The human brain is limited in its capacity. The aim of this article is to explain why this is so in terms of attention and memory constraints. Furthermore, this article highlights the importance of designing for attention and, also, we will introduce some of the best techniques to structuring interfaces that are attention-grabbing and require minimal effort to learn and remember.
Our senses are constantly bombarded with images, sounds, smells, tastes and touch. The problem confronting us is how to deal with all this information in such a way as to make sense out of it. Most importantly, we need to avoid getting overloaded with information. So how do we achieve this?
Focused and divided attention
The ability of your brain to concentrate on one activity for a specified period of time has been psychologically termed as focused attention. The streams of information we choose to attend to will tend to be relevant to the activities and intentions that we have at that time. Instead, when we attempt to attend to more than one thing at a time, is called divided attention.
Focusing attention at the interface
One way in which interfaces can be designed to help users find the information they need is to structure the interface so that it is easy to navigate through. Firstly, this requires presenting not too much information and not too little on a screen, as in both cases the user will have to spend considerable time scanning through either a cluttered screen or numerous screens of information. Secondly, instead of arbitrarily presenting data on the screen it should be grouped and ordered into meaningful parts. By capitalizing on the perceptual laws of grouping, information can be meaningfully structured so that it is easier to perceive and able to guide attention readily to the appropriate information.
Other techniques for guiding attention
Additional methods for presenting information at the interface to guide attention include the use of:
Spatial and temporal cues,
Colors,
Alerting techniques such as flashing and reverse video and auditory warnings.
Windows are another useful way of partitioning the computer screen into discrete or overlapping sections, to enable different types of information to be separated. In using the various methods it should be noted that:
Important information that needs immediate attention should always be displayed in a prominent place to catch the user's eye (e.g. alarm and warning messages);
Less urgent information should be allocated to less prominent but specific areas of the screen so that the user will know where to look when this information is required (e.g. reports and reference material);
Information that is not needed very often (e.g. help facilities) should not be displayed but should be made available upon request.
Multitasking and interruptions
When carrying out tasks using computer systems in a work setting, people are continually interrupted by the moment to moment demands of the situation. This could be the phone ringing, the signaling of electronic mail arriving, and so on. In addition, it is common for people to do multitasking. While most people show great flexibility in coping with multitasking, they are also prone to distraction. On returning to a suspended activity, it is possible for them to have forgotten where they were in the activity. As a result, they may not restart from where they left off but will recommence at a different point of entry.
People have developed various strategies to remind themselves of the actions they need to perform at a later stage. The most common include writing lists, using post-it notes, and setting reminders on their phones. Norman (1992) describes these reminders as cognitive aids - prompts designed to help users complete a task or series of tasks.
Ideally, systems should be designed to provide information systematically about the status of an activity in terms of what has been done and what currently needs to be carried out. If users are distracted from the activity at hand, the system should be able to inform them of where they were in that activity when they return to it by displaying reminder prompts at the interface.
Memory constraints
Memory is involved in all our everyday activities (as are perception and attention). The human memory system is very versatile but is by no means infallible. It seems we find some things relatively easy to remember, while others are very difficult. The same is true when we try to remember how to interact with a computer system. Some operations are easy and take minimal effort to memorize while others take forever to learn - and often drop out of memory soon after they have been used.
What is the main factor that determines our ability to remember stimuli?
The more meaningful a stimulus is the more it will be processed and the more likely it is to be remembered.
Within psychological research, a number of factors have been found to contribute towards the meaningfulness of a stimulus. These include attributes such as the familiarity of an item and its associated imagery.
Meaningful interfaces
The fact that certain items are more meaningful than others has obvious implications for interface design. In particular, it suggests that items that need to be remembered at the interface should be as meaningful as possible, an example can be command names and icons. In contrast, the trend within computer science has been to select names that are highly abstract. A common technique is to use abbreviations or combinations of control keys. While these are quick to use, they have their drawbacks. A general guideline for the selection of command names is to consider the contextual, cultural, and user characteristics.
Another alternative is to design meaningful icons. As with command names, there are several factors that determine the meaningfulness of icons. These include the context in which the icon is being used; the task for which it is being used; the surface form of the representation; and the underlying concept that is being represented.
The use of icons is often favored as an alternative to command names. One of the main advantages is that, whereas it is quite common for users, especially those who see a system infrequently, to forget the meaning of command names, it is less so with icons. It seems that once users have learned the meaning of a set of icons they are much less likely to forget them than they would if they were just names.
Recognition vs recall
One of the most well-established findings in memory research is that we can recognize material far more easily than we can recall it from memory. The superiority that the phenomenon of recognition has over recall has apparent ramifications for interface design. Indeed the majority of user interfaces these days employ an extensive range of menus containing text or iconic lists of operations, options, files, and so on. Instead of having to recall a name or a particular combination of function keys to perform an operation the users only have to scan through the menu until they recognize the name or icon representing the object that is required.
In addition to using cognitive aids, people have developed various cognitive mnemonics to help them remember things. As we said above, a cognitive aid is an external representation that we use as a reminder to help us carry out a task that needs performing at a later time. A cognitive mnemonics is an internal representation that people develop to help them remember things, especially the ordering of the objects, such as the point of the compass.
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