Psychology of usability User interfaces Jaana Holvikivi EVTEK
Jan 19, 2016
Psychology of usability
User interfacesJaana Holvikivi
EVTEK
Usability goals
International Standards Organization ISO 9241 definition:
Usability is the effectiveness, efficiency, and satisfaction with which users can achieve tasks in a particular environment of a product. High usability means a system is easy to learn and remember; efficient, visually pleasing and fun to use; and quick to recover from errors.
Effectiveness: can users successfully achieve their objectives?
efficiency: how much effort and resource is expended in achieving those objectives?
satisfaction: was the experience satisfactory?
Universal usability
Variations in physical abilities, disabilities Variations in use environment Diverse cognitive abilities Diverse perceptual abilities (vision,
hearing) Personality differences Cultural and international diversity Special user groups: children and the
elderly
Related fields
Engineering psychology Ergonomics Experience design Human-centered computing Human computer interaction (HCI) Industrial Design Systems engineering Ubiquitous computing User-centered design User experience design
Ease to learn in interface design
Familiarity in interface Observations and patterns
regular shapes proximity continuity recognition grouping
Logical structure
Grouping
1. features- colors, size, shape
2. prototypes, schemas3. internal consistency & similarity
in a group4. logical, conform with reality5. sparse (not too many categories)
Regular shapes
vision / perceptions simplifies and groups things together 5 circles (not 9 parts)
Proximity
Similarity
Continuity
Familarity
Connectedness
Object - background
Balance
size color
dark colors heavy position
proximity
do these move?
Creating forms
Left-aligned Vertical alignment of texts Items that repeat in the same
position Chunking & grouping Regular size input fields
Grid for forms
Code:
Name:
12345 OK
Address:
A Company
Old countryroad
Esbo02650
Efficient dialogue
6..15 groups
neat layout use of space experienced user prefer dense
forms novices prefer less crowded boxes
Fastest spotting of items
Mediocre spotting of items
Human perception: sees patterns
People can discriminate color and lighting
Object and background Borders and continuity Shapes and interpretations People remember even large chunks Football teams: colored shirts
Shades
source of light concave and convex
Interpretation
Interpretation
Müller-Lyer -illusion
Background
Colors
Help in recognition Have emotional values and
symbolic meanings - warning Warmth Color blindness common
Background
Human cognitive capacity 1
Based on patterns and schemas Chess masters remember nearly all
pieces in a game Affordances: visual object is
perceived through intended action; perception depends on context
Auditive and visual input separate
Human cognitive capacity 2
Attention: selective perception Object and background: discrimination,
exceptional features Attention is directed to one object Memory registers also unconscious
perception Automatic actions (bicycle riding) do not
need attention; but then action becomes fixed, difficult to modify (changes in interface)
Mechanicalsenses: touch,
painBody state (hunger,
vestibular sensation, etc.)
Brain
Audition
Vision
Chemical senses:Smell, Taste
Stored experience:MemoryEmotions
Movement
Action
Working memory
Modalities: perception
MEMORY
Short term memoryLong term or Reference memory
Modalities
Precedural memoryDeclarativememory
Sensorymemory
Workingmemory
Centralexecutive
Motorskills
Perceptuallearning
ConditioningSemanticmemory
Episodicmemory
Habituation and sensitation
RecallRecognition