Although human brains still are vastly more powerful and intelligent than computers, computers are much better than people when it comes to remembering things. Much of the work done in human-computer interaction is focused purely on ways to reduce the load on the human user's memory. By understanding how humans remember things, we can develop effective strategies for aiding our memory - and can improve training programs.

How Human Memory Works

Educational psychologists still do not know for certain how people process and remember things. The "information processing model" is the best explanation to date. It is the model for both instructional systems theory and user interface design. The diagram below shows step by step how humans process information from a computer. First, the computer provides external stimuli in the form of text, pictures, and audio that gains the attention of the receptors in the eyes and ears. The receptors pass this information into sensory storage for automatic processing. Sensory storage processes all stimuli in real-time, so as new information comes in, it replaces the previous information.

Stimuli --> Receptors (Eyes, Ears, Hands) --> Sensory Storage --> Short Term Memory --> Long-Term Memory

Stimuli, or information, that has any value to the perceiver will be passed along into short-term memory, also known as working memory. Scientists have shown that short-term memory can only hold about seven to nine items at a time, and these items will be held for only about 30 seconds unless a memory aid is used, such as repetition or chunking.

For an everyday example of the use of a short-term memory aid, consider how you try to remember a phone number given to you when you don't have pen and paper handy. You might repeat the number several times to keep it present in your short-term memory - "908-555-1212, 908-555-1212, 908-555-1212". Of course, rather than memorizing one long string, "9085551212," you would "chunk" the numbers into three smaller pieces - "908-555-1212" -- to aid your memory.

The ultimate goal of training and education is to get relevant information through short-term memory and into long-term memory where it can be accessed at a later time. Long-term memory is like a giant warehouse where you keep many of your previous experiences and knowledge - memories of your high school prom, details of a play you saw, or important information about business competitors.

The real challenge when working with long-term memory is not just how to store information in that memory area, but rather how to get it back out again when needed. Research indicates that there are many tactics that will improve a person's ability to find and access information locked up in long-term memory. Among devices used to aid in future recall are mental pictures, emotional intensity, word associations and use of multiple senses.

These techniques are often put to practical use in our everyday surroundings. Anybody who has ever been in the vast O'Hare airport parking garage in Chicago has probably chuckled at how they remember where their car is parked. Instead of using alphanumeric location indicators, such as "Parking Deck C, Level 2, Section 11," O'Hare indicates "Chicago Bulls, Michael Jordan, Red Section." A traveler returning from a trip several days later probably would probably struggle to remember something like "C-2-11" and be more likely to think, "Oh yeah, I was in the Chicago Bulls Section, with Michael Jordan, and Red."

Chunking Information and Organizing Menu Structure

Using what we know about short and long-term memory, we can apply the following strategies to maximize the effectiveness of a program's menu system.

• A menu should ideally have no more than seven items on it. If a menu has more than seven items, see if it can be split logically into a higher-level menu and a sub-menu. This helps students remember which menus contain certain items.

• The order or placement of menu items should match the structure of the tasks.

• If there is no sequence associated with menu items, place the most commonly used options at the top of the menu and least-used items on the bottom.

• Sub-menus should have titles that reflect the selected option from the previous menu. This serves as a simple reminder of where they've been and how to get to this menu again in the future - without taxing their memory. In web-based programs the use of "bread crumbs" are often used, which are simple text indicators of the user's current location (e.g., "Home >> Objection Handling >> Valid Objections")

Using Mental Models or Visual Metaphors

A mental model or visual metaphor is the internal picture we create to help us understand how things work. Even though we are not conscious of our mental models, they help us to use computers effectively. Similar to models, designers use visual metaphors to take advantage of what we already knew when helping us understand something new.

A good example of a visual metaphor is the directory structure of a computer as presented by MS-Window's Explorer program. While the computer actually stores files and data haphazardly on a its hard drive, the visual metaphor presented to the user is that of file folders and a vertical ordering system.

This metaphor gives an artificial but clear sense of order to the system. As users we imagine that our documents are being held in these little folders, and that there is some kind of "depth" to them. We even use this model in our everyday language when we say things such as "It's not in that folder, move up one level" or "I can't remember where I put that file. I must have buried it somewhere."

Mental models and metaphors, however, are still subject to short-term memory restrictions. Most users begin to get lost when their model contains more than three layers or paths. Imagine a training program that has a Main Menu (the first level) from which students gain access to a specific lesson (the second level), and eventually click on a hyper-link called "More Information," which displays some additional text (the third level). At this point, most students will still have a clear understanding of where they are in the program, and how to retrace their steps, if necessary. But if students are once again presented a link for more information, such as a "Case Study" from within the "More Information" section, they will begin to lose track of their location or the relationship of the on-screen content to the overall lesson.

Don't Overload the Sensory System

The human sensory system processes all external stimuli, and it can be easily overloaded with too much stimulation. Information overload can occur even from background noise or peripheral images and animation. A multimedia program that plays continuous background music or repeats a complex animation on a screen to engage the user is just as likely to distract him or her. In reality, this type of overuse of visuals or "eye candy" can conflict with the processing of more relevant content.

Using Multiple Access Points

A simple way to relieve the burden on the users' memory is to provide multiple ways by which they can locate and access the content. Common methods are described below.

• Main Menu. The primary access point is always the program's Main Menu, which should be well organized and descriptive. Rather than using generic names, such as "Lesson 1," "Lesson 2," use descriptive headings such as "1: Overview to Customer Service" and "2: Dealing with Difficult Customers."

• Bookmark and student history. A bookmarking system enables students to exit from any screen in the program, and upon reentering at a later date, resume exactly where they left off. This tracking information is often stored in a student history file.

• Index. An index of key topics or of all learning objectives helps users find specific information. A well-indexed system will enhance any training program's subsequent use as a just-in-time support tool.

• Keyword search. The keyword search enables students to type in a word and have the program scan the entire textual contents for all occurrences. While a very powerful feature, a keyword search only looks at on-screen text and cannot identify information presented as audio narration.

• Site map or content map. A visual representation of the order of the topics in the entire program, or content outline, is called a site map. Typically, it graphically displays the entire menu system, extending down to individual learning objectives.