Human Computer Interaction

Introduction

What is Human Computer Interaction?
Is the study of the relationships which exist between human users and the computer systems they use in the performance of their various tasks.

HCI seeks to provide an understanding of how users function, the tasks they need to perform and the way in which a computer systems needs to be structured to facilitate the easy carrying out of those tasks.

The importance of HCI

• HCI is important in the design process since the computer interface is the first point of contact the user has with the system and the user will judge the system on the basis of the interface.
• Systems should consider some aspects of the cost:
• The cost of software is high and the competitive edge is more difficult to achieve. The interface to a system might give it this edge.
• The cost to train users is high, therefore, a system which is easy and natural to use will save money in the long run, since the training time will be kept to a minimum.
• The cost of human error can be high. Systems that are transparent ought to reduce the likelihood of error or to aid error recovery.

Taxonomy of HCI

• Use and context
o social organization and work
§ Points of view (e.g. Industrial engineering, operations resesarch)
§ Models of human activity
§ Models of small groups and organisations
§ Models of work, workflow, offices.
o application areas
§ Characterization of application areas (eg. Individual, group)
§ Document-oriented interfaces (eg. Text-editing, document formatting, spreadsheets, hypertext)
o human-machine fit & adaptation
§ Arrange a fit between the designed object and its use.
§ Changes to fit can be made
· At a design time/ at time of use
· Either changing the system or the user
• Human characteristics (how people work and how they are expected to interact with machines)
o human information processing
§ Phenomena and theory of memory, perception, motor skills, problem solving, motivation.
o language, communication, and interaction
§ Syntax, semantics
§ Graphical interaction, query, command
o ergonomics
§ physical factors
§ mental factors
• Computer system & interface architecture
o input & output devices
o dialogue techniques
o dialogue genre
o computer graphics
o dialog architecture
• Development process
o design approaches
o implementation techniques & tool
o evaluation techniques

Components of HCI
1. Human -user
2. Computer - mediator
3. Interface - used

Relationship of HCI to other disciplines
HCI

Engineering

Artificial Intelligence

psychology

Computer Science

physiology

Anthropology

Ergonomics

Linguistics

Philosophy

Art

Sociology

Disciplines contributing to HCI
• Computer Science
o To provide knowledge about the capability of technology and ideas about how this potential can be harnessed.
o Concerned about developing various kinds of techniques to support software design, development and maintenance.
• Cognitive Psychology
o Concerned with understanding human behavior and the mental processes that underlie it.
o To account for human behavior, cognitive psychology has adopted the notion of information processing such as what we see, what we touch, what we taste.
• Social and organizational psychology
o Concerned with studying the nature and causes of human behaviour in a social context.
o The role of social and organizational psychology is to inform designers about social and organizational structures and about how the introduction of computers will influence working practices.
• Ergonomics
o Developed from the interests of a number of different disciplines.
o Its purpose is to define and design tools and various artifacts for different work, leisure and domestic environments to suit the capabilities and capacities of users.
• Linguistics
o Is the scientific study of language
o Understanding of the syntax (structure) and semantic (meaning) is important
• Artificial Intelligence
o Concerned with the design of intelligent computer programs which simulate different aspects of intelligent human behaviour.
o The relationship of AI and HCI is mainly concerned with users’ needs when interacting with an intelligent interface.
• Philosophy, sociology and anthropology
o Traditionally, they have not been directly involved with the actual design of computer systems, but rather with the consequences of developments in information technology and technology transfer.
• Engineering and design
o Engineering is the applies science which relies heavily on model building and empirical testing. its takes the findings of science and utilizes them in the production of artifacts.
o Design contributes creative skills and knowledge to this process.

Factors in HCI

Human Factors (Ergonomics)

• Is the study of the physical characteristics of the interaction:
• How the controls are designed
• The physical environment in which the interaction takes place
• The layout and physical qualities of the screen.

Issues Addressed by Ergonomics

• Arrangement of controls and displays
• Sets of controls and parts of the display should be grouped logically to allow rapid access by the user.
• Should be organized in terms of:
• Functionality – controls and displays are organized so that those that are functionally related are placed together
• Sequential - controls and displays are organized in a particular task sequence.
• Frequency - controls and displays are organized based on the frequency of used
• The physical environment of the interaction
• Where will the system be used
• By whom will it be used
• Will users be sitting, standing or moving about
• Considerations
• Size The smallest user should be able to reach all the controls (this may include a user in a wheelchair), and the largest user should not be cramped in the environment. In particular, all users should be comfortably able to see critical displays.
• Seat For long period of use, the user should be seated for comfort and stability, and seating should provide back support.
• Stand If required to stand, the user should have room to move around in order to reach all the controls.
• Health Issues
• These are the factors in the physical environment that directly affect the quality of the interaction and the user's performance :
• Physical Position
• Temperature
• Lighting
• Noise
• Time
• The use of colour
• Importance of Arrangement of Control and Displays
• Give strong emotional reaction
• Add accents to an uninteresting display
• Facilitate subtle discrimination in complex displays
• Emphasize the logical organization of information
• Draw attention to alert the users