Human-Computer Interaction 3e Dix, Finlay, Abowd, Beale

exercises  -  14. communication and collaboration models


In Section 14.3.2, we discussed the highly contextual nature of the spoken word, including the use of deictic reference and indexicals, and the (officially) ungrammatical and fragmentary use of sentences. Try listening to social chat over cups of tea - collect examples of different forms of contextual utterance.


There are often objects of shared attention during social chat, perhaps a notice board, or magazines on a coffee table. These will be one obvious source of context. When students record statements such as 'I like that', they should also record whether the indexical refers to a previous utterance or to something external. They should try to observe exactly how external references are made: for example, whether people point to a notice, refer implicitly to the article someone else is reading or use the direction of their own gaze.

In a small group, students should listen particularly carefully for the use of the pronoun 'you'. Does it refer to the whole group (excluding the speaker), or to a particular person. If the latter, then how is it made explicit - eye gaze, body position? Other pronouns like 'we' or 'she' can be equally contextual.

Students should also look out for implicit context, for example 'a longer tail would improve the aerodynamics', spoken when the listener is looking at a picture of a kite. Although the sentence has no pronoun there is an implicit subject 'of the kite you're looking at'. This form of contextual statement can become arbitrarily obscure, for example as one person meets another: 'it's in your pigeon hole' - referring to an overdue report. As students become more adept they can listen more carefully, looking for the shift in conversational focus, and breakdowns where the context is not successfully negotiated.



Go into an office or other place where several people are working together. Try to note down in as much detail as possible what they are doing and when. Do this with different foci: focus on the direct interpersonal communications, focus on the shared objects such as a calendar or document, or focus on one worker at a time. Whilst collecting data and when ordering your notes, look for breakdowns and misunderstandings, and for implicit communication through objects. Look also at a particular task over a period of time, and note the number of interruptions as a worker performs the task, or the way a single task is contributed to by several workers.


This exercise is similar to Exercise 15.5. However, whereas the task analysis in 15.5 is quite structured, this exercise is not intended to produce the same form of precise task sequences, etc. The intention is to expose students to the vast range of social situations within a typical work environment. Recording techniques such as those described in Chapter 9 might well be used.

In particular, this exercise is a good chance to introduce the use of video or audio recording equipment if it is available. Students will soon learn how difficult it is to position a microphone so that it picks up more than one worker and so that recordings are not dominated by the sound of a typist. Similarly, they can gain first-hand experience of the problems of static camera positioning. If you are lucky, you may have access to multiple cameras and split-screen recording equipment.

Although such equipment can be useful, its lack is not a disaster. Many ethnographic studies use only a pencil and paper, with perhaps some audio recording. However, developing appropriate shorthand then becomes essential (see Suchman [334] for examples of appropriate notation).

Some forms of communication in the office can be quite subtle, perhaps 'overhearing' of conversations, or noticing when something is being written on a wall calendar. Developing an observant eye for such subtleties is largely a matter of practice.



What is speech act theory? Describe positive and negative issues that have arisen when it has been embodied in a specific system.

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Speech act theory characterizes utterances by what they do - their effects. These can include requests, promises, assertions, etc. Conversation can therefore be analysed as a series of speech acts and generic conversations can be generated. The theory is used in Coordinator. Benefits - structure of conversation made explicit, clarifies effects of utterances, some evidence that it has helped train communication skills. Problems - disliked by users, speech acts don't fully describe conversations and are therefore too restrictive, unnatural.



Compare turn-taking, round-robin and free-for-all as floor control mechanisms. When might each be effective?

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Answer should define each of these and their strengths and limitations. Discuss particular examples of groupware such as meeting rooms, shared editors, etc., and possible protocols for each - some are about communication, some about changing shared artefacts. Also discuss social protocols and how they can be integrated with more flexible formal protocols.


EXERCISE 14.5 [extra - not in book]

Is face-to-face communication a useful model for computer-mediated communication? Justify your position.

answer available for tutors only

Computer-mediated is poorer than face to face - tends to lose one or more of gestures, body language, eye contact, back channels. Attempts have been made to address this problem in CMC. For example, emoticons are symbols introduced into text based communication to indicate mood. They are needed because of the lack of back channels, facial expressions, tone of voice and gesture which indicate this in face to face communication. However these are only effective if participants share understanding of their meaning. Other ways of enhancing CMC are to include video and audio, which are richer than text but not still not as rich as face to face. After consideration of these issues the likely conclusion is that CMC is unlikely to match the complexity and richness of face to face, but that it may still be useful as a form to emulate


EXERCISE 14.6 [extra - not in book]

What are the benefits and limitations of using adjacency pairs as a model for the design of computer-mediated communication systems?

answer available for tutors only

A key advantage of using adjacency pairs as model is simplicity - straight forward turn taking - respond to one utterance with a paired utterance. A key problem is the restrictiveness. Actual conversation is more flexible than this suggests - CMC probably needs to be too.


EXERCISE 14.7 [extra - not in book]

What is distributed cognition? Why is it significant in understanding groupware?

answer available for tutors only

Thinking happens not just in the head but in the external relationships with things in the world and with other people. Distributed cognition highlights the Importance of mediating representations - the embodiment of understanding. Artefacts such as whiteboards become more than just record keeping devices - they become part of what is known. Also cooperation is less about transfer of knowledge but about creating new knowledge. Makes life easier for designer of groupware - don't have to consider internal processes - can concentrate on manifestations of shared knowledge.

Individual exercises

ex.14.1 (ans), ex.14.2 (ans), ex.14.3 (tut), ex.14.4 (tut), ex.14.5 (tut), ex.14.6 (tut), ex.14.7 (tut)

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