P2 - The fundamental principles of HCI design

P2 - The Fundamental Principles of HCI Design

HCI (Human Computer Interaction) is the study, planning, and design of the interaction between people and computers. The human side of this is how the computer and the user interact, graphic and industrial design disciplines, human language, and human factors such as the satisfaction the user gets when using the computer. On the other hand, the computer side is computer graphics, operating systems and programming languages.

Perception is an essential feature in HCI design. It is the structure, recognition and understanding of sensory information in order to characterise and recognise your surrounding. When you look at an image that is an illusion your mind fills in the blanks making you see the full picture. The colours of the image or the interface affect each user differently making it something to keep in mind when designing one. Medical conditions such as; dyslexia and colour blindness effect the way the user views the page. Colour is caused by the way your brain views it. The appearance of colours is affected by others that are nearby. Information can be affected by the colours used, such as some look darker and smaller against a white background, whereas, some look brighter and larger against a white background.

    

Another fundamental principle of HCI design is behaviour models. They predict the way in which an interface or user will behave. There are two types of models; predictive and descriptive. Predictive models are used to compare and assess motor behaviour when designing interfaces and systems whereas descriptive models help to understand interaction situations. Examples of this is Guiard's model. This is a model of how human's use their hands and it identifies the roles and actions of the preferred and non-preferred hands that we use. Such as, being left or right handed. A right handed person would be able to use an ordinary keyboard with ease, whereas, a left handed person may find it more difficult.

Information processing is also a fundamental principle of HCI design. It has many features that have to be considered. For example, the human as a component. This has to be thought about because the interface is designed for the human to use. Also, the human information process is a feature to be considered. It is when the human is thought to be like the computer; the senses are the input devices, the brain and mind are the CPU and the action that you perform is the output device. A final feature that has to be considered is an overview of goals, operators, methods and selection. It helps to predict the time it will take for the actions to be carried out. The goal is a description of what the user wants to achieve, the operator is possible actions in the system, the method is a sequence of operators that achieve the goal and the selection is rules that define when a user employs which method.

Specialist interfaces are a fundamental principle of human computer interaction. They can be voice recognition software, speech synthesis, language translators and eyegaze. They are used in everyday life to make it easier for disabled people to use computers and other technology. Other types of specialised interfaces include; remote control devices and head up displays. Remote control devices are used most commonly in the home for TV remotes using infrared. Head up displays are used so that the user doesn't have to look away from their main viewpoint. It is used, for example, in aircrafts to make it safer for the pilot and passengers as the driver doesn't have to look away from the air in front of them.

Another fundamental principle of HCI design is geons and gross 3D shapes. They are needed in the creation of interfaces. Geons are 2D shapes that are quickly recognisable from any angle. Such as, cylinders, bricks, wedges, cones, circles and rectangles. There are four essential properties of geons;

• View-invariance
• Stability or resistance to visual noise
• Invariance to illumination direction and surface markings and texture
• High distinctiveness

Gross 3D shapes are 2D shapes that give the impression of three dimensional shapes. This is done by placing the image lower or higher on the page. They are used to make reproducing images more consistent and they are relatively cheap to produce. Most commonly they are used in video games and in real time transmission, such as at football games.