What is cognitive load?
Cognitive Load Theory, first developed by educational psychologist John Sweller in 1988, suggests that our working memory is only able to hold a small amount of information. The working is a cognitive system with limited capacity that can hold information temporarily and it is important for reasoning and guidance of decision-making. This theory is commonly applied in instructional methods to avoid overloading learners in order to maximise learning.
In the field of UX, cognitive load is defined as the amount of mental resources required to operate the system. When users use a digital product, they tend to have a goal in mind. They have to learn how to navigate the website in order to find what they are looking for. Even if the website is familiar to them, they still have to hold information that is relevant to their goal.
There are 2 different types of cognitive load:
- Intrinsic cognitive load refers to the fundamental difficulty of a specific topic, regardless of how that topic is presented. Intrinsic cognitive load is dependent on a user’s prior knowledge of the subject matter and it is not possible to eliminate across users.
- Extraneous cognitive load refers to the load generated by the way information is presented. Extraneous cognitive load can be reduced with good content writing and applying usability guidelines.
Minimising Cognitive Load
- Present content in a way that is easy to read and understand
In a previous article, I wrote about how people read on the web. The fundamental truth is that people do not read word for word, they scan to look for keywords that will point them to what they are looking for. When writing for the web, UX writers should start with the question: what does the user want to know?
Meeting that need means to be specific, informative, clear and to the point.
Good content is easy to read and understand. It uses
- short sentences
- sub-headed sections
- simple vocabulary
We can also look at applying instructional design methods to organise the content in a way that is easy to read and understand.
Sequencing is the efficient ordering of content in order to improve the learner’s understanding. There are several methods of sequencing — Content can be sequenced from easy to difficult, simple to complex, general to specific.
Chunking is a way of organising information into meaningful and bite-sized units in order to make more efficient use of our working memory. Psychologist George Miller found that the maximum quantity of ideas, facts or issues that people are able to actively attend to at any one time is 7 (plus or minus 2). Cognitive load increases when more content is introduced.
Commonly used methods of chunking includes:
- Using short paragraphs
- Having short lines of text
- Establish clear visual hierarchy with related items grouped together
2. Reducing memory load by promoting recognition
Recognition rather than recall, one of Jakob Nielsen’s 10 usability heuristics, is a method for minimising the user’s memory load by making elements, actions and options visible. As the working memory is able to hold a limited amount of information, users should not be made to remember information from one part of the interface to another.
Design practices to promote recognition include:
- Making field labels or menu items visible or easily retrievable when needed
- Providing users with a step-by-step tutorial in context, rather than making them read through a long tutorial document
- Lengthy forms should be compacted to fit a single display
- Using familiar design patterns that fit users’ mental models. For example, users would have a mental model of how an airline booking website looks and the steps taken to book a flight ticket. Their cognitive load increases if they encounter a website that works differently from what they have in mind.
3. Redundancy principle
In instructional design, the redundancy principle suggests that redundant material interferes with rather than facilitates learning. Redundancy occurs when the same information is presented concurrently in multiple forms or unnecessarily elaborated. Coordinating redundant information increases cognitive load.
In UX design, avoid visual clutter that does not contribute to the user experience by removing redundant links, irrelevant images and distracting animations.
4. Eliminating unnecessary tasks
Finally, cognitive load can be minimised by eliminate unnecessary tasks that do not contribute to user goals. This can be done through a task analysis which is the process of understanding in detail how users perform their goals and achieve their intended goals. It helps to identify the tasks that the product must support.
