Performance Load

Examples of Performance Load

The performance load of an object is how mentally and physically easy it is to use. Here are some examples of the performance load from everyday items from my life.

Example 1: Broom


This is an obvious example of performance load changing how commonly an item is used. Since the creation of the much less  physically intensive vacuum cleaner the broom is used much less often.

Example 2: Simple Weather Station


Rather than going out to set up and read something like a rain gauge, this weather station sends its automatic information to a screen in another location. The job is much easier and so likely to be used by at home weather men.

Example 3: Peeler


A peeler as simple as this one requires little cognitive load, especially compared to something like a knife. They are commonplace in kitchens for such a reason.


Psychology in Design

I believe that psychology is one of the most important parts of design. The very basis of designing a successful system or product relies on audiences gaining something from it. Because audiences are a primary focus, the way audiences think should always be taken into consideration. This allows for conventions and knowledge to go into a design that will help with the designer’s intentions.

Performance load is the perfect example of this. When people are faced with problems in a system that takes too long to be worth the effort, they give up on it. However if a designer were to make this system easy a person is much more likely to use it. This is just scratching the surface of psychology in design, but things that appeal to the human mind will always be used over things that don’t.


Chunking is the approach of breaking down information in order for the brain to more easily process new information. Human working memory can only hold a limited amount of information and so splitting it up assists in holding more. When several factors must be kept in mind at the same time, chunking becomes very useful.

When George Miller pioneered research into working memory capacity, a number around 7 (now believed to be closer to 5) was thought to be the limit of think humans can remember with breaking up information being a good memorization technique. The concept of “chunking” came heavily from William Chase and Herbert Simon’s article Perception in chess. Their study showed that chess masters are more likely to remember chess board layouts than novices use to their ability to organise what they know of the game. They used the term “chunk” to describe this organisational process.

Chunking can be applied to many more areas than just chess however. The challenge for a designer in holding an audiences’ attention through sometimes complex systems can lead to a high performance load. To avoid this chunking can be applied to designs. A basic example of this comes from phone numbers, which often are chunked into smaller bits to remember easily. Chunking can also work in nonlinear ways to group together information that is conceptually related.

However it should be noted that chunking information is not a perfect technique in every situation of design. When searching, scanning or analysing information only particular things need to be memorized, so chunking would be pointless. Also chunking should not be used in every aspect of especially simple design (such as basic lists). When used properly though, chunking can certainly lighten the performance load.



Chase, W. G., & Simon, H. A. (1973). Perception in chess. Cognitive psychology, 4(1), 55-81.

Harrod, M. (n.d.). Chunking. Retrieved from Interaction design foundation:

Malamed, C. (2009). Chunking information for instructional design. Retrieved from The eLearning coach:

Miller, G. A. (1956). The magical number seven, plus or minus two: Some limits on our capacity for processing information. Retrieved from The music animation machine:

Performance Load

To put it simply performance load is “the degree of mental and physical activity required to achieve a goal” (Lidwell, Holden, & Butler, 2010). The higher the performance load, the higher the performance time and chance for errors. Cognitive load is used to refer to the amount of mental activity and kinematic load to physical activity.

George A. Miller was the first to suggest limits in in human working memory capacity. His article The Magical Number Seven, Plus or Minus Two introduced the idea of average human memory holding only a number of objects (7 ± 2) in their working memory.

John Sweller developed the theory of cognitive load “to provide guidelines intended to assist in the presentation of information in a manner that encourages learner activities that optimize intellectual performance” (Sweller, Merrienboer, & Paas, 1998). From these theories ideas to help lighten the cognative load like “chunking” was developed.

These psychological aspects can of course also be implanted in not only a kinematic way, but also into designs. Because of mental and physical limitations, people will only put up with so much performance load before errors and time consumption force them to abandon.



Lidwell, W., Holden, K., & Butler, J. (2010). Universal principles of design, revised and updated. Minneapolis, Minnesota: Rockport Publishers.

Malamed, C. (2009). Chunking information for instructional design. Retrieved from The eLearning coach:

Miller, G. A. (1956). The magical number seven, plus or minus two: Some limits on our capacity for processing information. Retrieved from The music animation machine:

Sweller, J., Merrienboer, J. J., & Paas, F. G. (1998). Cognitive architecture and instructional design. Educational psychology review, 10(3), 251-296.