6. Theory and HCI Flashcards
How can theories of cognition help in interaction design?
Human abilities and limitations have important implications for interaction design and cognitive psychology can give us some insight into these.
Predictive uses - Gives us understanding of what users can and cannot be expected to do
Explanatory uses - Identifies and explains why users encounter problems
What is human cognition?
All forms of knowing and awareness such as perceiving, remembering, reasoning, judging and problem solving
What are design implications for the cognitive process Vision? (5)
Simple layouts
Visual structure (law of similarity)
Visual flow (law of continuity)
Be consistent (e.g fonts, navigation)
Colour is useful but don’t rely on it alone!
What are the 3 types of memory?
Sensory memory - specific to the senses, holds information for a very brief period of time
Working memory - Limited capacity to hold current information, decays quickly
Long term memory - Permanent storage of information with unlimited capacity. Slow decay
What are design implications for the cognitive process Working Memory? (3)
Reduce working memory load by:
Temporary information - Don’t expect users to remember lots of temporary information. Working memory holds limited amount of information
Multitasking - Don’t expect users to be able to deal with lots of different information at the same time. Interference can damage working memory
Chunking - Help users chunk information in working memory by presenting data in ways that make patterns clear - sort, order, group information
What is “chunking”?
The process of grouping information together (to increase working memory capacity)
e.g. the telephone number 020-7040-8000 is easier to remember than the string of digits 02070408000
Experiments suggest that its capacity is 7 +/- 2 chunks of information, where a chunk is a meaningful group of smaller items of information
What are design implications for the cognitive process Long term Memory? (3)
Recognition over recall - Users will have to recall most gesture-based interactions whereas GUIs require recognition of visual items
Memorisation - Facilitate memorisation by using meaningful items at the interface e.g. by structuring information to help chunking
Offload information - Support the with an “external memory” to remember information for users
What are design implications for the cognitive process Attention? (4)
Avoid distractions and clutter - Attention is selective
Visual flow - Guide user’s attention to relevant information - e.g. use colour and structure
Problem solving - Engage users in problem solving. Complex tasks hold attention better than mundane ones. Humans are bad at monitoring tasks
Breaks - Provide breakpoints in lengthy tasks
What is “cognitive load”?
Cognitive load is the amount of mental resources required to operate and understand a system
What are the 2 subtypes of cognitive load?
Intrinsic cognitive load - inherent difficulty of completing a task
Extraneous cognitive load - Anything else taking up a user’s mental resources that is not directly related to the task
What increases cognitive load for users? (6)
Visual clutter
Distractions/ interruptions
Information/ choice overload
Stress / fatigue
Task complexity
Unfamiliarity / Limited prior knowledge
How can we reduce cognitive load? (6)
Be consistent and predictable - Reuse common user interface design patterns
Keep things simple - Avoid/remove clutter e.g. redundant links and images that slow users down. Eliminate unnecessary steps
Offload tasks - are there any steps that can be handled by the system itself to relieve the user?
Minimise choices - To avoid decision paralysis
Recognition rather than recall
Chunk content
What are “mental models”?
Mental models are representations of the world that people construct in their minds to help them understand how things work
What are some issues with mental models and UX?
Mental models vary and can change (Chan) - difficult to design for all
Norman - “Many people tend to have incomplete and unstable mental models of systems”
Mismatch - Leads to interaction problems
Designers vs users - Will have different mental models
What are Norman’s 3 mental models for interaction design?
Design model - Designer’s conception of the the product
System model - What has been created
User’s model - User’s conception of the model from interacting with the system
