Human performance Models and (lect2).ppt
- 1. Human performance Models • Idea: If we can build a model of how a user works, then we can predict how s/he will interact with the interface – Predictive model predictive evaluation
- 2. Human performance Models Perception. Cognitive. Mental . Communication and collaboration models
- 3. Human performance Models Perception:- An understanding of the way humans perceive visual information is important in the design of visual displays in computer systems. Several competing theories have been proposed to explain the way we see. These can be split into two classes: 1- constructivist . 2- ecological..
- 4. Perception:- • Constructivist theorists : believe that seeing is an active process in which our view is constructed from both information in the environment and from previously stored knowledge. • Perception involves the intervention of representations and memories. • What we see is not a replica or copy.
- 5. Perception:- • Perception:- is constructed by the visual system through 1- transforming, 2- enhancing, 3- distorting, 4- discarding information.
- 6. Ecological • Ecological : believe that perception is a process of ‘picking up” information from the environment, with no construction or elaboration needed. Users intentionally engage in activities that cause the necessary information to become apparent. We explore objects in the environment.
- 7. Perception:- Look at the following figure: What does it say? What do you notice about the middle letter of each word?
- 8. Perception:- proximity - how elements tend to be grouped together depending on their closeness.
- 9. Perception:- similarity - how items that are similar in some way tend to be grouped together. Similarity can be shape, colour, etc
- 10. Perception:- closure - how items are grouped together if they tend to complete a pattern.
- 11. Perception:- good continuation - we tend to assign objects to an entity that is defined by smooth lines or curves. Example
- 12. Perception:- Example in user interface design – proximity used to give structure in a form:
- 13. Perception:- • Influence of theories of perception on HCI • The constructivist and ecological theorists fundamentally disagree on the nature of perception. • However, interface and web designers should recognize that both theories can be useful in the design of interfaces.
- 14. Cognitive models. Cognitive Modeling Producing a computational model for how people perform tasks and solve problems, based on psychological principles. Cognitive models represent users of interactive systems.
- 15. Cognitive models More complex . Hierarchical. Hierarchical models represent a user's task and goal structure. Linguistic Linguistic models represent the user-system grammar. • TAG . • Task Action Grammar. • CLG - Command Language Grammar. Physical and device models represent human motor skills.
- 16. Mental Models Mental Models: Mental representations of how an object/system operates. Help us predict the outcomes of our actions. Help us identify and fix problems. Developed by experience (trial and error),training and feedback. Interaction with system should help user develop an accurate mental model of how the system works and what to expect.
- 17. Communication and collaboration models All computer systems, single user or multi-user, interact with the work-groups and organizations in which they are used. • We need to understand normal human-human communication: – face-to-face communication involves eyes, face and body – conversation can be analyzed to establish its detailed structure.
- 18. Communication and collaboration models • This can then be applied to text-based conversation, which has: – reduced feedback for confirmation – Less context to disambiguate utterances – slower pace of interaction • but is more easily reviewed.
- 19. Communication and collaboration models • Group working is more complex than that of a single person: – it is influenced by the physical environment – experiments are more difficult to control and record – field studies must take into account the social situation.