International Journal of Artificial Intelligence in Education (2000), 11, 144-162 The Role of Different Media in Designing Learning Environments Allan Collins Northwestern University, Boston College, 135 Cedar St., Lexington MA 02421 e-mail: a-collins@nwu.edu Peter Neville Bricolage Interactive Design, 3925 West Braker Lane, Suite 310, Austin, Texas 78759, e-mail: pneville@bricolage.com Katerine Bielaczyc Boston College, CSTEEP, School of Education, Chestnut Hill, MA 02467 e-mail: kateb@bc.edu Abstract. As a broader array of communication tools is developed, designers of learning environments need a better understanding of what kinds of communication each medium is best suited for. Each of the new media have different affordances and constraints. One of our principles for the design of learning environments is “Render unto each medium what it does best.” This paper is an attempt to state some of what we know about what different media are good for. INTRODUCTION Stephen Jay Gould (1980) is noted in biology for the theory of "punctuated equilibrium." When you look at the fossil record, it turns out there are long periods of stasis and the sudden appearance of new species. The sudden appearance of new species in the punctuated equilibrium view is brought about by rapid speciation in a new environment: a species migrates to a new environment, a meteor crashes to earth, two continents collide, someone invents penicillin, etc. After such events there are rapid changes in biological organisms until a new equilibrium is reached. This view has replaced the earlier prevailing view of continuous evolutionary change. We would argue that the evolution of social systems follows a similar pattern. For example, the modern corporation reached an equilibrium state with the development of General Motors in the 1920s under Alfred P. Sloan. This model held sway in America until competition from Japanese corporations and changes in technology forced major restructuring on to American corporations in the 1980s (that is continuing to this day). Even General Motors has been forced to restructure itself, though it was the last of the large American automobile companies to do so. The buzzwords of total quality management, re-engineering, and the virtual corporation are reflections of the many changes that are occurring in American corporations, because of the changed environment they face. Likewise the theory of "punctuated equilibrium" seems applicable to changes observed in the educational system. A number of writers, such as Eisenstein (1979), Olson (1994), Ong (1982), and Postman (1982) have tried to characterize the shift that occurred with the invention of the printing press as Western society moved from traditional oral culture to literate culture dominated by the printed word. For example, Ong (1982) argues that old people were revered in oral cultures because they were the storehouses of memory, whereas written records came to replace this role of old people in literate cultures. Concerning the other end of the age spectrum, Postman (1982) posits that the growth of literacy contributed to the creation of childhood. Many researchers point out that “study” becomes possible when there are written records, and Eisenstein (1979) describes how written records enabled the development of an “archival research tradition.” Further, universal education is viewed as a product of the printing 144 The role of different media in designing learning environments press (Eisenstein, 1979), and is centered on the major products of literate thought, namely reading, writing, mathematics, and science. Our thesis is that we are starting into a cultural transition of similar magnitude with the blossoming of new communication technologies: video, computers, the Internet, video conferencing, cell phones, fax, etc. all of which are merging into one large network that can reach anyone anywhere. More than just receivers of information, people are producers --gaining access to new technologies to communicate messages of their own. The term "new media" is gradually being dissociated from "mass media” as we expand from simply "media by the few for the many" to "media by the many for the many" (Tyner, 1994). People are gaining new voices, new ways of communicating with the world, and redefining the “communities” to which they belong (Rheingold, 1993). Turkle (1995) points out that it may not be a human that one is chatting with online, even citing the possibility of “making a pass at a robot.” Implications in fields such as science have been profound, as scientists virtually manipulate one-of-a-kind equipment in order to remotely perform experiments, such as Internet-accessible electron microscopes (National Research Council, 1993). The new media have also allowed scientists to form collaborative teams that share virtual workspaces across vast distances, including team members in space. We think these new media will have as profound effects as printing, particularly on education, as we move into a digital culture. In fact, although the transition from oral to literate culture took thousands of years, we expect that major advances in the transition to a digital culture will be felt within the next hundred years. When print culture became dominant, it did not replace oral culture, but formed a synthesis with it. Still today we see many places where oral culture still predominates, even in the United States (Heath, 1983). The new synthesis we envision in education will emerge around five dominant media: face-to-face communication, text, video, computer software, and networks. As systems evolve, these five media are becoming integrated into a single digital communication system. We expect that different people will have different interests and abilities with respect to these media, both for producing messages and receiving them. Literacy with these media can be thought of as “digital literacy” (Gilster, 1997) or “cybercy.” Each new medium in some sense subsumes earlier media. Sometimes the transformation is great, as when text substitutes for face-to-face communication (e.g., letters) and sometimes the transformation is small, as when software incorporates video in its programs. Something is lost, but much is gained in the development of each new medium. In thinking about the design of educational media, our assumption is that all of the different media will play a role in the design of any learning environment. The ability of networks to integrate the capabilities of other media makes it critical to consider what role each should play in the design of networkbased learning environments. As designers of educational environments, it is important to consider this proliferation of media critically. What determines whether to communicate one thing via e-mail, another by multimedia presentation, another on paper, and another orally in person? How do we make the most of the media available to us? Each of the new media have different affordances and constraints (Norman, 1988). One of our principles for the design of learning environments (Collins, 1994, 1996) is “Render unto each medium what it does best.” This paper is an attempt to state some of what we know about what different media are good for. These are our first steps toward a design theory for the new media. Affordances must be seen as more than just the kinds of information a medium can communicate well. Affordances also include the ways that the content is presented, and the effect it has on the audience, and the room it allows for tailoring the impact of one's message. One medium might lend itself to the implication of authority, while another might lend itself more to a sense of personal contact and individual interest. One medium might only have a few different ways of conveying information, while another allows a wide range of variations. As an example, one of us took a trip recently to the Grand Canyon. The Park Ranger gathered visitors together to explain the geographical formation of the canyon. As he spoke, the Ranger spread his arms wide before us as a visual for a timeline: his left hand marked “the beginning,” his right elbow marked the time of the dinosaurs, the tip of his right index 145 Collins, Neville, and Bielaczyc fingernail marked the time of humans. While provocative, neither the Ranger’s careful explanation, direct observation of the Canyon, nor following the expanse of his arms were able to help us to fully visualize the processes that formed the Canyon over millions of years. A video animation may have provided a visual representation condensing millions of years of change into conceivable progressions. Or a simulation environment may have been used to allow us to slow, zoom-in to, and replay change processes, and “test out” other possible geographic events. What would this have been like, in this rustic and natural setting? How would this compare to looking out over the Grand Canyon, in the presence of others who share a similar awe, while observations are discussed? Or the way children imitate the Ranger and spread wide their own arms? What is gained, and what is lost by the various media? In the next section we describe some of the critical dimensions on which media vary. Then we return to the different media and their genres, to analyze how they differ with respect to those dimensions. Finally we compare the different media with respect to each of the dimensions discussed. DIMENSIONS OVER WHICH MEDIA VARY Media vary over many dimensions, which we have divided into four groups, in order to provide a more coherent framework for understanding media. The four types of characteristics we discuss are: 1) transmission characteristics, 2) recording characteristics, 3) production characteristics, and 4) social characteristics. We think these capture the critical features that distinguish the effects that different media have for the purpose of educational design. Transmission Characteristics Transmission characteristics have to do with the relation between the sender and receiver(s) and how the messages are transmitted. We have identified seven dimensions: 1. Bandwidth: Media vary in the richness of their messages. The wider the bandwidth, the more that can be expressed. The degree to which a message can be compressed into bits is a measure of its bandwidth. 2. Interaction: Messages can be one-way communications, or broadcasts, with no interaction or they can be two-way (or multi-way) communications, permitting interactions among participants to take place. 3. Number of Receivers: Both one-way and two-way media can allow single or multiple receivers. 4. Negotiability of Meaning: The negotiation of meanings, the back-and-forth determination of the content of a message, or the meaning of terms within a message, can be a critical aspect of whether a message is truly communicated. 5. Control: Control refers to which participant(s) determines the topic and content of the communication. 6. Synchronicity: Synchronicity refers to the degree to which sender and receiver must be present at the same time. 7. Location: Location concerns whether a medium restricts senders and receivers to be in the same place, or whether it is possible to participate in the communication while in different places. 146 The role of different media in designing learning environments Recording Characteristics These characteristics relate to the records that are produced by most of the newer media. We have identified six dimensions with respect to these records: 1. Permanence: Media vary in terms of their permanence, or their ability to be preserved and used at a later time. 2. Reproduction: Reproduction concerns the ease with which copies can be made of an artifact produced in a particular media. 3. Distribution: Latour (1986) emphasizes the importance of mobility of records, which together with reproduction, makes wide distribution possible. 4. Modification: Records vary in the difficulty of modifying them after they have been produced. 5. Navigability: Media differ in the ability of people to move around to get to particular places in the record. 6. Surveyability: Closely related to navigability is the ability to survey the entire record in order to pick out the parts that are of interest. Tables of contents, headings, and indexes are designed to facilitate this capability. Production Characteristics We have identified three dimensions with respect to producing messages: 1. Ease of Production: Media vary widely in the skill and technique needed to produce them. 2. Production Costs: Like ease of production, costs of production vary for different media, though they are still rapidly falling for the newer media. 3. Specialization: Some media have spawned a variety of different production roles, whereas others have not. Social Characteristics We have identified four different dimensions relating to the social aspects of different media. 1. Involvement/Emotional Distance: Media vary in the degree they foster involvement among receivers as opposed to emotional distance. 2. Author Visibility: For some media the author(s) of the message are visible and for other media there is little or no authorial presence. 3. Credibility: Media vary as to the degree receivers accept the messages as true or authoritative. 4. Isolation/Sociability: Some media foster social interaction whereas others foster social isolation. Where different media fall on these dimensions determines the kinds of messages the media are most effective in communicating. In more technical terms they determine the affordances and constraints of the different media. In the next section we discuss in more detail how these dimensions play out in the different media and genres. Then we compare the different media with respect to each dimension. 147 Collins, Neville, and Bielaczyc AFFORDANCES AND CONSTRAINTS OF DIFFERENT MEDIA In this section we discuss each of the five media introduced in the first section, that we think will have an important role in education. We will consider different genres of the media that have different characteristics. Face-to-face Communication Face-to-face communication involves many kinds of interaction between speakers and listeners. Speakers can tell stories, explain ideas, ask and answer questions, watch their listener’s body language, etc. Listeners can interrupt speakers and take the floor with questions, emendations, contradictions, and syntheses. Because of this high bandwidth interaction, face-to-face communication is very good for conveying complex and ambiguous messages -- even messages that the speaker is not aware of. Meaning negotiation is facilitated through interaction between the speaker and listeners, such as questions, puzzled looks, arguments, etc. There can be multiple listeners, as long as they are together synchronously and in the same location. But compared to other media, there can only be a few people who hear a particular idea through face-to-face communication. As the number of listeners increases, the speaker tends to control the interaction by lecturing, and discussion becomes difficult. In small groups one or two listeners can control the interaction by asking questions, but this tends to undermine the structure of the speaker’s message. When listeners share a common background, this is fine. But usually it is best to strike a balance between a speaker structuring the message and interacting with listeners. When there are so many listeners that interaction is severely limited, then all the advantage of face-to-face communication is lost, and video presentation becomes more appropriate. A major limitation of face-to-face communication is that it produces no permanent record, so there is nothing to reproduce, distribute, modify, navigate, or survey, unless some kind of recording is made of the interaction. This means that if something is forgotten, it cannot be recovered. If a good idea is produced, it cannot easily be distributed or studied. Much that is learned is simply lost. Face-to-face communication is easy to produce, but since it involves humans (e.g. teachers), it is very costly to produce, and becomes more so over time as compared with technology-based communications, such as books or interactive videos. In another sense it is inexpensive to produce, because ‘talk is cheap;’ it is just that expertise is expensive. We have very little specialization with respect to speech, though clearly some people, such as Martin Luther King, are masters of the medium. In general people do not have speech writers and editors for their talk, though it may be growing with the new recording technologies. Face-to-face communication is very involving, as long as there are not too many listeners, which cuts down on the interaction. When the speaker is visible, as in face-to-face communication, then the credibility of the medium depends entirely on the credibility of the speaker. Face-to-face communication is the medium that does most to eliminate isolation, and bring people into a community. Our analysis of face-to-face communication is summarized in Table 1. Some of the genres that are particularly relevant to education are lectures, discussions, debates, tutoring, coaching, asking questions, and answering questions. Lectures can reach many listeners, but they involve the least interaction and hence are least effective for conveying complex or ambiguous messages. In discussions and debates control of the interaction passes among the participants, and what is learned evolves from the interaction. Tutoring and coaching are highly interactive, but usually the tutor or coach retains control of the interaction. By asking questions, a speaker can find out what the listeners know and what they have understood, and still retain control of the interaction. But when listeners ask a lot of questions, the speaker loses control, which may lead away from the topics the speaker wants to cover. 148 The role of different media in designing learning environments Table 1. Characteristics of Face-to-Face Communication Transmission Recording Production Social high bandwidth highly interactive few listeners meaning negotiated variable control synchronous co-location no permanence no reproduction no distribution no modification no navigation no surveying easy to produce expensive no specialization involving speaker visible variable credibility fosters sociability Face-to-face communication is critical for conveying certain kinds of messages, particularly those where interaction is necessary to ensure that listeners understand what is being conveyed. This can be assessed by asking questions, watching listeners, or by evaluating the listeners’ responses. Often the speaker may not quite know what they are trying to convey, and the meaning is constructed through the interactions of speakers and listeners. This is particularly common in tutoring and coaching. Hence, face-to-face interaction is effective for conveying tacit knowledge and ambiguous messages, and constructing shared understandings. Text and Pictures Writing dramatically changed the nature of language interaction in a number of ways. Receivers of text messages (i.e. readers) no longer needed to be in the same location at the same time as the author; in fact, any number of readers might live in distant lands centuries later. Readers cannot directly interact with the author to negotiate the meaning, but they can reread the messages over and over till they think they understand. The messages are low bandwidth, which tends to distance the reader from the contents of the message. The author completely controls the contents of the text, but the reader controls the interpretation. The great innovation of writing is the recording of language. This means that the discourse can be permanent, easily reproduced with the invention of printing, and distributed all over the world. Once printed, it is not easy to modify. Better than any other medium, text can by surveyed by the reader, particularly with the help of a table of contents, index, and headings, which were products of the invention of printing (Eisenstein, 1979). The reader can navigate easily through text, locating those passages of most interest or relevance. Eisenstein (1979) argues that the invention of headings changed the very way we organize the world. Text is more difficult to produce than speech. The difficulty of producing it slows the author down and tends to make the messages more thoughtful than speech, as Scardamalia and Bereiter (1994) claim for Knowledge Forum, their online writing environment. The cost of production is not nearly so great as for software or video, and while there is some specialization, as between authors and editors, writing does not have such clearly defined roles as video production. 149 Collins, Neville, and Bielaczyc The author is for the most part invisible with text, which adds to the distancing effect. However, very often in publishing there is an attempt to make the author more visible, in order to draw readers back to that same author. The credibility of a text mainly derives from the source, so that books and journals have an air of authority that leaflets and tabloids do not. But the particular publisher (e.g. New York Times) or the particular author (e.g. Rush Limbaugh) greatly affects the credibility of the text produced. Text is notorious for isolating readers from other people, since it is very rare that reading is a social occupation (Postman, 1982). Our analysis of text is summarized in Table 2. These characteristics of text make it good for representing difficult ideas that need thought and repeated inspection, such as equations, principles, diagrams, maps, theories, arguments, and definitions. Ong (1982) claims that text supports the production of lists, and we would add that this is true for other “epistemic forms” (Collins & Ferguson, 1993), such as tables, hierarchies, stage models, axiom systems, constraint equations, etc. Writing down ideas makes them easier to evaluate and challenge, and thus to be modified and refined over time. This was critical to the development of science. Latour (1986) argues that it was the invention of “immutable mobiles” that was critical to the development of science, focusing on the permanence of the records and their distribution. Until an idea is written down, it is slippery, and it cannot be studied (Ong, 1982). There are two genres of writing that have particular affordances worth considering: narratives and arguments. Narrative reflects the way that events unfold in the world. People remember stories better than other text structures and in fact it is possible to embed arguments in stories, as in fables and parables, in order to aid their memorability. We would argue that narrative form tends to lower the critical stance of the reader, so that the ideas come in without being questioned. Argument has its origins in theories of persuasive rhetoric developed by the Greeks and Romans, but it came to full flower in scientific writing. Postman (1982) argues that the distancing effect of writing supports rational argumentation, and hence to more considered decision making and ultimately to the development of non-intuitive theories and ideas about the world. Table 2. Characteristics of Text low bandwidth not interactive many readers meaning interpreted author control asynchronous located anywhere permanence easy reproduction good distribution no modification easy navigation easy surveying harder to produce inexpensive little specialization distancing author invisible variable credibility fosters isolation Transmission Recording Production Social 150 The role of different media in designing learning environments Video and Film Video first arrived at the beginning of the twentieth century in the form of film. Later near midcentury television was developed and in recent years we have had the development of videotape, videodisks, interactive video (with the development of computers), and video conferencing (with the development of networks). Until video can be easily transmitted over digital networks, we will not see the full flowering of video as a medium. This section will focus on film, television, videodisk and videotape, treating interactive video under computers, and video conferencing under networks. Video is a high bandwidth medium, where the number of viewers is essentially infinite. It does not support interaction (except more recently through interactive video and video conferencing), and hence does not allow for negotiation of meaning. Control is in the hands of the producer of the video, and it, along with face-to-face communication, are perhaps the most manipulative of the media. Video can be seen by people in any location at any time. Film, videotape, and videodisk provide recordings of video. Videodisk is the most permanent of the video media, and unless digitized, most of the films and tapes will be lost. Videodisk also is easiest to navigate, since it is possible to jump around fairly easily to different places in the video. Videotape is the easiest to reproduce, and hence has become commonplace in homes, but it is more difficult to navigate in order to access places in the video that are of interest. In general it is very difficult to survey the contents of a video, though various researchers, such as Stigler and Hiebert (1997) have been developing methods for indexing videos, so that specific sections can be located easily. This in some sense parallels the development of techniques for surveying texts with a table of contents, index, and headings. Video is becoming widely distributed through video stores and eventually over networks. It is difficult to modify video, but a variety of video editing tools are becoming available on computers. It is only in recent years with the development of inexpensive video cameras, that video has become at all easy to produce. As these video production cameras and tools become widespread, we expect that video production will become as necessary a skill as writing, but more difficult to execute well. The cost of video production is very high professionally, but is falling as new tools become available. Video production is the most specialized type of media production, with tasks in film making often being divided between camera operators, directors, producers, editors, and managers of lighting and other effects. Video is a very involving medium, so that it is very good for conveying emotion and showing events as they unfold. The emotional content of video is usually heightened by the use of music and sound. Because of its realism and high bandwidth, it is ascribed more credibility than is warranted, given the selectivity of what is shown. But there is a sense that pictures do not lie, as verbalized in the expression, “Seeing is believing.” The producer is usually invisible with video, though there are recent attempts in the film and television to make the director known to the audience, following the book publishing tradition. Video is not so isolating as text, since there is a tradition of people watching movies and television together, but it does take people out of the community and Putnam (1995) argues that television has led to a decline in civic participation. Our analysis of video is summarized in Table 3. Video is an excellent medium for showing events and processes as they unfold. It preserves spatial relations and the look and feel of processes. The use of voice over with video makes it possible to explain what is happening and why, at the same time it happens. This ability is critical for remembering and making sense of complex processes and events in the world. For example, a video can show a teacher interacting with students, while voice over by the teacher explains the thinking behind the actions taken. Three of the genres of video (live action, animation, and talking heads) have very different affordances for education. Live action shows events and processes in their fullest form and allows the viewer to see and recognize objects, people, and places as they participate in events. Animation makes it possible to focus attention on critical elements, and even to make the invisible visible by showing, for example, the center of mass of a moving object or blood 151 Collins, Neville, and Bielaczyc flowing through the body. Talking heads allow us to see the authors of ideas and to use the cues that face-to-face communication affords. Table 3. Characteristics of Video high bandwidth not interactive many viewers meaning interpreted producer control asynchronous located anywhere permanence easy reproduction good distribution little modification moderate navigation difficult surveying difficult to produce expensive much specialization involving producer invisible high credibility some isolation Transmission Recording Production Social Computer Software Computer software, while incorporating video and text, focuses on the interactive element missing from the earlier technologies. While computers are not as understanding as humans, they do bring a range of capabilities to their interactions that humans lack (Collins, 1996) including realistic scenarios, simulation, animation, immediate feedback, and traces for reflection on processes. Thus they provide a new kind of interaction. The bandwidth is variable, depending on how much text is used, but it is increasing as video is used more and more. The number of receivers is potentially infinite, because software can be copied easily. There is little or no negotiation of meaning possible with current software, but this may change over time as more sophisticated software is developed. Just as with human interaction, control can be kept by the software or turned over to the user, depending on the design of the author. There are no constraints on location, and users interact with the author asynchronously, (but with the software itself synchronously). Software produces a new kind of permanent record, i.e., traces of human interaction, in addition to the text, sound, and video embedded in the software. In general software is very easy to reproduce, except to the degree measures are taken to prevent reproduction. Software is widely distributed, and modification, though easy, is restricted by almost all developers. Most software is designed to be easy to navigate, but it is quite difficult to survey. Software is difficult to produce, comparable to video. But more and more powerful tools for producing it are always being developed, and many people have learned how to write software. Whether it will become an important skill for all people to learn is still open to question, but there will always be a number of highly paid professional software developers. There is some specialization occurring in the profession (e.g. programmers, system analysts, etc.), but it is not as specialized as video production. It is costly to produce, but when many copies of software are made the costs can be spread so that each copy is relatively inexpensive. 152 The role of different media in designing learning environments Because software is a very interactive and controllable medium, it can be emotionally involving, but most uses of software, such as tools and simulations are distancing. The increased use of video will if anything enhance the involvement of users. Authors are currently invisible to users, except for the rare pieces of software like Myst, where there is some authorial presence in the design and marketing. People treat software as credible and authoritative, though this may diminish as people spend more time in computer environments. Like text, software use tends to be isolating, except for those rare programs that are meant to be used by groups of people. Our analysis of software is summarized in Table 4. Two major innovations of software that we see, particularly in the realm of science, are data visualization and simulation. Software makes data visualization possible, because it combines the ability to manipulate data with the use of video displays. This allows people to see relationships that they might otherwise miss. Software makes simulation possible, because it can run processes with different inputs. Simulation allows them to try out different possibilities and see what happens. Scribner and Cole (1975) have described how unschooled people are unwilling to do this kind of hypothetical reasoning. Data visualization and simulation techniques greatly extend our ability to teach these skills. These two capabilities greatly expand the range of messages we can communicate and are powerful extensions of the way we understand the world. There are two other major effects of software for education: 1) Users can construct objects and processes (e.g. works of art, programs) and see their effects. This gives learners immediate feedback on what they have done, and tools to make modifications easily to improve their work. 2) Software can provide traces of people’s performance on complex tasks. This allows them to reflect on how they did a task and how it differed from the way others, particularly more expert people, did the same task. Ultimately we may be able to record how our best thinkers (a modern day Shakespeare or Newton) work through issues and problems (Collins & Brown, 1988). Table 4. Characteristics of Software Transmission Recording Production Social variable bandwidth computer interaction many users meaning interpreted variable control asynchronous located anywhere permanence easy reproduction good distribution easy modification easy navigation difficult surveying difficult to produce expensive some specialization variable involvement author invisible high credibility fosters isolation Networks The most recent of the new media is the computer network, though the telephone network served as a forerunner. Once video transmission becomes commonplace, computer networks 153 Collins, Neville, and Bielaczyc will in fact synthesize the capabilities of the other media. They can provide face-to-face interaction through video conferencing and all the text, videos, and software that the world produces. Mastery of this medium then will involve mastery of all the other media. This is the most interactive of the media, since it supports both interaction with people and computers, with their very different properties. It is a very high bandwidth medium with the potential for showing the people one is interacting with in one window and live action video in another window. But the bandwidth for human interaction is not as high as in face-to-face communication, so that many facial and auditory cues are lost. The number of potential receivers is high, but for human interaction there are currently severe limitations on the number of sites that can interconnect and the number of people who can be shown. Control and the negotiability of meaning varies with whether the receiver is interacting with other humans or with computers, video, and text. There are no constraints on location, and the medium can be used both synchronously and asynchronously. Web pages, email, and chats are asynchronous genres, whereas video conferences and online forums are synchronous genres. Networks add another kind of record to those possible with computers. When people interact over computer networks, it is possible to keep a permanent record of their interactions. Like computers, all the records that are produced are easy to reproduce and modify. In fact, computer networks make distribution remarkably easy, which will have the profound effect of bringing all the world’s knowledge to one’s fingertips. The same kinds of problems of navigating and surveying material occur with networks as with computers, but are exacerbated by the abundance of materials. This has led to the development of search engines, but they may be losing the battle against the proliferation of information on the web. Some things are easy to produce for computer networks, such as email, video conferences, chats, and even web pages. Other things are much more difficult, such as videos and software. Similarly, the cost of production is equally variable. It seems as if eventually everyone will produce things for the web, at the level of their ability and resources. Some web sites will be produced by corporations, with all the specialization that occurs with text, video, and computers. Other web sites will be produced by young children with enthusiasm and limited resources. The social characteristics also vary with the type of message. Credibility is most at stake with the web, where there are a large number of sources whose credibility is uncertain (Gilster, 1997). Involvement is typically high in chats, MUDs, video conferences, and live action video, whereas text and email are much more distancing. The author is visible with video conferencing, and to some degree with personalized web pages, email, chats, and MUDs, but usually not with videos and software. Networks foster a new kind of sociability (Turkle, 1995), where people interact electronically rather than physically. But there is data (Kraut et al., 1998) that suggests people who rely heavily on computer networks may have less social interaction in the real world. Our analysis of networks is summarized in Table 5. The two most profound effects of networks to date have been 1) to connect people all over the world into communities of interest rather than communities of place, and 2) to support ordinary people, including children, becoming producers of material, as well as consumers. Whether they develop their own web pages, send email, or build imaginary places in a MUD, it is clear that publication is being democratized by computer networks. Networks are changing the relationships between producers and consumers toward the balance that existed with oral communication, before the authority of text, film, and television took hold. But at the same time networks will further destroy the bonds that used to hold local communities together. People have become more able to construct their identities as part of distributed groups (e.g., multinational corporations, professional societies, etc.) and networks can only hasten the demise of the local community, in favor of distributed communities based on shared interests. 154 The role of different media in designing learning environments Table 5. Characteristics of Networks variable bandwidth 2 kinds of interaction many users variable meaning variable control both possible located anywhere permanence easy reproduction easy distribution easy modification variable navigation difficult surveying variable ease variable expense some specialization variable involvement variable visibility variable credibility variable sociability Transmission Recording Production Social A COMPARISON OF THE AFFORDANCES OF DIFFERENT MEDIA In this section we will discuss the evolution of the media with respect to each of the dimensions introduced above. Transmission Characteristics 1. Bandwidth: Increases in bandwidth allow us to combine different representations simultaneously. While face-to-face communication is high bandwidth and text low bandwidth, they both only provide one representation of an idea or situation at a time. Video makes it possible to combine different representations simultaneously with captions, voice over, and split screens. So for example one can see a process unfold in live action on one screen and animation on another screen, while voice over explains what is happening. Computers have extended these capabilities with multiple windows. Ultimately with networks people will work together, while viewing each other in one window and manipulating objects and representations in other windows. 2. Interaction: Interaction was lost as we moved from face-to-face communication to text and video. But it is being found again with software and networks. Software introduced a new kind of interaction, responsive environments, which react to people’s actions. This is most apparent in tool, game, and simulation environments. Networks reestablish a kind of face-to-face interaction, but in a new context, where people can manipulate software environments at the same time. The synergies of combining these forms of interaction have barely been explored. 3. Number of Receivers: The big leap in reaching a larger audience came with text, which could go out all over the earth and into the future. Video extended the reach further, because it is much more accessible to people; i.e. many more watch television or film than read books. Networks extend this reach even further by connecting many people to different resources at the same time, almost instantaneously. 155 Collins, Neville, and Bielaczyc 4. Negotiability of Meaning: Text and video surrendered the ability to negotiate meaning that is so characteristic of face-to-face communication. But it may be returning with software and networks. Software is beginning to provide some ability to negotiate meaning by building user models. Networks go further by offering opportunities to interact with producers of texts, videos, and software. These can occur in online forums, email exchanges, or video conferences. Hence meaning negotiation is returning in multiple guises. 5. Control: While face-to-face communication allowed the listener to take control of the conversation, both text and video entailed sacrificing control to the producer. The receiver cannot change the topic or influence the message in any way. This has changed with software and networks. In simulations and games, users can control what they try to do, with tools they can control what they create, and with the web they control where they go. With MUDs, online forums, and video conferencing, control of interactions has evolved new forms not possible with face-to-face communication, such as people taking on new roles and identities (Turkle, 1995). 6. Synchronicity: Text, video, and software freed people from the synchronicity constraint imposed on face-to-face communication. Now with networks, it has become possible to mix synchronous and asynchronous communications. Synchronicity makes it possible to interact in real time with producers, and asynchronicity allows for extensive production time and an opportunity to revise work. Because networks support both, it becomes possible to interact with the authors of works about what they have produced earlier, which may lead to further revisions of their work. 7. Location: Like synchronicity, the newer media free communication from the constraint of co-location. This makes communication more difficult in that most deictic reference (e.g. use of words like ‘here’ and ‘soon’) is lost. But the gain in potential audience in giving up the co-location constraint has been vast. Recording Characteristics 1. Permanence: Many of the major effects deriving from the invention of writing were based on the permanence of the records, which were studied by people years later and provided documentation for what happened in the past. As Eisenstein (1989) argues, the study of printed texts led to the Protestant Reformation and the development of science.. We are beginning to see a similar development in the use of video for studying complex processes, such as teaching (Ball & Lampert, 1999; Frederiksen, 1992; Stigler & Hiebert, 1997) . Similarly, computer traces of human interactions can provide a new basis for study of human processing (Collins & Brown, 1988). 2. Reproduction: Printing made it possible to produce many copies of a text easily and hence reach a much wider audience. This was crucial to the development of universal literacy. The digitizing of information makes reproduction much easier and practically cost free. So it seems likely that we will see a large increase in the audience that can be reached by digitized media. 3. Distribution: One of the largest effects of networks is the ability to distribute all of the world’s knowledge that has been digitized. The reach of media took a giant leap from face-to-face communication to text, video, and software, which are available in stores and libraries. The leap that occurs with networks will be of similar magnitude. 4. Modification: It is not possible to erase what was said, nor even change a printed text very easily. The advent of digital materials makes it easy to copy and paste them together. This is how lawyers create new documents for a client. But at the same time it makes it easy for students to pass off modified materials as their own with a minimum 156 The role of different media in designing learning environments of work. Still this is the way new products will be created in the future, and we all need to learn how to reuse past works to create new syntheses. 5. Navigability: Text developed resources for navigating through documents, such as a table of contents, an index, and headings. These were lost with video, but with videodisks we are beginning to develop tools for navigating through video. Software has usually been designed for easy navigation, and the web provides new ways to navigate using page layouts and links. That is why browsing has become so common on the web. While people have always browsed through books, they have never browsed through video and software. But browsing is back with the web. 6. Surveyability: Closely related to navigability is the ability to survey the entire record in order to pick out the parts that are of interest. With texts it is often possible to locate what you want easily. We do not have good indexing schemes for video or interactive media, so that they are more difficult to survey. But much effort is going into making video more surveyable (Stigler & Hiebert, 1997).The web provides search engines for surveying the web, but the proliferation of information is making it more difficult to find what you want. Production Characteristics 1. Ease of Production: Face-to-face communication is the easiest to produce, since humans were designed to talk. Writing is more difficult to produce than speech, but advanced societies have attained high levels of writing literacy through education. We may well be going down that same path with video and software, since many activities in the future will require the production of video and software as part of their documentation. More and more children are producing their own web pages, which is democratizing the whole idea of publication. To be literate in the next century, one will need to produce work in all these media. 2. Production Costs: Like ease of production, costs of production are high for video and software and somewhat lower for printed texts. But the ease of producing texts on computer networks, may make them inexpensive to produce and distribute, as we see with web pages. With the proliferation of video cameras, personal computers, and editing tools it is becoming much less expensive to produce video and software. As video and software production becomes universal, they will become much less expensive. 3. Specialization: Video production is so complicated it has spawned a variety of roles, such as camera operator, director, producer, script writer, and video editor. Other media have not spawned so many roles, though writers do rely on editors. Software production, while complicated has not produced such clearly defined roles, though they may develop over time. The history of work has been toward more and more specialization (Drucker, 1995). At the same time, we see more and more children producing their own videos, software products, and web pages. Probably both trends will continue with high-end products produced by teams of specialists and low-end products produced by common people. Social Characteristics 1. Involvement/Emotional Distance: Face-to-face communication is emotionally involving, when it is interactive. Text led to a distancing of people from emotional involvement with events. It promotes objectivity and rationality. Video has tended reestablish emotional involvement, as can be seen by the coverage of news on television. Most uses of software have the same kind of distancing effect as text. But 157 Collins, Neville, and Bielaczyc networks support both the emotional involvement of live action video and video conferencing, and the emotional distancing of text and software programs. So a new balance will be struck. 2. Author Visibility: Face-to face communication makes the speaker visible to the listeners, whereas the author is invisible with text, video, and software. Book publishing and film have attempted to make authors and directors more visible in order to sell books and movies. But other media such as software and television have for the most part attempted to hide the authors. Authors are becoming more visible with the onset of networks. Pictures and biographical descriptions often accompany web pages, and sometimes you can interact with authors via email, online forums, and eventually video conferences. We may even begin to see authors portrayed in videos, much like music videos. High-end products may resist this trend, since they will be produced by teams, but there will be more space to portray the teams if they so choose. 3. Credibility: Media vary as to the degree receivers accept the messages as true or authoritative. With face-to-face communication, credibility depends on the speaker. With respect to text, credibility depends both on the author and the source (e.g., the London Times). Because “seeing is believing,” video has perhaps more credibility than it deserves. Credibility is being undermined in the digital media by easy modifiability and a proliferation of views. This means that credibility will more and more be associated with particular authors and sources, and how much trust they have earned. 4. Isolation/Sociability: As Postman (1982) points out, text tends to isolate readers from other people, especially as compared with the sociability of face-to-face communication. Many people worry that the proliferation of media such as video and computers has tended to isolate people more and more. But networks, like phones before them, are making new kinds of connections possible. Email makes it easier to maintain friendships with people who move away and to reduce the isolation of people confined to their homes or hospitals. Furthermore, people are constructing new kinds of communities using MUDs and online forums and video conferencing. So networks may help to reconnect the people isolated by text, video, and computers, but the study by Kraut et al. (1998) casts doubt on this possibility. Table 6 summarizes our comparisons of the five media. Table 6. Comparison of Different Media Face to face Transmissionhigh bandwidth highly interactive few listeners meaning negotiated variable control synchronous co-location Recording no permanence no reproduction no distribution no modification no navigation no surveying Production easy to produce expensive no specialization involving Social speaker visible variable credibility fosters sociability Text low bandwidth not interactive many readers meaning interpreted author control asynchronous located anywhere Permanence easy reproduction good distribution no modification easy navigation easy surveying harder to produce inexpensive little specialization Distancing author invisible variable credibility fosters isolation Video high bandwidth not interactive many viewers meaning interpreted producer control asynchronous located anywhere permanence easy reproduction good distribution little modification moderate navigation difficult surveying difficult to produce expensive much specialization involving producer invisible high credibility some isolation 158 Software variable bandwidth computer interaction many users meaning interpreted variable control asynchronous located anywhere permanence easy reproduction good distribution easy modification easy navigation difficult surveying difficult to produce expensive some specialization variable involvement author invisible high credibility fosters isolation Networks variable bandwidth 2 kinds of interaction many users variable meaning variable control both possible located anywhere permanence easy reproduction easy distribution easy modification variable navigation difficult surveying variable ease variable expense some specialization variable involvement variable visibility variable credibility variable sociability The role of different media in designing learning environments CONCLUSION Throughout this paper we have tried to highlight the affordances and constraints of the different media that are coming together in digital networks. So why is it important to understand the affordances and constraints of different media in designing learning environments? We think there are three central reasons. Shift in the Focus of Schooling Learning research in the second part of the century has supported a shift from a transmission model of education, to a model based on "social-constructivism." The constructivist view is that people learn best, not by assimilating what they are told, but rather by a process of knowledgeconstruction. Further, in order for individuals to learn how to construct knowledge, it is necessary that the process be modeled and supported in the surrounding environment. Powerful tools can provide support to enable learners to scaffold their own understanding of complex domains and issues. They can give learners the ability to engage in meaningful tasks that authentically reflect the kinds of tasks they will face in the world. The problem is not simply that a simulation might be better to communicate, but that having a still picture provides no way for the student himself or herself to construct knowledge. So, designers need to be aware of what the affordances are, so they know what is enabling learners themselves to construct their own knowledge. As people take more control of their learning, they will choose environments that are most conducive for their own learning. In particular they will choose environments that actively engage them in interesting activities. We would suggest that environments where they are part of a learning community (Bielaczyc & Collins, 1999; Collins & Bielaczyc, 1997) and can interact with people who have interests in common with their own, will be particularly appealing. Perhaps equally attractive will be environments that actively engage them in solving complex and meaningful problems. In any case, people will have much more control over their own learning, and will demand relevant and meaningful tasks, that utilize the most effective means of communication and learning. Needs for Digital Literacy One of the effects of the onset of the information age is to radically change what people need to learn in order to succeed in the new society. Lemke (1998) discussed the need for students to develop “media-literacies,” which will empower them with new ways to communicate with the world. Work is becoming more distributed and groups must be able to coordinate their work across cultural and national boundaries. At the same time, it is becoming more important for scientists and businessmen to master multiple media in conducting their daily work. It is becoming critical for analysts to use data visualization and manipulation techniques to make sense of the proliferation of information. It is becoming essential for advertisers to use multimedia displays and computational tools in order to win over customers. Because technology can carry out the routine tasks in the world, there is less and less demand for people to do routine tasks (e.g., bank tellers, typists, clerical workers, production line workers) and more and more demand for people to do work that requires thinking and problem solving (e.g., analysts, information brokers, technology support). Even jobs that were once considered fairly routine (e.g., secretaries, farmers) have come to require complex information processing. Digital literacy and media sophistication is becoming necessary to succeed in every aspect of life. So it is critical that education focus much of its effort in teaching the new digital literacies as well as the old literacies of reading, writing, and arithmetic. As new technologies in society create demands for educating students in new skills, new media support the teaching of these skills better than more traditional instructional methods. So as the demands on education change, understanding how to use new media to teach new skills is critical. 159 Collins, Neville, and Bielaczyc Constraints on choosing the most effective medium In designing educational environments, there is a tendency to revert to familiar forms for teaching and learning. Given the entrenchment of well-worn educational methods, it is no surprise that the majority of educational software titles emulate the worksheets and didactic style that have come to be equated with education. The design community's familiarity with these methods and the limited understanding of new media's capabilities constrain the approach of much current work. Producing multimedia is an expensive and time-consuming undertaking, and without clearly articulated arguments for selecting one medium over the other, there is a strong tendency to select media based on design efficiency. For example, still pictures might be used where animation would better communicate for understanding. Across-the-board templates regarding where animation, a talking head, a still photo, a map, or text are placed, are often created for all the content in a program, rather than according to the specific information presented in a particular unit or section. As new technologies facilitate production of animation and other new media types, and as the affordances of these media become clearer, we may be able to customize designs to fit the content within budget and schedule constraints. The debate of learning versus playing is an old one, and making learning engaging should be an objective in designing learning environments. However, we currently understand the affordances of media for gaming much better than we do for education, and this makes it very attractive to harness the motivational impact of games for education software. The key is not to stop this practice, but to be able to distinguish affordances for engaging players versus affordances for engaging learners, and that the former does not remove the need for the latter. Further, software media are too often selected according to what showcases technological wizardry or contains the most movement and graphic definition. Again, aesthetic appeal is an important consideration; however we must be careful in including the full range of design considerations. Of course, educational design depends on a great number of issues and constraints, beyond what a given medium does best. Cost, time to produce, time the learner will spend in the educational environment (e.g. museum, classroom) are all critical design considerations. Further, as described by Schofield (1995), once a given design moves out of the design environment and into the context of use, the context of use often raises issues and applications that are difficult for designers to have anticipated. However, considerations of the affordances of media play an important role in design, and the present paper provides a step toward a more formal framework, shown in Table 6. With the proliferation of media, we are faced with a bewildering array of choices in the construction of learning environments, and many more opportunities to make inappropriate choices. Recognizing the influences mentioned above, and tempering them with increasing knowledge of the dimensions of new media for learning, should help us become better able to select the right tools for the job. Acknowledgments We thank Beverly Hunter, Michael Reynolds, and the four reviewers for their comments on a previous draft of this paper. References Ball, D. L. & Lampert, M. (1999). 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