P2 - Fundamental Principles of HCI

Task: P2 - explain the fundamental principles of HCI design.

Perception:

The perception of something can be seen differently depending on how the user looks at it. So when it comes to designing the GUI, you will need to design it in such a way, that anyone who comes across it, can use if perfectly without confusion. When creating the GIU, there may be more than one person involved with the idea, so making sure that everyone has the same understanding of what it will look like, is important, otherwise the client of whoever is paying, may not be happy if it’s completely different to what he had in mind from the start.

Not only that, but they also need to take into account their target audience, and if it’s able to be used by disabled users, etc.

·         Colour: when choosing colours, it’s important to ensure that the target audience has been taken into account, so that it looks attractive and draws the audience in, they need to make sure that the colours aren’t sexist or discriminate against certain types of people. Things like this all need to be taken into account. Also, disabled users, for example, the colour-blind, need to be able to use it. It’s no good creating a nice GUI, but the visually impaired cannot use it because, things like colours, have not been picked correctly for them, etc.

·         Luminance: This is a system of colours that is used to make sure that the end-user has the best possible visual effects. The most common type of system used is one called Trichromatic system, which uses three colour types to display its colours, which are; RED, Green, and Blue (RGB). RGB is the best way to display colours due to the way our eyes work, and how our eyes see these colours on screen. The best thing for this is to have a certain colour text on a certain background to make sure that the text is easy to read under different conditions. The designers need to take into account, the brightness of user’s screens for example.

·         Pop out effect: This is an effect that is used to make our eyes focus on a specific item or object. They do this by using brighter colours against dull ones, etc. This technique is used to make sure that the user focuses on a certain element on whatever they are doing, for example, a website designer is going to want to make sure that his buttons and navigation bar stands out on his website, so he will make the text bigger, used different colours, etc., to make sure that the user sees this easily, otherwise they user will have to spend time looking for the buttons.

·         Pattern: the pattern is essentially the template used when creating an interface. Using this allows the user to easily navigate the interface with minor problems. An example of this could be the apple website. All the buttons are always in the same place, easy to read and find, allow the users to navigate easily. Pattern is made up of six sections which are: Proximity, Continuity, Symmetry, Similarity, Common Groupings, and Connectedness.

·         Objects: Objects are essentially the parts that make up the interface, for example, the buttons, the menus, etc. Being a designer you will need to take into account the sizes and shapes of the objects, so that it fits in will the background and/or is suitable for the end-user.

·         Geons and Gross 3D shapes:  Geons are simple 2D shapes such as, cones, circles, rectangles, bricks, etc. that can be easily viewed and given a perspective of 3D. These shapes are quickly recognisable and are normally broken up and arranged, giving the illusion of a 3D object to the human eye. Gross 3D: these are 2D shapes that also give the illusion of being 3D shapes to the human eye. To give the illusion, the shape in normally copied and moves slightly higher/lower and to the left/right of the original shape.

Behaviour Models:

Previous successful models or templates are generally sued to create a new device or interface as the creators knows that it works, they then just alter it slightly or make it better in some ways. The reason that they do this is because, it decreases the time needed to think of new designs and decreases resources used as well. Not only that but creating a completely different user interface can make it harder for users to navigate around if they are used to the previous one.

·         Predictive: Predictive modelling is the process where you try to predict the outcome of something, for example, if you are creating a new game, from what is in the game, the colour scheme, if there is any violence, etc., you can predict the target audience and if it will sell well or not. In relevance to HCI and GUI, the more complex the interface, the smaller the market will be for your product.

·         Keystroke-level: The keystroke-level model is used to estimate the time it takes to complete a simple input task using a computer and mouse. By using this method, people normally find more efficient ways to complete a specific task, by looking at what steps are involved in the task, and getting rid of any unnecessary steps or rearranging the steps to make it more efficient.

·         Throughput: This is used to estimate how long it will take to transfer a specific amount of data from location to another and/or the amount of work the computer can do/handle in a given time period. An example of this would be how long it takes to transfer data from your computer to a USB memory stick.

·         Fitts’ law: Fitts’ law is an equation that is used to calculate the time it takes for you to reach a target object. For example, the time it takes for you to move your mouse to click on a button or link on a website. The equation looks like this: T=a+b log2 (2 d/w)

·         ‘T’ stands for time. The amount of time it takes for you to get to your targeted object.

·         ‘a + b’ stands for the two coefficients. ‘a’ is the start/stop time of the device. ‘b’ is the speed of the device.

·         d stands for distance to the targeted object.

·         w stands for the width to the targeted object (on an axis).

Buxtons 3 state model: This is where the user makes a moving using the mouse, touch pad, or the mouse wheel. The first state is the human contact with the mouse. The second state is moving the tracking symbol (the cursor). The third state is moving something on the desktop, for example an icon.

Guiard’s Model: this is basically, when creating HCI models, you create them in such a way, that both left-handed and right-handed people can use the effectively. For example, a keyboard or a mouse, you have the option to change what buttons do what.

Information Processing: This section is more about what the humans do to deal with the information we are given and what we do with it after. This is where we get both the human way of processing information and the way the computer does it, and we use this to build a better computer interaction. This allows us to build a more efficient way of communicating with each other. Without this, it would be incredible hard to use new products because you would have to learn a new interface every time you buy a new product.

·         Humans as a component - This is basically saying that by treating humans as a component, we can make interfaces that are designed around us and are perfect for humans as a whole. This means that the end-user will have everything that it needs. When creating a HCI, it is important to think about who will be using it (the target audience). This way, the designer can create it around that. The designer will have to think about what the requirements of the end-users are (so research about it).

·         Human Information Processing (HIP) – Making sure that the interface is easy to understand and optimal for the end-user all comes under HIP. This principle is used to analyse how we, the humans, process certain types of information, and how we then input it into a HCI machine of some type. Many people believe that humans and computers both have similar way of storing data, long-term and short-term.

Computers on the other hand, are able to perform calculations much fast than we can, and also go on for much longer without slacking, so in some respect computers are more efficient, but, don’t forget that it’s humans that input the data in the first place, as computers cannot think for themselves.

·         GOMS (Goals, Operators, Methods, Section Rules):

Goals – These are what people are aiming towards by the end. When working on a task, you will have short-term goals and long-term goals that you and/or your team will be working towards.

Operators – these are the actions that need to be taken in order for the intended task to get done. For example, in order to go onto another webpage, you will need your mouse to click, and your keyboard to type in the webpage you want.

Methods – this is the plan that is going to be used in order to get something done. For example, if you wanted to move a shortcut to the recycling bin, you will first have to think about moving your mouse to pick up shortcut, you will then need to move into the recycling bin.

Selection rules – This is the method you will use in order to complete a specific task. First of all you will need to identify what the task is you are going to do, then you must think about what the most efficient method is to complete the task.