chapter7

toc =Complex User Interaction=

Embodied interaction: The design of technology that recognizes the role and importance of the body. Two perspectives of embodied interaction: - Ergonomics (term coined in 1948) - Avatars Interaction always takes place in a context.

7.1 Ergonomics

 * Deals with the more physiological aspects of our natures. --> It recognizes that we have bodies which both facilitate and restrict the range and types of movement we can make.
 * Is interested in the reaction time, visual acuity, and reach.
 * Is used in design of aircraft cockpits, space suits, vacuum cleaners and mobile phones (Just a few examples).
 * Is a major selling point and is also important aspect of 'inclusive design' (from Ch. 3)
 * Has existed since World War 2 because technologically advanced weapons had to be adapted to the humans and environments using them.

Definition
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 * The scientific study of the relationship between humans and their environment (Murrell 1965). Note: Environment includes both ambient environment and working environment.
 * It draws on anatomy, physiological and experimental psychology, physics, engineering and work studies.
 * Examples of ergonomic design: ergonomic keyboard (Figure 7-1/pg. 165) that reflects the fact that we have two hands that are separated, as the keyboard is separated into two different sections of keys.

**Antropometrics**
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 * "The measure of man"--> used to ensure that ergonomic designs are usable in size for human (for the **average** man and woman)
 * Example of bad ergonomic design: small cell phones that most people are unable to use because of "fat" fingers (most human fingers are bigger than the keys on the cell phones).
 * Figures have been compiled from thousands of measurements of different races, ages and professions (eg. office workers vs. manual workers). These measurements and studies can be translated into formulas or laws which can predict the behaviours of humans.

Fitts' Law
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 * T (time to move) = k log2 (D/S + 0.5)
 * It's a mathematical formula which relates **the time** required to move to a target as a function of the **distance** to the target and the **size** of the target itself (eg. moving a pointer using a mouse to a particular button).
 * It describes motor control: the smaller the target and the greater the distance, the longer it will take to hit the target.

7.2 Avatars in CVEs
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 * CVE = collaborative virtual environment: A computer-based, distributed, virtual space or set of places. People can meet and interact with others or with virtual objects --> a space for both data and users (more in chap. 30)
 * Avatars embody humans in a CVE.
 * Group behaviour
 * a consequence of being embodied in a virtual environment.
 * Salem and Earle (2000) developed the concept of a social circle.
 * Communicate through visual cues such as a red light source to indicate a group is full.

7.3 Affordance

 * The original "affordance" concept is formed by James Gibson.
 * Affordance is a resource or support that the environment offers an animal; the animal in turn must possess the capabilities to perceive and use it.
 * Examples: surfaces that provide support, objects that can be manipulated, substances that can be eaten, and other animals that afford interactions of all kinds.
 * Properties of these affordances for animals are specified in stimulus information.
 * Once detected, an affordance is meaningful and has value for the animal. If ignored, it's dangerous.
 * Example from real world: opening a door. We can see that we can either push or pull it from the affordances of the door itself.
 * Donald Norman revised Gibson's theory of afforfance: wanted to replace the original biological-environmental formulation with a definition which is namely perceived affordance.
 * Intended and perceived behaviours are usually very simple: sliding, pressing and rotating.
 * THERE IS DIFFICULTY IN STATING EXACTLY WHAT AN AFFORDANCE IS.
 * Works best in anthropological examples.

7.4 Situated Action
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 * Is a paradigm suggested by Liam Bannon (paper published in 1991)
 * The paradigm suggests that potential users of collaborative systems are empowered. Problem-solving, value-laden, cooperative individuals and not just mere subjects in an applied psychology experiment --> move to real-world settings.
 * There is a difference in perception between treating people as merely a set of cognitive systems and subsystems.
 * Research must move from narrow experimental studies to the workplace.
 * Research should study experts and the obstacles they face in improving their competence or competence.
 * We should also move away from user-centred to user-involved design (aka participative design) which places the intended user at the centre of the design process.

From Lucy Suchman's //Plans and Situated Actions// (published 1987): > >
 * Critique of some core assumptions of Artificial Intelligence (AI) and cognitive science --> the role of plans in behaviour,.
 * Both humans and AI behaviour can be modelled in terms of the **formation** and **execution** of **scripts.**
 * A plan is a scripts, which are formulated through a set of procedures beginning with a goal and executed in order of these goals and sub-goals.
 * Suchman argues that nothing works out the way it is planned --> the world is unstable, dynamic and interpreted and the interpretation is contextual (or situated). Therefore, plans are not for execution, but just as one source which shape an individual's behaviour.

7.5 Distributed Cognition

 * Distributed cognition argues that cognitive processing is not confined to the individual mind, but distributed between mind and external artefacts.
 * It exists between the minds of cooperating human actors and artefacts.
 * It's best understood as a unified cognitive system with a particular goal.
 * Examples: using a calculator, a shopping list, navigating and driving in a foreign city.

Internal and external representation - internal = knowledge (human memory) - external = anything which supports the cognitive activity.

7.6 Activity Theory

 * Its origins in Soviet psychology (Marx, Leont'ev, Vygotsky). --> places emphasis on society and community, not the isolated community.
 * The theory asserts that human activity itself is the context.

- Cultural Historical Activity Theory, comprise a recognition of the role and importance of C, H and A to to understand human behaviours. - three basic principles from Engenstrom: - activities as the smallest meaningful unit of analysis - self-organizing activty systems driven by contradictions - changes in activities.
 * CHAT**

The structure of an activity - triadic interaction between a //subject// and the group's //object// mediated by //artefacts// or tools.