Unless computer-mediated communication systems are structured, users will! be overloaded with ..... devices that work best for them, and to change them as needs and the .... Personal notebooks or files facilitate the conference process by ...
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STRUCTURING COMPUTER-MEDIATED COMIMUNICATION SYSTEMS TO AVOID INFORMATION OVERLOAD Unless computer-mediated communication systems are structured, users will! be overloaded with information. But structure should be imposed by individuals and user groups according to their needs and abilities, rather than through general software features. STARR ROXANNE HILTZ and MURRAY TUROFF OVERVIEW Computer-mediated communication systems (CMCS’s) use computers and telecommunications networks to compose, store, deliver, and process communication. Among the types of systems that come under this heading are electr80nic mail, computerized conferencing, and bulletin-board systems. CMCS’s can provide sufficient speed and vollume for effective communication flow within and between groups and organizations. However, this “solution” to constrictions on the flow of information and communication is not without cost, in a behavioral as well as an economic sense. Computers and related “office-automation” technology can often create as many problems for an organization as they solve. As Kerr and Hiltz have put it, The volume {and pace of information can become overwhelming, especially since messages are not necessarily sequential and multiple topic threads are common, resulting in information overload [IS, SO]. Information overload presents itself first as a problem, then as a constant challenge to be overcome. Intensive interaction with a large number of communication partners results in the mushrooming of the absolute amount of information and the number of simultaneous discussions, conferences, and other activities, that goes well beyond normal coping abilities. [IS] Denning [2]( cogently characterizes one contributing factor to information overload as “electronic junk”frequent CMCS users can expect to be imposed on by unwanted and useless messages. This problem is becoming worse as more systems, and therefore more users, are interconnected by networks like CSNET, USENET. and MAILNET.
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The research on w:oich this paper is based was partially supported by grants from the National Ikience Foundation (NSF) (NSF-MCS-00519, MCS-77-27813. and MCS 812865). ‘The opinions and conclusions are solely those of the authors and do not nwessarily represent those of the NSF. Portions of this paper were presented at the 16th Hawaii International Conference on System Sciences. 0 1985 ACM OOOl-0782/85/0700-0680
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However, on the basis of several years of observing users of these systems, we must disagree with Denning’s prescription for this problem, that “the research community must study traditional (nonelectronic) corn.. munications paths in existing organizations” and “abstract the key properties of successful communications and replicate them electronically” [.!?I.This premise takes computer-mediated systems as automated versions of off-line media. CMCS’s are a new medium with their own advantages, disadvantages, social dynamics, problems, and opportunities. For instance, putting the computer into the communication loop makes new information filtering and handling techniques possible. Indeed, the automation of communication practices developed for nonelectronic media may actually counteract some of the potential benefits of CMCS’s. In this article we present our current thinking on desirable design options and implementation strategies for CMCS’s, and consider information overload, communication filtering, and the total productivity of information workers. It may seem that we are only discussing the subset of CMCS’s known as conferencing systems, but that is not the case. Although most of our examples are drawn from conferencing systems, we believe that many of the distinctions between “simple” store-and-forward message systems and groupcommunication-oriented conferencing systems will become negligible as CMCS’s take on more of the features of full-scale conferencing systems. Among the authors who have dealt with such prospects are Tsichritzis et al., who state, In current message systems, the messages remain uninterpreted . The system delivers the message but does not manage the messages.. . . In order to enhance their functionality, message systems have to interpret, at least partially, the messages they handle. [26] Our argument
is that the computer
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active role in filtering and structuring communication. Palme puts it this way: Systems are often designed to give the sender too much control of the communication process, and the receiver too little control Electronic mail systems thus need to be more database oriented, like some computer conference systems already are. [20]
We would add that CMCS’s should also be designed to foster the emergence of cohesive groups that can exert social control over members’ behavior. In addition to active software roles, there are active human roles that can be played; these roles can to a certain extent be built into the software in the form of special privileges and functions. The body of literature applicable to the topic spans computer and information science, human-factors engineering, management science, and the social sciences. A complete review would constitute a lengthy treatise, and so we restrict ourselves to selected literature on specific points. One study relevant to our topic comes from a surprising source: an examination of crowded dormitory living situations [l] “characterized by frequent unwanted or unmediated social interaction.” A CMCS, like a crowded dormitory, can subject individuals to an excess of communication stimuli by dramatically increasing “social density” or “connectivity.” Overload and the stress it causes can be mitigated if certain structural design aspects of the interaction space are optimized. In dormitories, designs that cluster residents in short hallways (with 20 people or less) were found to be less stressful than those that put larger numbers of residents into a common interaction space: Small groups developed, “residents knew more of their neighbors, and interaction with them was more predictable.” With longcorridor designs, there was “a surfeit of unwanted interaction” and “a lack of protective group structure.” Thus architecture was a key to structuring social interaction to make a densely occupied space feel more like a set of small communities. Analogously, we believe that one of the basic principles of CMCS design should be to encourage relatively small task-oriented groups and communities of interest. The dormitory study also drew on earlier work by Mehrabian [li’] and supported his finding that successful coping with high social density is related to personal “screening” skills: Screeners.. . effectively reduce the stress of numerous inputs by constructing a priority-based pattern of attention to information (i.e., by disregarding low-priority inputs). [They] cope with the high rate of social interaction in the environment in a deliberate and organized manner. Nonscreeners are more likely to become overaroused in situations characterized by high rates of information and are prone to fatigue and psychosomatic components in such settings. [l]
In order to cope successfully with high social density, then, people must be able to screen incoming information. Computer-mediated interaction environments should provide tools that can help users to organize information and set priorities.
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Our tentative conclusions are based on observations, user surveys, and controlled experiments [5, 6, 7, 111, as well as a review of the literature. They can be summarized as follows: 1.
2.
3.
4.
5.
Perceptions of information overload peak at intermediate levels of CMCS use, when communications volume has built up but users have not had a chance to develop screening skills. To inhibit the flow of “useless junk” is to risk the loss of one of the most valuable impacts of CMCS’s-the flow of potentially useful information and ideas among persons with no previous or offline communications links. These systems greatly increase the number of individuals with whom a person can stay in regular contact and the number of activities a person can monitor. For an individual to make an optimal transition from current communication habits to what is possible electronically requires some exposure to the risks of overload. To automate procedures that work for traditional forms of communication, like the telephone or the internal memo, is to ignore the basic fact that computer-mediated communication offers new potentials for filtering and ordering information. Moreover, it is to ignore the strong role that emergent social norms can play in preventing undesirable behavior. To design a CMCS is ultimately to alter a social system. Individuals learn to self-organize communication flows that might initially seem overwhelming. Moreover, different individuals have different needs and preferences. Systems should offer a number of options for information organization and handling, instead of imposing a single solution for all users. Any method for filtering or reducing overload should allow individuals or groups to select their own criteria for valuable communications. Careful evaluation and feedback from users are necessary for gaining an understanding of the kinds of structures or features that are useful for various
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sizes of communication nets and various types of tasks. Users, as individuals and as groups, evolve in their use (ofCMCS’s. In evaluating the usefulness of possible features for avoiding information overload, we must’consider the long-term effects on the social cohesion and productivity of informationexchange networks that the system fosters, and not just the immediate and short-term convenience of individua I group members. An organization’s ultimate success with a system is likely to reflect the degree to which the system is tailored to the requirememts of experienced users. In the remainder of this article, we expand the first three of these points. The main empirical basis for our assertions is surveys, experiments, and observations of users of the Electronic Information Exchange System (EIES), a computerized conferencing system operated by the New Jersey Institute of Technology that is devoted to the design and evaluation of alternative structures for computerized human communication. We have also looked at other CMCS’s, surveyed their users on a more casual basis, and attempted to distill our observations into generalizations for this entire class of computer systems. PERCEPTIONS
OF INFORMATION
OVERLOAD
Information overload has traditionally been defined as “information presented at a rate too fast for a person to process” [23]. IPerhaps we should invent a new term to describe what information overload means in the context of CMCS’s, because here the term refers first to the delivery of too many communications and to an increase in social density that gives individuals access to more communications than they can easily respond to, and second to what might be termed information entropy, whereby incoming messagesare not sufficiently organized by topic or content to be easily recognized as important or as part of the history of communication on a given topic. For either the traditional or the electronic context though, the basic responses are the same. Individuals might 1. fail to respond to certain inputs, 2. respond less accurately than they would otherwise, 3. respond incorrectly, 4. store inputs and then respond to them as time per-
mitted, 5. systematically ignore (i.e., filter) some features of
the input, recode the inputs in a more compact or effective form, or 7. quit (in extreme cases) [23].
6.
Miller [19] found that individuals tend to focus on filtering and omitting (ignoring) information as the primary effective ways of coping at high rates of information overload. So, from a totally different research tradition, we come to the same conclusion as the sociologist who studied social density in dormitories: The need is for structures that will distinguish communications that are probably of interest from those that are probaCommunications Iofthe ACM
bly not of interest; these structures must also be useful for compacting, condensing, and organizing information. Software is only part of the solution, though. Individuals must learn screening skills and develop shared norms about sending behavior so as not to impose unwanted material on others. In one of our longitudinal studies of EIES users, we asked, “Thinking back over your experiences with the system, how frequently have you felt overloaded with information?” The question and scale were chosen to match an earlier study of PLANET users by Vallee et al. [30], so that the results could be compared. This question was asked three to six months after users first signed on line. As Table I shows, the average EIES user “sometimes” feels overloaded. The means obtained for a second sample of EIES users and for users of other systems who answered at a similar cumulative activity level are comparable. Thus, information overload would seem to be a serious and common problem, but not one which is immobilizing for most users. However, these studies also indicate that users learn to cope with information overload after they gain sufficient experience with a system. Individuals in the intermediate ranges of cumulative use would seem to be most susceptible. Among the first sample of EIES users, reported in Table I, 31 percent of those with 20-49 online hours reported “almost always” experiencing information overload, whereas 100 percent of those with 100 hours or more reported feeling overloaded only “sometimes, ” “almost never,” or “never.“’ The same strong pattern of association with activity level persists for the results of the second through the fifth samples. The modal cumulative time category is included in Table I as a reminder that overload is strongly correlated with usage level. Apparently, experienced users develop effective ways of coping with what may initially seem to be an “overload” of communications. (Of course, without longitudinal data, we cannot be sure that there is not an alternative explanation for the observed curvilinear pattern of association between overload and on-line hours; specifically, that users who almost always experience overload quit before becoming experienced users.) The corollary is that beginners tend to overextend themselves, not so much by reading junk mail as by trying to be fully informed on a multitude of activities. This phenomenon is most pronounced in a conference structure, where beginners tend to join all the conferences that sound interesting. When they reach overload, they begin to withdraw from some of the discussions and make use of more sophisticated options for limiting the amount of material they receive. Users can also take advantage of the storage capacity of the computer to arrange for an optimal number of transactions per session. In a prior paper [g], we pointed out that users seem to be driven to sign on often enough to keep their per-session transactions (individ1 Unless otherwise specified. subsequent data about EIES users or references to the “EIES sample” are from this first sample.
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TABLEI. User’s RepottedOverloadExperience Responses are to the question, “Thinking back over your experiences system, how frequently have you felt overloaded with information?”
with the
Sources: EIESI-follow-up questionnaire three to four months after the beginning of system use; 110 scientific and professional users; EIESP-four-month follow-up survey of new users (1983) responses from 140 managers and professionals; COM-four-month follow-up survey of new users (1983) 37 responses; PARTICIPATE (on the Source)-sample of 100 new users (1983-l 984); INTMAIL-follow-up at four months of internal corporate users of a commercial mail system, 80 responses from managerial users; PLANET-percentages and means computed from raw data reported in [30, p. 1821, 115 scientific and professional USWS.
Note on use categories: Cumulative time on line at end of four months was arranged into four categories-less than 4 hours, 5-19 hours, 20-49 hours, and 50 or more hours. The modal category and percentage in that category are shown as a rough guide to the typical activity level of respondents. ‘The mean is determined by responses from 1 for “always” to 5 for “never.”
ual text items they receive or compose) down to about five [18]. Three years later, a sample of 273,000 usage hours continues to support this conclusion. The current average number of transactions handled per session on EIES is four; we cannot, however, accurately measure the delivery of text items virtually addressed by other text items, which would add to this total. As Rouse has pointed out [22], the human-factors literature supports the view that human performance deteriorates when the work load is too great or too small. There is therefore an optimal loading rate for phenomena such as communications. This is how we interpret the sign-on rate as a function of the number of transactions. The observation that intermediate users seem to suffer the most from information overload is consistent with some experiments that have been done on management information systems [3]. Individuals in decision-making situations seem to do just as well using summary data as raw data, but their confidence in the results is not as high. We suspect that intermediate CMCS users feel compelled to observe all the communications they can access in order to maintain confidence that nothing relevant is being overlooked. More experienced users are confident enough to use keywords and other filtering mechanisms. They develop more trust in the summary mechanisms associated with filtering. INFORMATION UNANTICIPATED
OVERLOAD VERSUS SYNERGY
The popularity of garage sales and flea markets demonstrates how one person’s junk can be another’s collect]uly 1985 Volume 28 Number 7
ibles. This is also true with information and ideas. For this reason, we believe that no automated routine can simultaneously filter out all useless and irrelevant communications for addressees, and at the same time assure their receipt of all communications that may be of value to them. This is especially true since what may be irrelevant when it arrives can become valuable once a user’s tasks or interests change. EIES users seem to recognize that communications on unexpected topics and from unexpected sources may increase their effectiveness, even as they decrease immediate efficiency. Some of the completely open public conferences do indeed seem a bit like intellectual flea markets. But like flea markets, they are well attended and of interest to their participants. One of Denning’s suggestions for filtering communications was to impose an organizational hierarchy on sending privileges: “Access among mailboxes can be restricted to persons authorized by an organization’s normal communications paths. Users cannot send to arbitrary mailboxes” [2]. Although it is true that the imposition of such a hierarchy would reduce message traffic in the short run, it is also likely to make the transmission of new information, “bad news,” or other kinds of organizational intelligence unlikely. Wilensky notes that In reporting at every level, a hierarchy is conducive to concealmentand misrepresentation.Subordinatesare askedto transmit information that can be used to evaluate their performance.Their motive for “making it look good” is obvious In addition. . . middle-level managers,and even lower level employees,sometimeshave a near monopoly on insight into feasiblealternatives. . . Whatever the shapeof
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the hierarchy, to extract information from those who have it typically requires bypassing conventional ranking systems.
[311
The problem of balancing the value of open communication channels with the cost of information overload is expressed by users when they name the least and most valuable aspects of communicating on the EIES system. The feature cited as “most useless or distracting” was annoyance with members who sent “junk messages” or made “off-the-wall comments” or “cute remarks,” rather than problems with any software features. In describing the most valuable feature of the system, users frequently cited the flexibility it allowed them; one user, for instance, refers to the “self-organization” of information. Among the most frequently reported productivity-related impacts are that EIES has increased the “siock of ideas” that might be useful in future work (this was reported by 71 percent of all users and 90 percent of users with 100 or more hours on line); and provided “leads, references, and other information useful in my work” (79 percent of all users, 95 percent of heavy users). The strongest predictor of these productivity-related benefits is how many new people a user as “met” on line and begun to communicate with [6]. To restrict communications to preauthorized partners would cut off the most valuable of the perceived benefits of system use. STRUCTURES AND PROCESSES FOR MINIMLZING OVERLOAD
Although restricting CMCS communications to certain channels goes against our strategy, there are some specific situations where it may be useful. In his study of communication and organizational control, for instance, Hage [Li] identifies two basic alternative mechanisms: “programming with sanctions” and “high feedback with socialization.” For centralized organizations with personnel performing routine (programmed) tasks, efficiency might be increased by restricting information to official channels. Conversely, for professionals performing complex, diverse, and nonroutine tasks, high feedback with much horizontal and out-of-hierarchy communication may produce the best results. In general, though, such restrictions are not advised.
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The basic problem is the whole “mailbox” analogy, in which control resides with the sender. With message groups and conference structures, where membership is self-selected by topic or interest and recipients can screen incoming communications, we believe individuals should be allowed to discover and implement the devices that work best for them, and to change them as needs and the volume of communications change. Users vary a great deal in terms of their previous experience with interactive computer systems, their level of CMCS use, their cumulative experience with a particular system, and the number of partners and topics they are involved with. This is why we believe there can be no single design that will optimize the trade-offs between useful information from unanticipated sources and information overload. For example, EIES users can set options for automatic delivery of waiting messages,for delivery on request, or for delivery of complete items for certain conferences and headers (e.g., author, keywords, and date entered) for others. A default option would be appropriate for new users, of course, since they would be unable to make intelligent choices about options before they had gained some experience with a system. The secret of designing on-line communication systems is sticking with process options-nothing should be content dependent. Designers should not try to impose specific organization structures, but should give individuals options for filtering out material. Users will use process options to control content as they see fit. Within the context of a single organization using a CMCS, there are process options that are not appropriate to a public system like EIES, which has members from scores of different organizations. One example is the incorporation of user roles or multiple subidentities that would correspond to organizational functions. An individual in an organization may be a worker on one project, a manager on another, a coordinator on a third, etc. This individual may have to deal with both personal matters and group matters. Within a single organization, it might be appropriate to identify a number of common organizational roles and to ask message senders to address their messagesaccordingly. This would self-organize incoming message traffic. The concept of using roles as a sending category index is ac-
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tually a psychologically appropriate approach in that it is easier for users to adapt to than some of the standard database approaches. Software design based on the systematic analysis of the behavior and practices of experienced users as they organize and filter their communications to prevent overload is more likely to be useful than design based only on casual observation and intuition. There is a high degree of unpredictability in determining which communications might interest a user. Interests may also be strongly time dependent or change with fluctuating situations in a group or an organization. As users become familiar with computercommunication technology, they begin, at a group level, to evolve their own norms for communication behavior. There are precedents for this process: As children we go through a learning process for using the telephone and for understanding the norms of behavior that have evolved for telephone conversations. These norms do not, however, prevent us from getting a certain number of nuisance calls. When we get a number of such calls from the same person, we tell that person to stop phoning us or we refuse to talk to them if they persist. Directed junk communications are a human problem more than they are a computer problem, the side effect of an on-line social system, rather than of any particular computer system. Huber [12] distinguishes two basic processes for increasing the organizational efficiency of information systems: message routing and message summarizing. Message routing need not be determined by the sender. Software can sort communications into categories based on conference structures and interest groups with selfselected memberships, for instance, or can permit recipients to route or filter them by topic. Message summarizing, or condensation, can be accomplished by structuring the form of inputs. Senders might, for instance, be required to adhere to length limitations, or to use votes or other numeric estimates instead of full messages. Summarizing can also be performed by human “digesters’‘-some bulletin-board operators, for instance, read incoming items, discard irrelevant ones, and summarize others before posting them on a bulletin board. We can also add a third to Huber’s two efficiency-increasing processes-social organization and social pressure can be used to regulate communication and make it more efficient.
Routing Information via a Conference Structure By a computerized-conferencing system, we mean software that supports on-line group interaction and task completion. The communications being generated and exchanged may include data and graphics as well as text. All of the conferencing systems we know of use the computer to keep a marker for each individual member, so that attention can be called to new items each time a particular member rejoins the conference. In a message system, communications from all sources and on all topics tend to get mixed together. By routing communications into topic-oriented discussion
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spaces, we make a quantum leap in screening capabilities and facilitate the emergence of on-line social groups with strong norms. There is a problem with finding appropriate terminology and metaphors for describing this concept in general terms, rather than as a package of specific implementations. Stevens [24] uses the term “many-tomany communication,” while the American Productivity Center has suggested “computer networking.” However, the former term does not make it clear that the process is computer based, and the latter might be interpreted as communication between computers rather than among groups of people using computers. A conference is simply a topic-oriented discussion or information-exchange space. Individuals can belong to as many conferences on as many different subjects or tasks as they wish. All communications on a specific task or subject are collected together in a space that can be accessed by members at any time. For instance, automatic routines can be set to pick up the full text of all new items for a conference of high interest, while selecting only “headlines” from new items in other conferences. Conference structures are unlike the “distribution lists” employed by many electronic mail systems in that it is the receiver, rather than the sender, who decides when and if to receive communications on a given topic. Often, special software routines for voting structures and other options are operative within a conference; such structures usually require a human moderator with the authority to add or remove members and add or change keywords. Conferences usually also have a member-status list showing conference membership, who has read what, and who is on line at any given time. Though conference software is most often operative on a single central computer, some systems, such as IBM’s internal EQUAL system and the EIES2 system, now under development, are distributed among many constantly or frequently updated computers in a network. When conference structures exist, discussions assume shape, continuity, and social order. Social pressure is often exerted to encourage members to put everything except urgent or personal communications into the structure so that members are not inundated with messages on subjects not of immediate interest. Members can also let each other know when entries seem completely “off the subject.” When a conference system is coupled with a message system, the flow of unwanted messages is greatly reduced. Messages tend to be used more for transitory things and short announcements of one sort or another. Personal notebooks or files facilitate the conference process by allowing members to draft and polish items before distributing them to the group. An analog to a conferencing structure is created by some receiving nodes in distributed message systems when they filter out messages addressed to a message list and place them on separate bulletin boards or in separate files (by the name of the distribution list), rather than in any individual’s private message queue. As more communication options become available,
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problems with junk mail and overload begin to decrease. Indeed, overload becomes no more than a transitory learning problem in a “rich” system environment. The key, as we see it, is that strategies allowing users to structure communications are intrinsically better suited to alleviating these problems than strategies based on nonautomated communication systems. This freedom does have its price, however, since users will need to learn some complex system features beyond simple sending and receiving operations. Filtering and Scanning Features David Morris, one of the principal designers of EQUAL, an IBM internal conferencing system, asserts that “An effective method of presenting each user with an overview of what is available and letting them pick what is of interest to pursue further is the single most important capability a CMCS can provide” (personal communication). Within a conference structure for a small group discussing a narrowly defined topic or working on a task, filtering and selection devices other than the conference structure itself may actually be detrimental to the group’s ability to accomplish its goal. For a large group, a complex task, or a broad conference topic, however, soml-3additional mechanisms for skimming and filtering may be necessary. Some systems allow users to scan limited portions of communications and then to decide which items and how much of each item to retrieve. For instance, EIES includes keywords for each item, and PARTICIPATE includes an “About” line in the header. EQUAL requires an abstract to be entered with each item and displays the abstracts when a user enters a conference, using the highlighting available on a full-screen terminal to call attention to new items. On the COM system, a user can set a “scan” command to print out only the first N lines of pending items. Users can then enter the command “read the rest” if they want to see the remainder of the entry, or “mark” the item for later reading [Zl]. One problem with this approach is that the writer will not know how many lines the reader will be scanning: The first two lines, for instance, might not summarize the subject sufficiently. If a scan command worked in a standard way for each recipient, by printing the first three lines, for instance, writers would learn to include a kind of abstract in that amount of space. They could also be prompted to provide a threeline abstract at the beginning of each item for particular conferences when a scanning convention has been adopted. Conferences can organize themselves if users specify keywords and associations to other items. A reader can then use search and retrieval functions to ask for items with a particular key, or a series of items associated with one another as a kind of subtopic or discussion thread in a conference structure. Automatic indexing routines can then be used on this information to produce conference outlines. An individual sitting at a meeting cannot extract all the statements dealing with a particular topic or relating to a comment made earlier in the meeting, but must listen to everything in order to
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hear the relevant information. Within a conference structure, though, information can be organized in such unique and convenient ways. AS software and user bkhavior can be used in combination to filter communications by topic, filters can also be imposed on individuals in a conference structure. Members whose contributions are not desired for one reason or another can be restricted to a “read only” status, or even excluded from the group. Similarly, if a particular sender is responsible for an inordinate number of useless communications, future messages from that sender can be screened out by receivers, with or without notification to the sender. On one conferencing system, there were problems with anonymous messages of an unpleasant nature for some of the female members. Software was implemented so that a recipient could block anonymous messages without blocking signed messages. The real issue with such options is social etiquette. Messages like “Sorry, you do not have the privilege of sending messages to (name)” might come into vogue. Length Limitations The permitted length of individual items can be limited in order to ensure that communications are concise. Different lengths may be suitable for different functions and different groups. In EIES, for instance, it was initially decided to limit individual messages and conference entries to 57 lines (although items in reports or personal hotebooks could be up to 400 lines long). On the EMISARI crisis-management system, items were limited to 9 lines [x’]. This prevents some of the more bureaucratic users from using messages as internal memos. Although a few individuals initially protested loudly, the complaints began to disappear as the volume on the system began to increase. Length limitations on EIES were set by a group of about 75 legislative science advisers and their resources persons, who created a TOPICS system to limit the length of inquiry items that could be broadcast to the entire group to only three lines [14]. The group discussed and agreed on this limitation before the software was implemented. Recipients had to actively “select” an inquiry in order to access the often voluminous material associated with it. It is important that groups new to this technology be encouraged to discuss the norms they wish to adopt. It is also quite common for such norms to change as a result of experience and later discussion. The presence of a leader or group member with experience in the technology can be helpful for pointing out the need for discussions as problems like overload arise. Users can circumvent length limitations by stringing several short items that are really only one long item together. Despite this loophole, however, limitations do exert pressure on users to keep communications within the limit; social pressure helps to reinforce this subtle guidance. There are various options for allowing users to create short items that reference longer items. For instance, it is possible to virtually reference text in such a way that
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the computer can check whether the item in question has already been seen by the reader: if so, the computer will not print it out, but will inform the reader that the particular item has been referenced. A given message will thus have different lengths for different receivers, depending on whether they have already seen parts of it or not. Other devices, such as process keys (SUMMARY, DETAIL, ELABORATION, etc.) can also be used to determine which part of a particular item a particular user sees. Delphi and Other Voting Structures
A larger number of users can exchange information in a more concise and precise way when numerical responses are used in place of conventional text responses. The computer can be used to average, analyze, and display results for a given issue. The PARTICIPATE system refers to this capability as dialogue balloting, which is explained as “polling not to elect or to sample but to facilitate participation” [24]. Such procedures can take the form of scales that indicate, for instance, the degree of agreement on a statement or proposal on a one-to-five or a one-to-ten scale, numerical estimates of items such as the proportion of a budget to be devoted to research and development or advertising, or the rank ordering of alternatives. With the Delphi technique, communication structures are designed to allow knowledgeable individuals to efficiently pool or compare information on complex problems [16]. The technique is traditionally implemented with pen and paper over several rounds. Analysis and feedback are provided to the respondents between rounds, allowing them to expand and/or change their original views. EIES provides some nine different Delphi-like voting scales that can be attached to conference comments. For example, an individual proposing a project modification can attach voting scales for “desirability” and “feasibility.” The computer would then collect the votes and provide a display of the resulting distribution. This is a highly efficient way of discovering if the group already agrees with a proposal and avoiding what may be a lot of unnecessary communication. Considering a series of items in this manner allows a group to make a quick determination of the issues on which they need to focus discussion. There are literally hundreds of potential communication structures in the Delphi literature; many of these lend themselves to implementation in a computerizedconferencing environment. For example, for controversial proposals a structure can be implemented to collect pro and con arguments, organize them according to matching counterarguments, and then solicit evaluation votes from the group as the arguments are presented. The merger of Delphi concepts and computerized conferencing can greatly minimize the amount of communication necessary for groups carrying out various planning functions. In fact, it provides a kind of group-oriented decision support system. A system was developed for a standards group on EIES to allow individuals to propose an alternative definition (standard) for a phrase. The system then col-
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lected votes on any such proposed revision. A proposed standard would be issued only if the agreement was unanimous. This rather simple software modification speeded up the group’s work considerably by keeping members up-to-date on the relative acceptance of all the proposed alternatives. As in any Delphi-like voting process, voters could change their votes at any time. The voting process and the associated structures for relating complex information devised in Delphi designs represent a highly condensed form of human communication allowing extremely efficient transmission of a great deal of information. It is the merger of these techniques into CMCS structures that will allow geographically dispersed groups to work as teams dealing with complex problems on a day-to-day basis. Leaders or Moderators
When activity is routed into topic-oriented conferences, software support can be provided for leadership or information-management functions. For instance, conference leaders are called “coordinators” on COM and “moderators” on EIES. Our controlled experiments with problem-solving discussions have demonstrated that a designated human leader for a computerized conference can help a group to accomplish its task [7]. Software support may empower a leader or moderator to edit items or keywords for clarity, or to delete or move inappropriate or out-of-date items. More importantly, a specified leadership role usually entitles an individual to make organizing suggestions that can help to limit irrelevant communications. Some bulletin boards also have moderators or “sysops” who play an active role in filtering and managing information. Among the ARPANET boards, for example, INFO IBMPC and AILIST are organized by moderators. Pen Names and Anonymity
We have mentioned the role that social pressure by group members can play in enforcing the use of conventions like conference structures and length limitations. Sometimes such norms are stated and stressed by the leader or manager of an on-line group. Often, though, group members collectively sanction an errant member. This can be done, of course, with signed messagesor conference comments, but only at the cost of considerable strain on the social fabric of the group. If pen names are used or anonymity is maintained, individuals can vote to sanction or criticize errant members without embarrassing themselves. For example, one EIES entry entered anonymously read, “Joe, please remember that 57 lines is a maximum, not a minimum.” A second chimed in with an anonymous “Amen.” Subsequently, “Joe’s” entries became noticeably shorter. Other Features for Minimizing
Overload
There are other computer-mediated communicationshandling techniques that have no direct counterparts in nonelectronic media: Messages and documents can be sent with a “self-destruct” date, or a sys-
Purges and Discouraged Sending.
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tern default c.an be set to automatically purge old items. For instance, the ONTYME messagesystem purges undelivered items after about four weeks. Although these procedures may indeed protect receivers from “out-ofdate” communications, they unfortunately also prevent users who may have been unable to sign on for one reason or another from receiving items that might still be of interest. A more adaptive feature incorporated into some systems (e.g., COM) informs would-be senders when intended recipients have been off line for a significant interval. EIES includes a convention that notifies members when an intended recipient is to be away for a certain length of time. Features that allow system users to communicate with themselves can be useful for remembering and organizing information. For instance, EIES has a personal “reminder file” that stacks references to unanswered messagesor other items. lndividuals can remind themselves with “alarms” that send them messagesat prespecified times. These features, sometimes called “tickler files,” can be very helpful on busy systems.
Alarms and Reminders.
Notifications. On EIES an individual can edit a message or conference comment. All receivers who had already read the original would then be sent a notification that the item had been modified. The receiver could then decide whether or not to retrieve the new version. Notifications can also be sent to writers of private messagesto alert them when receipt occurs. This allows a sender to pace additional communications to a particular receiver. In a conference, notification is also available, on demand, of a conferee status list indicating what different members have and have not read. These signals are very important for allowing individuals to regulate the flow of traffic in a meaningful manner. Costs. For an organization having problems with electronic junk mail, the ultimate remedy might be the imposition of (chargeson a per-transaction basis. If senders are charged according to the number of recipients, the number of messagessent to many individuals is bound to drop. This approach is not recommended unless other techniques have failed. A more sophisticated approach is to charge senders according to both the size of the message and the salary of the recipient [28, 291. CONCLUSION: SUPERCONNECTIVITY AND THE ELECTROPOLIS
The most funclamental impact of a CMCS is to increase the social connectivity of users (i.e., the number of people in regular communication) by about tenfold. We use the term superconnectivity to capture the essence of this order-of-magnitude change. Joining the “electropolis” of an active CMCS can be stressful in the short term, but should also significantly increase opportunities for fruitful interaction. It is very difficult for individuals to adapt to such a
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new communications paradigm. It is far easier to think of computer-mediated communication in terms of preexisting systems, like the telephone or the postal system. It is also easier to market such systems as cheaper but equivalent alternatives to conventional communications structures. People are not easily sold on anything that promises change in cognitive processes and organizational social structure. The majority of the activity to date with CMCS’s has therefore been in simple “electronic mail” and “message” systems. Furthermore, it is difficult to take the significant long-term impacts of CMCS’s into account in the justification and planning process. Fortunately, professionals in the field do realize that the automation of conventional manual systems has often been the wrong way to go, historically, and that, although such efforts can sometimes boost efficiency, they can rarely boost effectiveness. In the computer-mediated environment, overload is as much an important motivational factor for encouraging users to develop systems skills as it is a problem. Different individuals are overloaded at different levels as a function of how much information they can perceive and deal with cognitively. The real problem is understanding the group and organizational objectives and providing the tools that allow individuals and groups to structure their own communications. Any process that limits overload by structuring content will also destroy many potential benefits. Tools for limiting overload should be based on structuring processes and should allow individuals to control content. With a variety of software tools for managing communication and information, users can not only adapt to high levels of information input, but can actually thrive. For instance, Tapscott observed the following in his study of pilot users of a rich system: It was hypothesizedthat the disparity between perceived “information needed”and perceived “information received,” noted at the time of the pretest,would decreasefor the pilot group. This did not occur. There were a number of improvementsbetween the pretest and posttestin the “information received.” However, the perceived findings suggestthat as accessto information improved, so did expectationsregarding what is possibleand perceived requirements regarding what is necessary.[x] In any organization there are formal and informal communications. In a sense this is analogous to the “structured” and “unstructured” dichotomy in decision support systems. Computer-mediated communication systems allow informal communication that is semistructured and highly adaptive in nature. By increasing the number of individuals who can be involved in informal information flows, we offer them more of an opportunity to pool their talents and expertise, and facilitate the lateral movement of information in organizations. Productivity-increasing concepts like matrix management (i.e., the assignment of personnel resources to task teams on a project-by-project basis) and lateral task groups become more feasible. To miss these
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opportunities by trying to impose the formal hierarchical communication rules that are traditional for internal memorandums would be the height of folly. Overload, within the context of an organization, is essentially a behavioral phenomenon. It makes more sense to address inappropriate behavior through social norms and sanctions than to obscure the problem with software. It is very easy on many message systems to accept a message, look at its title, and then delete it. This action would not be reported back to the sender, who would assume that the message was received and read. In a formal structure, this is clearly a conscious risk decision for the receiver. In an informal one, it is a more serious violation of the cooperative relationship between sender and receiver, comparable to not returning telephone calls. If CMCS’s are to accommodate and expand the informal exchange process in organizations, junk mail will have to be dealt with by social sanctions, since attempts to deal with junk mail and other negative aspects of information overload entirely by technological means or by the imposition of a formal hierarchical structure would compromise the utility of the system for improving informal communication exchange. Acknowledgments. We are grateful to all of the staff and associates of the Computerized Conferencing and Communications Center at NJIT for their participation in the research projects whose results are described in this paper. Jacob Palme facilitated access to COM and surveys of its users, Harry Stevens and Christine Bullen assisted with access to PART1 users, and David Morris provided access to IBM’s EQUAL and its documentation. Elaine Kerr collaborated in the surveys. Elizabeth Rumics and the reference staff at the Upsala Library assisted with obtaining many of the publications cited. We would also like to thank Ray Panko, Rob Kling, and our anonymous ACM reviewers for their helpful comments. REFERENCES 1. Baum, A., Calesnick, L., Davis, G., and Gatchel, R. Individual differences in coping with crowding: Stimulus screening and social overload. /. Pers. Sot. Psychol. 43,4 (Oct. 1982). 821-830. 2. Denning. P. Electronic junk. Commun. ACM 25, 3 (Mar. 1982), 163-
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Hiltz, S.R., and Turoff. M. Office augmentation systems: The case for evolutionary design. In Proceedings of fhe 15th Hawaii International Conference 011System Sciences, Vol. 1 (Honolulu. Hawaii, Jan.). Univ. of Hawaii, 1982. pp. 737-749. Hiltz. S.R.. Turoff, M.. and Johnson. K. Mode of communication and the risky shift: A controlled experiment with computerized conferencing and anonymity in a large corporation. Res. Rep. 21, Computerized Conferencing and Communications Center, New Jersey Institute of Technology, Newark, 1985. Huber. G. Organizational information systems: Determinants of their performance and behavior. Manage. Sci. 28, 2 (Feb. 1982), 138-153. Johansen. R.. Vallee, J.. and Spangler. K. Elecfronic Meetings: Technological Alternatives and Social Choices. Addison-Wesley, Reading, Mass., 1979. Johnson-Lenz. P.. and Johnson-Lenz. T. The evolution of a tailored communications structure: The topics system. Res. Rep. 14. Computerized Conferencing and Communications Center, New Jersey Institute of Technology, Newark, 1981. Kerr, E.B.. and Hiltz. S.R. Computer-Mediated Communication Systems: Sfatus and Evaluation. Academic Press, New York, 1982. Linstone. H.. and Turoff. M. The Delphi Method: Techniques and Application. Addison-Wesley, Reading, Mass.. 1975. Mehrabian. A. A questionnaire measure of individual differences in stimulus screening and associated differences in arousal. Environ. Psychol. Nowerbal Behav. 1. 2 (Spring 1977), 89-103. Miller, G.A. The magic number seven plus or minus two: Some limits on our capacity for processing information. Psychol. Rev. 63, 2 (Mar. 1956). 81-97. Miller, CA. Information input overload. In Proceedings of the Conference otz Self-Organizing Sysfems, M.C. Yovits. G.T. Jacobi. and G.D. Goldstein, Eds. Spartan Books, Washington, 1962. Palme. J. You have 134 unread mail! Do you want to read them now? In Computer-Based Message Semites, H.T. Smith, Ed. IFIP Proceedings, Elsevier North-Holland, New York, 1984, pp. 175-184. Palme, J., and Albertson. E. COM-teleconferencing system-Advanced manual. C10157E. Stockholm University Computing Center, Sweden, 1983. Rouse, W.B. Design of man-computer interfaces for on-line interactive systems. Proc. IEEE 63, 6 (June 1975). 1347-857. Sheridan, T.B.. and Ferrell. W.R. Mm-Machine System: Information, Control, and Decision Models ofHumans Performance. MIT Press, Cambridge, Mass.. 1974. Stevens, C.H. Many-to-many communication. CISR 72. Center for Information Systems Research, MIT, Cambridge, Mass., 1981. Tapscott. D. Research on the impact of office information communication systems. In Compufer Message Sysfems, R.P. Uhlig, Ed. NorthHolland, Amsterdam, 1981. pp. 395-409. Tsichritzis. D., Rabitti, F.A.. Gibbs, S., Nierstasz. 0.. and Hogg, J. A system for managing structured messages. IEEE Trans. Commute. COM-30, 1 (Jan. 1982). 66-73. Turoff, M. Party-line and discussion: Computerized conferencing systems. In Proceedings of the Isf International Conference on Computer Contmurlicafims (Washington, D.C.. Oct. 24-26). ACM, New York. 1972. pp. 161-171. Turoff. M. Information and value: The internal information marketplace. Techml. Forecasfing Sot. Chmge. To be published. Turoff. M.. and Chinai, J.S. The design of an information marketplace. Computer Nefworks. To be published. Vallee. J., Johansen. R., Randolph, R., and Hastings, A. Group Cow murlicatim through Computers. Vol. 4. Social, Mamgerial, and Economic Issues. Institute for the Future. Menlo Park, Calif., 1978. Wilensky. H.L. Organizational Irtfelligeoce: KmwIedge md Policy in Government md Indusfry. Basic Books, New York, 1967.
CR Categories and Subject Descriptors: H.4.3 [Information Systems]: Communication Applications; K.4.3 [Computers and Society]: Organizational Impacts General Terms: Design, Human Factors Additional Key Words and Phrases: computerized conferencing. filters, information overload Authors’ Present Address: Starr Roxanne Hiltz and Murray Turoff, Computerized Conferencing and Communications Center, New Jersey Institute of Technology, Newark, NJ 07102. Permission to copy without fee all or part of this material is granted provided that the copies are not made or distributed for direct commercial advantage. the ACM copyright notice and the title of the publication and its date appear. and notice is given that copying is by permission of the Association for Computing Machinery. To copy otherwise, or to republish. requires a fee and/or specific permission.
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