Human capacity to process information is limited by the capacity of the working memory. Overloading the working memory interferes with information processing. The Cognitive Load Theory (CLT) has been proposed as a framework to control and adjust the cognitive demands imposed upon an individual exposed to print materials or electronic materials accessible through complex digital environments. Hollender, Hoftmann, Deneke, & Schmitz (2010) identified three types of cognitive loads:
- Intrinsic cognitive load: The intrinsic complexity of the information to be processed;
- Extraneous cognitive load: The extraneous cognitive load is the result of being exposed to too much superficial information from various sources; as a result, the performer must devote considerable effort to extract and integrate the relevant information since “information from one source has to be maintained in working memory in order to integrate it with information from the other sources (Hollender, Hofmann, Deneke, & Schmitz, 2010, p. 1279) citing (Ayres & Sweller, 2005);
- Germane cognitive load: Cognitive load is increased when providing too much variation in work example (Hollender et al., 2010).
The ICT usability standard is designed to ascertain that a satisfied user can use the technology to perform a task effectively and efficiently. There are five common dimensions of usability: learnability, memorability, efficiency, low error rate, and user satisfaction. Over the years, User Experience has evolved as a more holistic concept of usability, which encapsulates four desirable dimensions for a digital tool: enjoyable, motivating, aesthetically pleasing, and supportive of creativity (Hollender et al., 2010).
Given the increasing use of technology for learning, the human-computer interface research focused on the learner as a user. The priority of HCI and learning is on learnability and the effectiveness and efficiency of technology-based instructional materials (Hollender et al., 2010). Instructional design and development efforts are directed to the adaptation of instructional materials to fit learners’ needs. The Aptitude by Treatment Interaction (ATI) research indicates that instructional treatments differ in the information processing demand they place on learners. A learner may fail to master an instructional task, simply because of a deficit in information processing skills (Chinien & Boutin, 1993). Instructions are often adapted to circumvent low ability learners on the basis of a fundamental assumption that learnability is improved as instruction takes over more of the information processing burden (Crono & Snow, 1986). Robertson (1985) has suggested that in order to achieve successful human-computer interface: “both the information-processing systems and the strategies used by the machine and also the cognitive systems and strategies deployed by human need to be appropriate” (Robertson, 1985, p. 19).
Technology and software engineers and researchers have for a long time realized the importance of human information processing for the human-computer interface:
“The major problems that confront users of advanced information technology are not legibility and keyboard design but instead concern information management, problem description, process representation and the like…that this interaction takes place through computers and their peripheral devices should not be allowed to obscure the fact that it is essentially cognitive and that the most important issues are cognitive” (Storrs, Rivers, & Canter, 1984, p. 62), cited by (Robertson, 1985, p.19).