Performance load is the amount of work, both mental and physical, a task requires in order to be completed. The chances of a task being completed to a sufficient standard decrease when the amount of effort required increases (Butler, Holden and Lidwell, 2003, p. 148). The mental effort required is known as the cognitive load, and the physical effort is kinematic load.
Cognitive load theory has led to the development of techniques that make information easier to remember (Sweller, 2011, p. 48). Cognitive load theory stresses the importance of working and long-term memory, and how knowledge of the memory types can lead to greater understanding of how to present information. If information is hard to read and unclear, or a page is poorly designed, there is less chance that it will be read and completely remembered (Erre, Ginns and Pitts, 2006). If a task isn’t complex, yet takes a long time to complete, it is said to have a high cognitive load (Ayres, Kalyuga and Sweller, 2011).
Butler, Holden and Lidwell (2003) mention that kinematic load is the amount of physical force required to complete a task. They don’t cover that this force differs between individuals, such as a disabled person needing to exert more to achieve the same goal.
Ayres, P., Kalyuga, S., & Sweller, J. (2011). Cognitive Load Theory. Australia: Springer.
Butler, J., Holden, K., & Lidwell, W. (2003). Performance Load. In Universal Principles of Design (pp. 148-149). Massachusetts: Rockport.
Erre, C., Ginns, P., & Pitts, C. (2006). Cognitive Load Theory and User Interface Design: Making Software Easy to Use. 2015, from http://www.ptg- global.com/PDFArticles/Cognitive%20load%20theory%20and%20user%20interface%20design%20Part%201%20v1.0.pdf
Sweller, J. (2011). Cognitive Load Theory. Psychology of Learning and Motivation, 55(1), 37-76.