means low extraneous cognitive load. Moreover, the structural and procedural cues in a metaphorical interface are related to germane cognitive load. Easily understandable structures given by a metaphor could enhance students� automation for connecting their existing schemata. Research findings with cognitive load Cognitive load research has focused on two variables: learner performance and learner mental effort. High learning efficiency occurs when learner performance is higher than learner mental effort (Tuovinen & Paas, 2004). Efficiency metrics have been used to quantify the efficiency of an instructional product (e.g., Kalyuga & Sweller, 2005; Paas, Tuovinen, van Merrienboer & Darabi, 2005; Paas & van Merrienboer, 1993). For example, Paas and van Merrienboer (1993) suggested that instructional condition efficiency could be measured by a standardized z-score for mental effort and a z-score for performance. In Kalyuga and Sweller�s study to examine the efficiency of an adaptive learning system, the mental effort rating of tasks was combined with the performance scores of the same

tasks to provide a cognitive efficiency indicator. Cheon and Grant (in press) conducted an interface study with three different types of interfaces. The findings showed that there were no differences among the groups in terms of mental efforts and time to completion. In addition to the two variables, a learning efficiency score was compared. Although a graphical interface had the highest efficiency score, there was no significant difference. The study failed to demonstrate the superiority of both graphical interface and metaphorical interfaces to a text-based interface except in appeal. Future research The next step is a systematic inquiry into the effects of a metaphorical interface on cognitive load through implementing a theory-based metaphorical interface, developing logical data collection methods, and conducting thorough data analysis. Research questions The main question of the future study is derived from Cates�s (2002) question that is how to determine if a metaphorical interface interacts in ways that contribute to the effectiveness of learning. The theoretical frameworks for cognitive load led to cognitivist ways of measuring effectiveness of metaphorical interfaces. However, the operationalization of mental effort from previous studies has not been clear. For example, mental effort could be attributed to germane cognitive load because users use their mental effort to build their own mental model. Or, the measure of mental effort seems to indicate intrinsic cognitive load, because researchers asked participants only to rate the difficulty of the instruction. The relationship between usability and extraneous cognitive load should also be considered. An interface with higher usability could have a higher possibility of producing lower extraneous cognitive load. Interface design may also have the added responsibility of being useful to both novice and expert users without alienating either.

Therefore, it is important to gauge users� germane and extraneous cognitive load to investigate a metaphorical interface�s roles with research questions: (a) Does a metaphorical interface affect learners� cognitive load types? (b) Are there any differences in germane or extraneous cognitive load with metaphorical and graphical interface? (c) What are the effects of a metaphorical interface on novice and experts? Possible methodologies The research methods could be built from the theoretical frameworks and suggestions from the previous study. For example, a more realistic metaphorical interface within a concrete domain, such as Biology or Architecture, needs to be implemented following the design guidelines of metaphorical interfaces. Also, developing both a graphical interface and a metaphorical interface with the same learning contents would offer an opportunity to compare the effectiveness of different types of interfaces. In addition, a larger sample would enhance the credibility of the findings of the future study. The most important data source is isolating the different types of cognitive load. Few studies developed practical methods to gauge germane and extraneous cognitive load and the definition of mental effort remains ambiguous. Although extraneous cognitive load could be measured by usability test items, it would be challenging to measure users� germane cognitive load. So, we are considering ways to incorporate prior knowledge with mental effort to produce a standardize score to represent intrinsic cognitive load with the remainder attributed to germane cognitive load. Summary To conduct a precise investigation of the effectiveness of a metaphorical interface, an in-depth review was presented. We defined a metaphorical interface, described advantages, and classified guidelines for implementing a metaphorical interface. In addition, three types of cognitive load were characterized, relationships between cognitive load theory and metaphorical interface were considered and suggestions for future study were stated. Based on the implications, a subsequent study will be conducted, and further explanation about implementation and findings will be provided in the presentation. References ACM Special Interest Group on Computer-Human Interaction Curriculum Development Group. (2004). Curricula for humancomputer interaction. Retrieved November, 24, 2006 from http://sigchi.org/cdg/index.html Allbritton, D. W. (1995). When metaphors function as schemas: Some cognitive

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