Maggi Rohde (maggi@intranet.org)

SI 609: Computer Interface Design Spring 1999

References | Endnotes 

Computers are a big mystery to most people. Users don’t know how computers work. Luckily, most of the time this doesn’t matter; users only have to know how to interact with the computer, not how the computer does its job. The interface provides the communication mechanism between the user and the computer. As Terry Winograd says, "Interface devices… are the inevitable embodiment of software for the user." (1) As long as the user can understand and communicate with the computer’s interface, she will be able to complete her tasks effectively.

But while computer interface designs have become better and easier to use, there is still a segment of the population which has been left out: young children. No general user interface has effectively addressed the needs of children under the age of seven. Each computer game or educational program created for children has a new interface; some are better than others, but there is no consistency or continuity between applications. Applications for young children continue to rely on text, when most individuals in this age group do not yet know how to read. And no interface provides a safe and child-proof environment in which children can explore the computer. By applying the guidelines of developmentally appropriate practices for young children to the principles of computer interface design, such an interface can be created.

Child development theory, starting with Piaget, espouses the idea that children move through levels of cognitive processing. Children begin learning through the manipulation of concrete objects, then move to visual representation of those objects, and finally to abstract representations such as words or numbers. (2,3)

Knowing that young children best understand concrete objects has led some researchers to question whether computers are developmentally appropriate for young children, since computers are not concrete. Some researchers continue to claim that using a computer, like watching television, is bad for young children. (4)

But most early childhood professionals agree that computers are very different from television, and that the interactive nature of computers promotes learning. "Children can control the pace and activity and make things happen on computers," says child development specialist Bruce Perry. "They can also repeat an activity again and again if they choose."(5) Frequent playing of computer games has been shown to increase perceptual, motor and information processing skills in kindergarteners.(6) The National Association of Young Children endorses computer activities for children as young as age three or four, give or take a year for normal variation in child development.(7) "What is ‘concrete’ to the child may have more to do with what is meaningful and manipulable than with physical characteristics," say Clements and Nastasi, notable names in the field of computers and young children. (8)

This paper was written to look at the existing computer technology for children, as well as to create a visual and textual model of a possible interface design for young children. First, it will examine the physical space in which children use their computers. Second, an investigation of input devices will determine which kinds of tools are best suited to the needs and abilities of young children. Finally, the way children use computers, in addition to a consideration of their developmental needs, will provide the basis for the design of a new interface through which young children can independently manipulate and explore their computer environment.

Several attempts to create a physically child-friendly computer environment have already been made. Schools, if they allocate the financial resources for it, may invest in computer stations such as the HACH Computer Learning Centers.(9) These stations prominently feature the computer monitor, with a large surface in front for the mouse or other pointing device, and the keyboard off to the side and the CPU safely stored in a lockable cabinet. Some setups include a touch-screen interface. This setup isn’t significantly different from putting the computer’s components on a standard classroom table and stowing the CPU underneath, but it does provide a wheeled, enclosed cabinet for the various pieces of the system.

Another recent design for homes or child care centers is the Little Tykes’ Young Explorer (10), a child-sized, plastic-encased desk/monitor/keyboard combo designed for children aged 3-7, with a CPU cabinet and enclosed space for all the computers’ cables. There are obvious restrictions with such a design: the monitor is only 14" in diameter; the keyboard is a membrane-style design, which means users can spill juice on it and not worry about it being damaged, but its usability is severely hampered; and the mouse pads are permanently affixed to the right and left of the keyboard, preventing a large pad being placed in the middle where most of the action would be for a young child.

One important consideration when setting up a computer workstation for children is that their bodies are still growing and changing at an incredibly fast rate. A study by Cornell University in 1999 looked at 95 students using computers in elementary school; the results showed that all of the computer workstations were unsuitable for their users, and 40 percent of the students used workstations which put them "at postural risk." (11) Workstations must be designed to support young children’s muscular and skeletal development.

In any computer environment for young children, it is advantageous to only have the input and output devices within reach of little hands, with the CPU safely out of reach. One aspect of children’s computing which has not yet been successfully addressed is the frequent switching of CD-ROMs. Children’s games and educational software are so graphic-, sound- and animation-intensive that they take up a great deal of storage space, and thus must be run from a CD-ROM disc rather than from the hard drive. The fragile CD-ROM tray and the CD itself are easily damaged by eager little hands; the less a child must deal with disk-switching, the better! However, as the cost of storage space continues to drop and the standard size of a computer’s hard drive continues to climb, children’s games may be able to be loaded onto the hard drive and the disk-switching game can end.

Input devices designed for young children have a few key features:

• Ease of use. Simplicity is the best idea with young children. Most children’s input devices have fewer buttons than their adult equivalents. Many are color-coded to help direct the user’s eye to the appropriate moving parts. Manipulation of the input device should be easy enough to learn quickly, but challenging enough to encourage developing motor skills.
• Appropriately sized. Whether this means smaller (for smaller hands) or bigger (for less dexterous hands) seems to be a matter of some contention, and no published studies have been done to determine which one is better.
• Durable. Children are hard on their toys. If the interface designer creates a tool to be used by a child, it’s going to get some hard use.

Most manufacturers take all three of these points into consideration when designing hardware for young children.

While they may not pick it up as quickly as older children or adults, young children are certainly up to the task of using a mouse. One study, conducted at Durham University in 1991, showed that after several brief training sessions with a mouse, preschool children perform to the same standard as equally novice adults. One study examined the difference in accuracy between pointing and dragging abilities in young children, and found that young children are better able to point than drag (12), but this test only covered the experiences of novice mouse-users over the course of a single day. According to the writer of the Durham study: "Observations of the preschooler who had prolonged practice suggest that even the youngest children can approach levels of performance on these tasks that are very close to those of expert adults." (13)

The size of an average mouse doesn’t seem to be a problem for young children. The Durham study provided a smaller mouse for preschool children, but "they had no particular difficulty with the larger instrument once the general skills had been acquired." (14)

One common unresolved with the mouse was running out of space on the table for the mouse to run. That is, as the user moved the mouse on the table to make the pointer move on the screen, inevitably the user would come to the edge of the table and would have to "strategically reposition the mouse on the mat (without moving it on the surface itself)…" (15) Young children often couldn’t figure out what to do in this situation.

To deal with this problem in recent years, a trackball has replaced the mouse as the favorite pointing device for little hands (although child-style mice, such as the Winnie-the-Pooh mouse by Delta Millenium (16), are still on the market). Trackballs can not "run out of room," since the ball is on the top and is moved with the fingers instead of moving the entire device.

One trackball option is KidTRAC, a trackball for children ages 3-12. (17) "Our research shows that young children have difficulty using a mouse, but at the same time, parents only want to buy a pointing device for their children that they too like using," says John Cahill, Vice President of Marketing for MicroSpeed, the designers of KidTRAC. (18) It includes a 2.25" diameter ball for fingertip control and three primary-colored buttons, in addition to an industrial-strength design to withstand child use.

Another option is Microsoft’s EasyBall, designed for children ages 2-6. It only has a single button and a bigger, fatter ball. (19) EasyBall’s designers conducted a year-long study with 50 children and 15 different pointing devices, after which they determined children worked most effectively with a trackball.(20) The EasyBall is a good option to use with computers which are only used by young children, such as in day care centers or libraries, or as a second pointing device on a family computer.

There are also drawing tablets designed for children, such as KB Gear’s Sketchboard (21) or the Little Tykes SkidDoodle. (22) However, if the function of the computer is to help children do things they wouldn’t normally be able to accomplish without it, a drawing tablet may be unnecessary or even detrimental. Young children have a difficult time manipulating a pencil in real life; using one on the computer would make their task more difficult, not easier. Children who want to practice drawing or writing skills are better off using crayon and paper.

One study of children and pointing devices included a game controller, such as those used by Nintendo games. The study showed that children were very adept at using the game controller as a pointing device. Currently, however, few computer games designed for young children on the computer use a game controller, so it is difficult to judge whether young children prefer using a game controller to other devices like a trackball.

Keyboards designed for children are often done in bright colors, such as the KidBoard by Web Child (23), or labeled with pictures to help children remember letter names (an apple for A, a bear for B, etc.). Other modifications seem less appropriate: the LittleFingers keyboard has been resized to a smaller scale for little hands (24), with the reasoning being that smaller keyboards fit smaller hands. This reasoning is only appropriate, however, if the hands in question are learning to touch-type. Hunting-and-pecking is just as easy with a big keyboard as with a smaller one, and it could quite possibly be easier. A regular full-sized keyboard is probably just fine for young children who won’t be using it very often anyway.

Durability, however, is another consideration. A standard keyboard will not withstand multiple spills on a hard floor, while children’ keyboards are designed for just that. The KidBoard has a lifetime guarantee. Depending on the environment in which the computer is to be used, an extra-durable keyboard might be worth the purchase.

There are several software interfaces which adults can install over a standard operating system to restrict the access of young children to local files. The Apple Macintosh has one built-in to its standard OS, AtEase. Some products, such as Edmark’s KidDesk Internet Safe (25), even make the interface more fun and child-friendly at the same time.

But no existing interface has attempted to go beyond the familiar desktop metaphor with its file folder icons. Children of preschool age do not understand many of the aspects of a desktop setting because they don’t work at desks themselves. Some early elementary classrooms no longer use desks.

Terry Winograd and Philip Tabor discuss the way in which an interface designer works with "interface genres," such as a word processing program, in the same way an architect works with architectural genres, such as a Gothic cathedral. (26) Designers are influenced by the ways in which their predecessors have done things. But when designing for children, the designer cannot allow herself to be trapped by the parameters of adult genres. An interface designer who wants to develop a computer interface specifically for young children must discover and explore a more appropriate metaphor than the desktop.

Another problem with current software interfaces for children is that they still depend heavily on communicating with the user through text. Most children do not start reading sentences until early elementary school. An interface designed to be used by young children should take advantage of the memory speed and storage capabilities of contemporary computers by using graphics and speech whenever possible, in addition to (but not necessarily in place of) text. Several studies have shown that children have strong positive reactions to verbal communication from computer software. (27,28,29,30)

The purpose of the interface. The primary focus of a user interface designer is determining what the user wants to do. (31) The purpose behind a young child using a computer is not to accomplish a task. It is to provide an additional environment in which they can explore, learn and play. Thus, a child’s computer interface will be very different from an interface targeted at adults.

It is important to keep the interface as general and open as possible, without losing focus on its function. Educators agree that drill-and-practice software is of limited use to young children, and that open-ended, child-controlled software is a better source for developmental growth. (32) The same is true with an interface. Fun should be the emphasis; learning will happen.

The user’s developmental stage. Educators and other professionals dealing with children have a set of developmental standards, set forth by the National Association of Educators of Young Children (NAEYC) by which they decide if a product is appropriate for a specific age group or not. Young children need emotional, social, cognitive and physical experiences to encourage development, and interactions with the computer are no exception.

The High/Scope Educational Research Foundation has developed a scoring system by which professionals can rate software and interface tools for children on a scale of "developmental appropriateness." (33) Keeping such standards in mind is important when designing an interface for young children, so that the capabilities of the software do not exceed the understanding of the children for which it is designed. For example, preschool children are considered to be in the "concrete interactive" stage; they do not think in terms of representative or abstract terms. (34) Thus all the elements of the interface must be presented in a concrete, realistic manner.

Immediacy of feedback. When adults make mistakes, they often have negative feelings, such as being stupid, ignorant, unobservant or angry. In contrast, young children make mistakes as a matter of course; they expect it to be an everyday part of their learning process. They are too young to have developed learned helplessness: they will not be discouraged when something they try does not work. (35)

Because of this, however, young children need immediate feedback that they have done something correct. If they do not receive this immediate feedback, one of two things will happen: either they will not realize they have done something right, and so they will not connect the action with the reaction; or they will lose interest and move on to something else. Their attention span is brief; they will not wait for slow computers to load!

One way to prevent children from clicking on everything in sight when the machine is responding too slowly is to employ a forcing function.(36) Similar to the hourglass or wristwatch icons displayed in Windows or MacOS when the computer is busy doing something, a forcing function would prevent a child’s clicks from having any effect when the computer is working on responding to input. The interface designer will not want to rely on forcing functions too often, however, because their use cuts back on the number of possibilities available to a user in an encounter.

Ability to hold the user's attention. Another consequence of a short attention span is that children will eventually lose interest in what is happening on the screen, no matter how fun and engaging the activity is. The interface’s use of sound, movement and speech after a period of no activity will help recall their attention to what is happening and what they can do next.

Perceived and real safety. Child-friendly means child-safe. A children’s interface should never allow the user to wander down a one-way path; there should always be a way to get back to where they were. Help must be readily accessible at all times.

Likewise, there must be a way for adults to protect their files and applications from curious clicking fingers. Parents should never have to worry that their files may be in danger, or that their children might come across private or inappropriate material.

Use of memory recognition cues. Graphic interfaces for adults rely on the ability of human brains to recognize and interpret familiar features of the interface landscape. This is the key to using metaphor in interface design. (37) But young children have very little procedural or declarative knowledge.(38) They can not take advantage of some of the memory-related shortcuts that adults have because the base of knowledge and understanding they have to draw on is much smaller. It is therefore essential in a children’s interface to use a metaphor they can relate to, in order to take advantage of their own innate capability to recognize.

For use alone or with a caregiver. The NAEYC has taken a strong position on the importance of children using the computer with an adult. When children are given guidance and questions for reflection, they are more likely to connect their experience on the computer to previous knowledge. "Teachers can interpret, remark upon and extend children’s abstract thinking and help them develop problem-solving strategies," says Assistant Professor Samaras from Catholic University of America.(39) Adult involvement in computer use also enhances children’s attention span, memory and thinking. (40,41)

Certainly a young child will more often than not be using the computer with the assistance of their parent, teacher or other caregiver. Ideally, however, the computer should become just one more environment in which a child may freely explore, learn and play, without the fear of breaking equipment or damaging someone else’s files. An interface for young children should be designed with this end in mind.

David Liddle and his coworkers at PARC developed a process of interface design when they were working on the Star in the late 1970s. Their steps included:

1. Perform a task analysis – watch the users work.
2. Develop scenarios for uses of an imagined product based on the task they are doing.
3. Create a model of the interface, keeping in mind three aspects:
1. The conceptual model – what the user is likely to think and how they might respond. It is especially important to make sure the conceptual model remains clear, obvious and substantial.
2. The control and command mechanisms, with an attempt to keep them consistent across different applications.
3. How the information is displayed (the least important point). (42)

These steps were followed in the process of writing this paper. The first step, watching the users at work, was performed at a local public library. Three terminals were set up at child-height, with several chairs in front of each computer. Each computer ran software appropriate for a specific age range – preschool, early elementary, and late elementary – with a different choice every day in a two-week cycle. Observation was done over several weeks, with no interference by the observer in the children’s activities. The object of the task analysis was to see how young children handled a computer which was set aside just for them, to be used with little or no supervision.

Step two was discussed briefly earlier in this paper. What do young children use a computer for? Not to accomplish tasks as adults do, but to explore, learn, and play. Thus the possible scenarios for a child’s interface are fairly open-ended. In this case the parameters of the "task" shall be restricted to private home use of a computer (as opposed to a public terminal at a library or school) by children between the ages of 3 and 7. It is assumed that children using the interface will not yet be reading complete sentences.

Step three begins with the task of choosing a suitable metaphor for the design of an interface for this age group. The metaphor will help define the user’s conceptual model of the interface.

A fourth step, usability testing of the interface with children, is beyond the scope of this paper. Designers wishing to prepare for usability testing are encouraged to read the papers listed in the bibliography on testing products with children.

Some children’s computer products use metaphor in a confusing way. For example, the Little Tykes Cozy Coupe Mouse (43) is shaped like a car, presumably to make it more fun for children to use. But a common mistake young children make when using the mouse is driving it like a car: pointing the mouse in the direction they want the pointer to go, rather than keeping the mouse pointed straight ahead. (44) By presenting children with a car-shaped mouse, the designer is encouraging them to make this mistake. Thus, the metaphor is inappropriate for the task at hand.

Another interface tool, designed specifically for use with a single program, is Elmo’s Computer Phone by Creative Wonders. (45) It is a phone-shaped tool in which the receiver interacts with a voice-activated interface; pressing the buttons (which are labeled with pictures instead of numbers) produces an effect on the screen. While the device does allow a young child to "talk" to Elmo, presenting the phone as a means of visual communication (talking to Elmo while watching him on the screen) seems like an inaccurate use of the phone metaphor. Likewise, presenting the buttons on the phone as a way to interact with the screen has nothing to do with the function of buttons on a real phone. Children might even become confused when pressing buttons on a regular phone doesn’t produce the same effects!

Some important considerations when choosing a metaphor to use in the conceptualization of a computer interface include:

• The amount of structure possible with the metaphor. How much does your audience know about the subject of the metaphor? The more they know, the more possible structure the designer can glean from its use.
• The applicability of the structure of the metaphor to the tasks the user will be doing. Is it relevant?
• The representability of the metaphor. What does it sound or look like?
• The suitability to its audience.
• Its extensibility. How easily does it connect to other related metaphors?

The metaphor chosen for use in this project is a child’s playroom (henceforth referred to as Playroom). This metaphor has been used in the past for young children’s software, and seems most appropriate to describe an atmosphere in which "things get done" for a young child. In addition, a playroom is a "home base" for a child, a place where play begins and ends – a safe and familiar place to which she may return again and again. Using a metaphor such as this may help improve a child’s comfort level with the computer.

An adequate amount of structure can be derived from the use of the playroom metaphor. Even a very young child has a room in which she plays and is familiar with many of the objects which may be found there: a bookshelf, a toybox, blocks, dolls. It is a good atmosphere in which to present concrete and recognizable objects – toys – to use as metaphors for computer applications.

What items may be typically be found in a child’s playroom, and what affordabilities do these items possess? The list in Table 2 was compiled after visiting two preschool classrooms and the home of a 5-year-old. Televisions, computers and game systems (such as Nintendo) were not included because of the implied redundancy of displaying such objects on a computer screen.

The next goal is to match up these familiar objects with tasks which may be accomplished using a computer interface.

A very important aspect of an interface is the consistency of control mechanisms across different applications. In the Macintosh OS, for example, the key combinations for copying (apple-C), cutting (apple-X) and pasting (apple-V) are nearly always the same in every application. These key combinations were picked up by Windows and have become just as consistent, with the apple key replaced by the control key.

But there is currently very little consistency of control mechanisms across applications for young children. Occasional consistency occurs between applications created by the same company, such as the Jump Start series (Jump Start Toddler, Jump Start First Grade, etc.); characters and control keys are the same from one program to another. This is a good beginning, but designers could make more and better use of the concept of consistency.

A young children’s interface such as Playroom will certainly be less complicated than one for adults, and as discussed earlier, the kinds of activities they do on the computer are less structured, but there are some basic similarities regarding what a computer interface should be able to accomplish. By comparing the list of tasks a computer interface must be able to accomplish with the list in Table 2, a designer can match tasks with what seems like an appropriate tool (Table 3).

In Playroom, the pointer is in the shape of a hand. This is the child’s entry point into the room. She can gesture at (point) or grab (click) things that interest her – without any adults telling her "No!" which will almost certainly be a great delight for her. The shape of the pointer will change and animate as it passes over things the child can do, such as changing to a hand holding a crayon when it passes over the note pad, or a hand turning pages when it passes over the bookshelf. Studies show that animated icons are very useful in conveying a possible action to children. (46) Most items in Playroom will come to life when the child passes the pointer over them, and subside if the child goes on to some other item.

A simple metaphor for beginning the day is turning on the light. Playroom begins just that way: the light comes on, the room is illuminated, and the child is ready to explore. If more than one child uses Playroom, the computer will offer their names and ask who is entering the Playroom. When the child is done, she may click on the light switch, the light will go out, and the computer will shut down.

A special adult interface is accessed by pressing a particular key configuration on the keyboard; it also allows adults to exit the interface and reboot the computer using another interface.

Applications in the Playroom are represented by toys. To aid children in grouping applications together with similar content, the toys are organized around the room in various places: driving games are represented by a toy car; animated books by the bookshelf; writing and drawing applications by drawing tools on a table; and so forth. Toys are sorted into preexisting categories by the parent or adult supervising the software. Unsorted toys are put in the toybox; miscellaneous toys which do not seem to fit into any particular category can be left there.

When a child clicks on the toybox or any other group of toys, she is presented with a selection of discrete toys, each of which represents an application. As with other items in the Playroom interface, the toys animate when the cursor is passed over them and held there for more than a second. Text, speech and familiar characters will pop up to help the child identify what the toy is used for.

For example, suppose a child wants to use Winnie-the-Pooh’s Card Maker application. The child’s parent decides that Winnie-the-Pooh is a writing-and-drawing kind of program, so he assigns the application to the Writing and Drawing category. When the child enters the Playroom and clicks on the table with the crayons and paper, she gets a close-up view of the table, which includes toys representing applications which have been put in the Writing and Drawing category. Perhaps a word processing program is also in this category; it might be represented by a stack of stationery or a pad of paper and a pencil.

The Winnie-the-Pooh program might be represented by a smiling Winnie-the-Pooh reading a greeting card. When the child passes her pointer over the toy, it briefly comes to life, beckons to the child and speaks to her in a Winnie-the-Pooh voice, inviting her to make a card. If the child clicks on the toy, the program will launch.

Most programs for young children include a "guide": usually a cute animal or other creature who directs the child through the program and remains as an ever-present assistant. It would be even more useful if the same guide could remain with the child across several different applications, and if the child could choose the identity of their guide from a variety of options. In Playroom, such options will be available; the default guide will be a stuffed animal which waits on the rocking chair for the child to "pick it up" and bring it to life.

Online help, such as the guide, must be an implicit part of the interface, but it shouldn’t get in the user’s way. The Playroom guide is an animated creature, complete with sound and a characteristic attitude. When the child clicks on the guide, it will come to life, talk to her, and suggest what actions might be taken at this time. If the child ignores the guide, it will slowly stop moving, becoming less and less "alive" to keep from being a distraction, until finally it becomes a stuffed creature again – until the child clicks on her guide again. The guide will be active across applications to provide interface assistance. Collaboration between the Playroom designer and other software companies could possibly allow application-specific help as well.

Studies show there is less gender variation between boys and girls at this age than in later years, but children on the older end of the user group will probably show some preference for certain play styles, colors, and familiar characters. It would make sense to allow the child to set the parameters of their guide, perhaps with help from a parent. Users could purchase additional software add-ons so that trademarked character guides such as Tigger or Elmo might be added to the interface as time passes.

Whenever the child uses an application which creates a file, the file is saved in the child’s basket, which sits on top of the bookshelf and is labeled with the child’s name. Grabbing the basket presents the child with animated toys representing each file. When the child grabs a toy representing a document, she is asked if she wishes to change the file, print the file or throw the file away. This simple file interface should suffice for the needs of a young child.

The more control the user has over her interface, the more satisfied she will be with her experience in it. In the Playroom, a child can change the colors and textures on the curtains, wall and rug simply by clicking on those places. As the child passes her pointer over the wall, it will become a hand with a paintbrush, ready to change colors. A click will bring up a row of cans of paint to choose from, and a big animated sploosh will accompany the selected color change.

Likewise, as the child passes over the curtains, a pair of scissors will appear in the hand, and a click will cut the curtains down, followed by an offered selection of fabrics with which to re-outfit the room. Some children may love this feature; others may ignore it entirely. Its availability will not get in the way of either type of user.

In the process of writing this paper I was strongly reminded of a computer program for children which I played with as a teenager. It was entitled Spelunx and the Caves of Mr. Seudo, made by the team that created the games Myst and Riven. It was an entirely open-ended program, with no goals, no objectives, and no assistance – the user was only supposed to explore the caves. Every nook and cranny of the game was filled with new and amazing things to discover and play with; many things were hidden. It is this sense of open-ended exploration and wonder I wish to bring to the Playroom.

Every object shown on the screen in the Playroom is an interactive toy. Grabbing the clock on the wall shows a close-up view with moving hands, accompanied by a digital readout. Clicking again on the clock causes it to speak the hour. The dollhouse in the corner is fully-functional, with furniture to rearrange and a little animated set of dolls who work, play and interact. Blocks on the shelf can be built into skyscrapers and then knocked down, blown up or driven through with a toy car. Perhaps there is a monster hiding under the bed whom the child can befriend. The possibilities are endless.

The open-ended style of the interface provides a comfortable place for children to explore, play and make-believe. Who knows – they may decide the interface is more fun than their games!

In the end, a child’s experiences on a computer will only be as good as her caregivers make it. Children can gain a great deal of satisfaction by learning to explore their computer environment on their own, but interaction with parents, other children, teachers, librarians and day care workers will enhance a child’s computer play and increase the developmental growth she receives from the experience.

And, as child care professionals are quick to remind us: