INF1520 - Human-computer Interaction

INF1520 - Human-computer Interaction

1. Learning Unit 1: Introduction to Human-Computer Interaction

   • The historical context of human-computer interaction
     • < 1450
       • Persian astrologer, __Al-Kashi__, used a device to calculate the conjunction of planets.
     • 1600
       • The German mathematician, __Wilhelm Schickard__, developed a tool to perform simple addition and subtraction.
       • Blaise Pascal built a simplified replica of __Schickard__’s device.
     • 1820 - 1870
       • Charles Babbage built his __Difference Engine__ to calculate 6th degree polynomials.
       • __Charles Babbage__ developed his Analytical Engine, which was the first calculating device to use punched cards.
     • __1887__
       • Herman Hollerith developed a computational device, using punched cards, to calculate census statistics.
     • 1914
       • Thomas J Watson joined the __Computer-Tabulating-Recording Company (1911)__ Company and built it up to form the International Business Machines Corporation (IBM).
     • 1943
       • __Alan Turing__ developed the __Colossus__ to try and break German encryption techniques. The Colossus accepted input via a keyboard and produced output via a teleprinter.
     • __1945__
       • Vannevar Bush published his ‘As we may think’ article in Atlantic Monthly, introducing his Memex system.
     • 1946
       • The __ENIAC__ machine, the first all electronic digital computer, was produced by J W Mauchly and J P Eckert in the United States.
     • __1957__
       • IBM introduced the FORTRAN high-level programming language.
     • 1963
       • Ivan Sutherland developed the __SketchPad__ system at the MIT Lincoln Laboratory, the first sophisticated drawing package.
     • 1976
       • Steven Wozniak produced Apple I, based on the __MOStek 6502__ Chip.
     • __1981__
       • IBM produced their first PC with DOS.
     • 1982
       • Xerox produced their __STAR__, in which files were represented by icons and were deleted by dragging them over a wastebasket. This marked the advent of the modern desktop.
   • Ubiquitous computing (UbiComp):
     • This refers to computer systems that are embedded in everyday objects and thus, unobtrusively, become part of the environment. An example is a computerised control system found in a modern car (for example, activating the windshield wipers at the appropriate wiping speed when it detects rain).
   • Definitions of HCI
     • HCI is a ‘set of processes, dialogues, and actions through which a human user employs and interacts with a computer’ (Baecker and Buxton, 1987).
     • HCI is a ‘discipline concerned with the design, evaluation, and implementation of interactive computing systems for human use and with the study of major phenomena surrounding them. From a Computer Science perspective, the focus is on interaction and specifically on interaction between one or more humans and one or more computational machines’ (ACM SIGCHI, n.d.). A computational machine (computer) is defined to include traditional workstations as well as embedded computational devices, such as spacecraft cockpits or microwave ovens, or specialized boxes such as electronic games. A human is defined to include a range from children to the elderly, computer aficionados to computer despisers, frequent users to hesitant users, big hulking teenagers to people with special needs, etc.
     • HCI is ‘the study of people, computer technology, and the ways these influence each other’ (Dix et al., 2004). A (human) user is defined as whoever is trying to accomplish something using the technology and can mean an individual user, a group of users working together, or a sequence of users in an organization, each dealing with some part of the task or process. The computer is defined as any technology ranging from the general desktop computer to large-scale computer systems, a process control system, or an embedded system. The system may include non-computerized parts, including other people. Interaction is defined as any communication between a user and the computer, be it direct or indirect. Direct interaction involves a dialogue with feedback and control during performance of the task. Indirect interaction may involve background or batch processing.
     • HCI is concerned with studying and improving the many factors that influence the effectiveness and efficiency of computer use. It combines techniques from psychology, sociology, physiology, engineering, computer science, and linguistics (Johnson, 1997).
   • Ergonomics
     • Ergonomics is the study of work. The term is most widely used in the United Kingdom and Europe, in contrast to the United States and the Pacific basin where the term ‘Human Factors’ is more popular (see below). Ergonomics has traditionally involved the design of the ‘total working environment’; this includes the height of the chair, table, etc. Health and safety legislation, such as the UK Display Screen Equipment Regulations (1992), is increasinglyblurring the distinction between HCI and ergonomics. In order to design effective user interfaces, we must consider wider working practices. For instance, the design of a telesales system must consider the interaction between the computer application, the telephone equipment and any additional paper documentation.
   • Human Factor
     • A human factor is a term used to describe the study of user interfaces in their working context. It addresses the ‘entire person’ and includes:
       • Physiology, our physical characteristics such as height and reach.
       • Perception, our ability to sense information, hearing, touch, and sight.
       • Cognition, the way we process data, such as the information we extract from a display.
   • Usability
     • Usability is defined by the International Standards Organization (ISO) as “the extent to which a product can be used by specified users to achieve specified goals with effectiveness, efficiency and satisfaction in a specified context of use”. The ISO standard 9241 gives the following definition of the components:
       • Effectiveness: The accuracy and completeness with which specified users can achieve specified goals in particular environments.
       • Efficiency: The resources expended in relation to the accuracy and completeness of goals achieved.
       • Satisfaction: The comfort and acceptability of the work system to its users and other people affected by its use.
   • Interaction design
     • Interaction design is defined by Preece et al. (2007, p. xvii) as “designing interactive products to support the way people communicate and interact in their everyday and working lives”. It involves four activities, namely:
       • Identifying needs and establishing user requirements.
       • Developing alternative designs according to the requirements.
       • Building prototypes of the designs so that they can be assessed.
       • Evaluating the designs and the user experience.
   • User Experience
     • User experience refers to how people feel about a product. How satisfied are they when using it, looking at it, or handling it? It includes the overall impression as well as the small effects such as how good it feels to touch. According to Preece et al. (2007) you cannot design a user experience, you can only design for user experience.
   • Accessibility
     • Accessibility in the context of HCI is ‘designing products so that people with disabilities can use them. Accessibility makes user interfaces perceivable, operable, and understandable by people with a wide range of abilities, and people in a wide range of circumstances, environments, and conditions. Thus accessibility also benefits people without disabilities, and organizations that develop accessible products’ (Henry, 2007). It is the degree to which a system is usable by people with disabilities (Preece at al., 2007). Some people see accessibility as a subset of usability, while others regard it is a prerequisite for usability.
   • Learning Unit 2: Human Issues in HCI
     • Cognitive Psychology in HCI
       • Perception:
         • the way that they detect information in their environment.
           • Colour
             • Colour hue
               • describes the perceptual attributes associated with elementary colour names. Hue enables us to identify basic colours, such as blue, green, yellow, red and purple. People with normal colour vision report that hues follow a natural sequence based on their similarity to one another.
             • Colour lightness
               • corresponds to how much light appears to be reflected from a surface in relation to nearby surfaces. Lightness, like hue, is a perceptual attribute that cannot be computed from physical measurements alone. It is the most important attribute in making contrast more effective.
             • Colour saturation
               • indicates a colour’s perceptual difference from a white, black or grey of equal lightness. Slate blue is an example of a desaturated colour because it is similar to grey.
       • Cognition:
         • the way that they process that information.
           • Short-term memory and information processing
             • STM has a relatively short retention period and is limited in the amount of information that it can keep. It is easy to retrieve information from STM. Some people refer to STM as ‘working memory’, since it acts as a temporary memory that is necessary to perform our everyday activities. Effectiveness of STM is influenced by attention – any distraction can cause information to vanish from STM. Generally, people can keep up to seven items (e.g. a seven digit telephone number) in STM unless there is some distraction.
           • Long-term memory and learning
             • LTM, in contrast, has high capacity. As its name suggests, it can store information over much longer periods of time, but access is much slower. It also takes time to record memories there. If we have to extract the information from LTM it may involve several moments’ thought: for example, naming the seven dwarfs or the current members of the national soccer team. The information stored in LTM is affected by people’s interpretation of the associated events or context. Information retrieved from LTM is also influenced by the retriever’s current context or state of mind.
           • Retrievability
             • Knowledge in the world
               • Easily retrievable whenever visible or audible. (Depends on availability in the environment.)
             • Knowledge in the head
               • More difficult to retrieve. Requires memory search or reminding.
           • Learning
             • Knowledge in the world
               • Learning is not required, only interpretation.
             • Knowledge in the head
               • To get information there requires learning, which can be considerable.
           • Efficiency of use
             • Knowledge in the world
               • Tends to be slowed up by the need to find and interpret the external sources.
             • Knowledge in the head
               • Can be very efficient.
           • Ease of use at first encounter
             • Knowledge in the world
               • High
             • Knowledge in the head
               • Low
           • Aesthetics
             • Knowledge in the world
               • Can be unaesthetic and inelegant, especially if there is a need to maintain a lot of information. Can lead to clutter. Requires a skilled designer.
             • Knowledge in the head
               • Nothing needs to be visible, which gives the designer more freedom.
       • Physiology:
         • the way in which they move and interact with physical objects in their environment.