Perception

What is perception in HCI?


Perception is what the user see's and feels when they are using a HCI. To help us see, feel and use a HCI designers use colors, patterns and objects. 


Colour can determine if the user should be careful or not, or if the user need to take action within the HCI, or it can also tell the user that there is nothing to worry about. Designers use color to help users use HCI's. It is natural for us as humans to think that red means dangerous, yellow means be careful and green means that everything is fine, and designers use this to their advantage and to help us make HCI's more easy to use. 


For example, I use an Anti-virus called Avast Free Anti-virus. When the anti-virus detects no viruses and also detects that it is up to date it will display "secured" in green writing, because the writing is green and also reads "secured" it makes me feel more secure and safe. When a virus is detected and action needs to be taken it will display "not protected" in red writing. The red writing indicates within itself that action needs to be taken, the red writing also makes me feel unsafe. 


As well as drawing attention to users and notifying users, color is also used in HCI's to improve navigation. By using colors consistently it can help users to navigate to find the right information. 


An example of how color is used in Windows 7 is in the my computer window. When a hard drive has plenty of space the image will show blue. When the hard drive becomes full the bar will become red indicating that there is a problem. 


Patterns are also used in HCI to widen the users experiences of using the HCI. Designers use many different patterns and ideas to make HCI's easier to use.


 Designers use proximity to make items and windows appear closer then others. An example of this is if you have 2 windows open in an operating system you are actively using 1 window, this window will appear closer then the other window. 


Designers also use continuity to indicate to users that something is working or thinking, an example of this is when you are uploading a photo to Picassa via an android phone, a bar will appear with a pattern inside moving left to right indicating that the computer is continuously working at the moment.

 Designers also use similarity a lot, for example on an IPhone, if 2 apps are similar and work together or the user needs to use both applications to produce a product or result then the icons for the applications will look very similar. 

HCI designers also use objects to help users to interact with HCI's. They quite often use 3D shapes to help users to interact with HCI's. Instead of using 2D shapes which can be seen as boring they use 3D versions of the shapes, these could be arrows or just normal shapes, but 3D makes objects look more interesting meaning the user would be more happy using the HCI because it's more interesting. 2D objects are also widely used in HCI's because of how easily recognizable they are. Many different objects are used in HCI's such as squares, circles and arrows. The human brain can process 2D shapes very quickly meaning that users can interact with very quickly when the shapes are in the form of interactive material or hyperlinks.

Information processing

In HCI there 3 main principles of information processing, human as a component, human information processing, and goals operators methods and selection rules.

Human as a component

The principle of human as a component is where people believe that part of a computer/HCI is the human, its the theory that humans are a component of a computer or HCI, because the human is apparently a main component of a HCI, HCI's have to be designed to meet the main components needs (the human). The most important thing to think about when creating an HCI is the humans who are going to be use it. The people designing an HCI have to think what the user wants from the HCI, and how do they want to interact with it. They also have to think about how they HCI is going to be used and what the user needs and required the HCI to do. The designers will also have to research to find out what the humans requirements are. Designers will also have to figure out how they have met the requirements, I would do this by getting humans to test the HCi.

Human information processing 

Human information processing is the principle which is a theory that humans work like computers do. People believe that the senses (hands, eyes, mouth & nose) are the input devices (this could be referred to as like a mouse or keyboard). The brain and mind are the central processing unit which thinks and calculates and produces something to output. The output devices are an action you perform using your body or an action you perform on a computer.

When humans are referred to as computers, they are both referred to as either more intelligent or less intelligent then computers.It is very hard to tell if humans are actually smarter then computer or not. Computers can deffinatly be seen as less lazy then humans. Computers only sleep when you tell them to, meaning that they can work 24/7. Computers do not get bored, they can perform basic and advanced calculations and deal with situations easily. Multi-core computers can perform more than one advanced calculation in a second then older computers, meaning that new computers are very efficient, especially with the release of Quad core and Hex core.  Humans on the other hand cannot perform as many tasks in a second as computers can. Humans also have better hearing, good image processing and we are very good at detecting anomalies. The main thing that computers don't have that humans do is common sense.

Overall I think that the question:  "Are humans smarter than computers?" is unanswered.

GOM's

GOM's stands for goals operators methods and selection. It is a specialist model that allows researchers and users to see what tasks are undertaken on a HCI and how the tasks are undertaken on an HCI.

Goals is what the user wants to do, what task do they want to complete? An example of a goal is saving on Microsoft office Word.

Operators is the physical movements and actions that need to be taken. An example of this is a click of a mouse.

Methods are the other methods the user can take to accomplish the task or goal they need to complete within the HCI. The best way to accomplish at task or goal is to use shortcut keys. 


Selections is the easiest and quickest way of accomplishing a task or goal within a HCI.The quickest way to reach a goal in a HCI is to use the shortcut key if there is one available. For example if you want to print in Microsoft Word, you can use the mouse to click on print, but the quickest way  is to use the shortcut key (CTRL+P). This is quicker then because it takes less time to do a short key command then using the mouse to navigate to the print button.

GOM's is quite unreliable because it does not predict users behaviour being affected by fatigue, social surroundings, or organizational factors.

When Designers use GOM's they have to account for errors, they can only do this by predicting where the errors are to occur, and predict the time it takes to correct the error.  

Predictive Models

There are 6 behaviour models that help HCI designers to predict the way an interface will behave, and if it is effective enough to be used on a computer or device. These 6 behaviour models are split into 2 catorgories, predictive and descriptive.

The predictive models are:

•  Keystroad-level model (KLM)
• Throughput (TP)
• Fitt's law

The discriptive models are:

• Key-action model 
• buxton's three state model 
• Guiard's model of bimanual skill 

I am going to look at 1 predictive model and one descriptive model. 

keystroke level model  (predictive model)


The keystroke level model was described by Card, Moran, and Newell in the early 1980s. The model focuses on how long it takes users to actually use the HCI via hardware. The keystroke level model features 11 steps that is used by individual people and organisations, they use this to estimate how long it takes to perform simple tasks involving the input of a human via hardware. Normally companies who cannot afford specialists use this method. 


The keystroke level model defines and measures how long it takes to press and release a key on the keyboard (measured in words per minute, and categorised into fast, novice and slow typists), how long it takes to point the mouse on the screen, how long it takes to press or release a mouse click, how long it takes to switch hardware devices, ie keyboard and mouse, how long it takes for the human brain to prepare to peform an action within an HCI, how long it takes to type a string of characters,how long the user has to wait for the system to perform the action in the HCI. 

The key-action model (KAM) (discriptive)

Computer keyboards today contain a vast array of buttons, the buttons are either symbol keys, executive keys, or modifier keys. Symbol keys deliver graphic symbols — typically, letters, numbers, or punctuation symbols — to an application such as a text editor. Executive keys invoke actions in the application or at the system-level or meta-level. Examples include ENTER, F1, or ESC. Modifier keys do not generate symbols or invoke actions, but, rather, set up a condition necessary to modify the effect of a subsequently pressed key. Examples include SHIFT or ALT. Basicly, this model looks at how users interact with HCI's using keyboards and what shortcut keys HCI's use.