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The aim of this report is to research into the subject of Human Computer Interaction (HCI) and more specifically the aspects which can result in its outcome being good or bad. Background information will be researched first in order to understand the topic area more thoroughly and then concepts and/or ideas that produce good or bad interaction will try to be identified. These factors, where possible, will be demonstrated using examples as they can show, more easily, how effective they can be or the problems that may arise with their inclusion.
After the research, recommendations will be made to highlight what the best ideas are that should be included in human computer interaction for it to be successful and the pitfalls that must be avoided so that the risk of issues arising can be minimised. Finally, there will be a conclusion that summarises the whole report.
The report will be split into the following sections:
Human Computer Interaction - This will involve initial research into the subject area and to try and understand what different areas make up HCI. It will also include the identification of good and bad HCI and their examples.
Recommendations - This will show the areas which must be thought about carefully in order to produce a good interaction experience.
Conclusion - This will be an overview of the main points that the report has identified and covered.
2. Human Computer Interaction
2.1 What is HCI?
Human Computer Interaction (HCI) involves focusing on how best to design interactive systems that are both productive and as pleasurable to use as possible by their intended users (Smith-Atakan, 2006). It can also be described as a discipline, which is concerned with the design, evaluation and implementation of interactive computer systems for human use (Ghaoui, 2006).
HCI covers each side of the interaction, human and machine, and tries to determine how they best work together in order to perform an end goal (e.g. use a computer system or product). It does this by taking knowledge from both sides and attempting to link it all together so that the interaction between user and system can be the best it possibly can be. The interaction usually involves feedback and control throughout the user performing a task. Feedback is considered to be a communication of immediate system state to the end-user (Renaud and Cooper, 2000). For example, the user invokes a "print" command and the interface responds with a dialog box alerting the user the request has been filled.
Therefore the main focus with HCI can be seen to be on the interface of the computer system that the user interacts with. Raskin (2000) states that an interface can be defined as the way we interact with a product, what we do, and how it responds. The design of the interface is important as this is the form of communication between a user and system. If an interface is badly designed then users may have issues trying to operate it and therefore the system as well. There have been a number of researchers that have tried to point out some concepts an interface's design should contain. According to Hollan et al. (2000), designing an interface deals with displaying as many clues as possible from which the user can infer correctly and quickly what to do next.
If designers can incorporate the best ideas and solutions for designing interaction between computer systems and humans then this should enable them to give users the best user experience (a person's emotions and perceptions towards using a particular system or product) as possible and an interface that they can easily understand and use.
2.2 Good HCI
HCI can be successful and that is because it incorporates a number of features that have been designed and implemented into the interaction between the interface and user. These features can relate to the user, the system and the combination of them together. A good design can be seen to include the following:
Affordance - makes each operation visible. E.g. buttons which indicate to the user they are to be pressed.
Figure : Button Affordancehttp://www.joelonsoftware.com/uibook/pictures/ETrade.gif
The above image (Spolsky, 2000) shows 3D buttons which appear to "pop-up" from the screen. This gives the affordance that they can be pushed so this means the user knows they need to be clicked on the operate them.
Mapping - makes the relationship between the action of the system/device and the action of the user obvious. E.g. the controls for a kitchen stove.
Figure : Bad Mapping Design
Figure : Improved Mapping Design
These images of the stove controls show the difference if you have incorrect mapping. In Figure 2 the user will not know which knob operates each hob but in Figure 3 the user can clearly see the association between the control and which hob it operates.
Feedback - provision of feedback on the user's action. E.g. the user clicks an icon to reverse an image and the image gets instantly reversed.
Figure : Rollover Feedback
The image above shows a good example of feedback for a website's navigation. When the user puts the mouse pointer over the link it is instantly highlighted to let the user know it is available for selection.
Mental Model - user understands the underlying behaviour of the device/system. E.g. if the user performs "Action A" on a system, then "Event A" will happen.
Forcing Functions - prevents the user from making bad errors. E.g. A user interface makes sure that specific buttons cannot be selected when the user is performing a certain action.
Figure : Forcing Function - Delete File
Figure 5 (Norman, 1988) shows an example of a forcing function that is executed when a user wants to delete a file. It "forces" the user to commit to the deletion by verifying the action they originally wanted to perform.
These features show that they, when correctly implemented, provide users with interaction that should be easy to understand allowing processes such as navigating a web site to be completed with the least amount of difficulty as possible. This results in the user gaining confidence with the interface, how it operates and therefore, as a whole, the product and/or system.
2.3 Bad HCI
As well as the good HCI that exists there is the opposing bad HCI. These are generally issues with bad user interface designs resulting in users finding them hard to understand and use and therefore producing errors that could cause disaster. The following shows some examples of bad HCI:
Three Mile Island Accident - This was a power plant that has a partial nuclear meltdown. This was caused by the power plant's user interface having ambiguous control room indicators which when combined with poor training of the users and one of the indicators being hidden resulted in a process being committed which shouldn't have. It was supposed to fix an existing problem but because incorrect procedures were followed it only made the problem worse producing a disastrous result.
This could have been avoided by having an interface design which didn't contain ambiguity and showed all of the controls on one panel so that none of them could be hidden.
Error Messages - An incorrect error message displayed to the user can result in them not knowing how to fix the issue they encountered so will not be able to continue with their work.
Figure : Error Message
The error message shown (Popyack, 2010) does not give the user any indication of what kind of error occurred and what they could do to fix it.
Colour - The incorrect use of colour can have a negative impact on an interface. Users can possibly have some form of colour blindness so has to be though about when choosing a colour scheme.
Figure : Bad Use of Colour
The above image shows an interface that doesn't use colour in the best way possible and could result in users struggling to read the words which could result in errors if the words were a set of instructions.
Interfaces can easily be designed that incorporate features that result in bad interaction between the users and the system. Designers have to try to avoid or minimise these so that users do not have a bad user experience which may result in them not using the system altogether.
3.1 Shneiderman's Golden Rules of Interface Design
Ben Shneiderman is a researcher who has contributed a lot in the field of human computer interaction. He proposed 8 "golden rules" for interface design (Shneiderman, 2009) that are recommended to designers in order for them to develop interactive systems which offer good usability. They are as follows:
Strive for consistency - Consistent sequences of actions should be required in similar situations. Identical terminology should be used in prompts, menus, and help screens. Consistent colour, layout, fonts should be employed throughout.
Enable frequent users to use shortcuts - As the frequency of use increases, so do the user's desires to reduce the number of interactions and to increase the pace of interaction. Abbreviations, function keys, hidden commands, and macro facilities are very helpful to an expert user.
Offer informative feedback - Offering informative feedback to the users for the actions they do gives the users confidence that they are proceeding in the right direction.
Design dialog to yield closure - Sequences of actions should be organised into groups with a beginning, middle and end.
Offer simple error handling - As much as possible, design the system so the user cannot make a serious error. If an error is made, the system should be able to detect the error and offer simple mechanisms for handling the error.
Permit easy reversal of actions - This feature relieves anxiety, since the user knows that errors can be undone and therefore also encourages exploration of unfamiliar options.
Support internal locus of control - Experienced operators strongly desire the sense that they are in charge of the system and that the system responds to their actions. Systems should be designed to make users the initiators of actions rather than the responders.
Reduce short-term memory load - Human processing is limited in short term memory. Therefore displays should consolidate multiple-page displays and reduce windows-motion frequency so they can be kept simple.
If the above rules can be followed when designing and implementing the interaction of a system then it should ensure that the usability is maximised meaning users can easily use the system therefore giving them a good user experience.
Human Computer Interaction is an important subject. This is because new computer systems are being developed all the time and users are needed to operate them, in order to fulfil operations and processes for personal or business purposes. Due to the problems that can arise during the interaction between humans and computer systems the interaction has to be carefully designed and implemented for each individual system so that users can use them without difficulty. If this is done successfully then usability should be the best it can be resulting in good HCI and ultimately users finding interaction with systems straightforward to understand and easy to use.