In this blog post I will be providing a summary of an excerpt titled Performance Load (Lidwell, Holden & Butler, 2003, pp 148-149) and a critical analysis of the topics raised within the text.
Lidwell et al. describe performance load as the amount of mental and physical activity required to carry out a procedure. A higher performance load results in tasks taking longer with a larger chance of errors, while lowered performance load shortens task time, lessens chance of errors and increases a user’s potential to reach their desired goal. Lidwell et al. outline Cognitive Load as the brain’s mental capacity to learn, memorise and problem solve on any given task. As the working brain is “quite vulnerable to overload” (What is cognitive load? n.d.), designers must simplify user interfaces and reduce cognitive load with memory aids, information chunking and navigation tools. Paas, Renkl & Sweller (2003) believe that displaying too much information on a website or interface can significantly reduce the user’s capability and will decrease their chances of returning to the site again.
The second kind of performance load is Kinematic Load and it describes the amount of movement, force and general physical activity required to carry out a task (Lidwell et al.). The evolution of technology has allowed devices and systems to be streamlined so that less physical action is required to operate certain products. Lidwell et al. underline the inventions of Morse code, central locking and card-operated casino slot machines as some ways to reduce human movement. In a book titled Design process improvement: A review of current practice it is said that kinematic load should match the physical capabilities of the user. Therefore, products designed for handicapped users should significantly reduce movement and effort needed to reach a goal (Clarkson & Eckert, 2004).
While organising and structuring the vast amounts of information on Web pages can be challenging, performance load must be minimized to the “greatest degree possible” (Lidwell et al.). This convention is supported by a Stanford University study which found that simple and correct layout and instructions can lower human error by 50% (Stanford University, 2007).
- Lidwell, W., Holden, K., & Butler, J. (2003). Aesthetic- Usability Effect. In Universal Principles of Design(pp. 18-19), Massachusetts: Rockport.
- Paas, F., Renkl, A., & Sweller, J. (2003). Cognitive Load Theory: A Special Issue of Educational Psychologist. New Jersey, United States: Lawrence Erlbaum Associates Inc.
- Clarkson, J., & Eckert, C. (2004). Design process improvement: A review of current practice. London: Springer.
- Identification and validation of cognitive design principles for automated generation of assembly instructions. [n.d.]. Retrieved from http://graphics.stanford.edu/papers/assembly_instructions_study/
- What is Cognitive Load? [n.d.]. Retrieved from http://theelearningcoach.com/learning/what-is-cognitive-load/