The Computer Science of Everyday Things
Contents
1. is optimal precisely because it has no other purpose than to be efficient However all Nokia functions have a shortcut code which as it is so named is presumably to provide a brief alternative Again the Huffman tree lends itself to an improved code moreover since Nokia do not use their shortcut codes efficiently we can provide both Nokia s original and a non overlapping code this gains the best of both worlds whatever the best of the Nokia world is supposed to be Nokia s shortcuts have an average access cost of 3 64 keystrokes the combined approach has an average cost of 2 87 keystrokes Such improvements can be made by applying purely routine computer science to user interface design The next section illustrates what we can do when more imagination is brought into play 5 2 More efficiency based on a novel design Full details of the example discussed in this section can be found in 12 Most keys on the Nokia have letters on them and just as they are used for entering names e g SMS messages they could be used for searching for functions Reference to any algorithms book will find numerous ways of making good use of keys for searching Here we explore hash codes Given a function name such as Call Waiting we find its hash code by using the Nokia s stan dard keypad Thus the first two letters of Call Waiting C and A are on the key and the third and fourth letters are on 5 thus the h2. routinely design computer pro grams to be efficient and correct We need to see the user as at least as important as a computer and the user interface as a program for the user User interface design then becomes a matter of programming the user Many problems in user 4Two examples uniformly from function to function the key behaves differently unnecessarily in different functions In Phone book while entering a number deletes digits whereas in Clock again while entering a number goes up a level in the menu hierarchy In Clock then it is not possible to correct numbers all digits have to be entered correctly first time short cut codes are not displayed interface problems then come down to failing to provide the user with a correct and efficient inter face That the user interface also needs to be com putable is obvious but this is an idea that seems to be ignored in almost all interfaces Even such simple tasks as determining a sequence of moving a cursor from one screen position to another in Microsoft Word are undecidable 24 Once user interfaces are seen in this light then many ideas from computer science can be applied This paper showed how familiar algorithms can be applied to user interfaces elsewhere we have ex plored applying ideas like declarative programming to user interfaces 25 Given that many user interface problems can be attributed to bad computer science much of conventional empi
3. their usability is often low Usability problems are not just irritat ing but are costly and stressful and hazardous in many contexts whether the users concerned are airline pilots office workers using photocopiers or home users struggling with video recorders It is popular to argue that everyday things are harder to use than they need be and that improve ments must be sought in human factors that is in the study of users and their tasks 16 and in the study of ecologies and context of use 15 etc The Proceedings of the Australasian User Interface Conference Bond University Gold Coast Aus tralia January 29 February 1 2001 lack of user centred design is the conventional reason for the failure of almost all programmed systems 10 Indeed as industry can evidently sell to con sumers without improving usability business prac tice itself creates a source of usability problems that is again of non technical origin Usability then as a field has become dominated by marketing social empirical and statistical methods alien to computer scientists The broad emphasis on human factors encourages computer scientists further to dismiss usability as irrelevant to their focus Indeed in simple terms computer science appears remarkably successful cf Moore s Law 2 below superficially confirming that usability problems must be solved elsewhere But successful interaction clearly requires un derstanding
4. to be asserted A computer scientist would wonder why the al phabetic labels are not more sensibly organised Of the 12 available keys only 9 are used and the allo cation of letters to keys does not reflect frequency of use There are international standards of letter allocation but as phones differ they cannot be an important consideration and the silliness of the international standards merely begs the question why the standards bodies do not ask computer sci ence questions either 5 3 Other benefits Both examples above rely on a specification of the Nokia device Once the device is specified it is easy to devise and analyse many improvements The inconsistencies in the actual user interface of the Nokia suggest that Nokia do not use a pro fessional computer science approach to user inter face implementation That is given a more or less formal approach inconsistencies are hard to implement whereas in an informal approach incon sistencies are easy if not an expected consequence It is arguable that consistency makes devices eas ier to use outside of games certainly consistency makes user manuals easier to write and shorter In fact user manuals can be generated at least in part automatically 30 then not only can user manuals be used concurrently early in the design process but they can have guarantees if desired that they are complete and correct 6 Programming the user interface Computer scientists
5. to come on in interesting patterns this is presumably a test mode or perhaps a salesroom eye catching feature but the manual does not de scribe it The JVC HRD580 EK video recorder has the opposite problem 21 It has features that cannot be used with the user manual The manual has textual descriptions of complex operations such as tuning in the VCR to UHF channels Reading these sections is time consuming yet the corre sponding features on the VCR have short time outs So by reading the manual while trying to per form the operations described ensures the VCR will time out then the user will be reading the wrong part of the manual to explain what the VCR is doing What the user is reading becomes counter productive One solution to the system manual synchronisation problem is for the device itself to present instructions to the user since it knows what state it is in it can always present the appro priate sections of the manual 1 There is not space here to analyse these assorted criticisms further Each unusable system is unus able in its own way the faults are too varied to easily bring into clear comparison See 26 for a systematic analysis of a long list of usability prob lems with a single product One reason why faults persist is that nobody has conceptual leverage on the problems manufacturers employ production processes that result in incoherent usability issues nobody understands the results
6. 5 Computer science applied We need conceptual leverage not on problems in teresting as they may be but on solutions User interfaces might be improved by better computer science but can improvements be achieved system atically In this section we outline a computer science appraisal of the Nokia 5110 mobile phone s user interface We provide evidence that applying elementary computer science will improve user in terfaces 5 1 More efficiency based on Nokia s design Full details of the example discussed in this section can be found in 28 The Nokia 5110 handset organises most of its functions in a tree which is presented to the user as a menu Clearly the design assumption is the user will search the tree to find functions to activate Computer scientists are familiar with search and indeed with search trees A Huffman tree is the most efficient way to organise a search tree given that there is a fixed set of keys 28 We could simply determine the aver age cost per function and compare it with Nokia s design but the so called cost of knowledge graph itself introduced by psychologists to evaluate user interfaces shows increasing efficiency the longer it is used for the Huffman over Nokia s original design after 500 key presses a user of the Huffman design is twice as efficient It can be pointed out that Nokia s design may have virtues other than trying to minimise keystrokes certainly a Huffman tree
7. In teraction Volume IV pages 58 86 Ablex 1993
8. The Computer Science of Everyday Things Harold Thimbleby Computing Science Middlesex University Bounds Green Road London N11 2NQ http www cs mdx ac uk harold Abstract Technology is fashionable wonderful and getting better Moore s Law predicts substantial sustained improvement Yet the usability of everyday things is low video recorders being a notorious example It seems to follow that improvements must be sought in areas outside technology such as human factors But a premise is wrong in fact the technology the embedded computer science is appalling Obsolescence a symptom of Moore s Law hides flawed design poor products are replaced rather than fixed The poor quality of the computer science of everyday things is eclipsed by the hope for fixing today s problems with tomorrow s consumption This paper reviews Moore s Law and the usability of everyday things it shows that professional computer science can improve usability with ease Improvement will be essential when ethical and environmental issues become as they will unavoidable design criteria Keywords Moore s Law User interfaces Mobile phones Programming user interfaces Environment 1 Introduction Almost all modern everyday things from mo bile phones cameras central heating controllers calculators to wristwatches and airplanes work because of embedded computer programs While most are technically impressive
9. akes the memory equal the display if it already contains zero which it may not To make the memory zero you have to press twice but pressing it the first time sets the display to the memory which loses the number you wanted to store The solution is not easy and there is no solution that avoids the risk of calculator overflow If you need paper to work it out why not use the paper for the memory the differences or the curious features shared by both calculators Neither comes with user manuals or other information that warn of or reveal any problems Calculators are impressive especially if a prepared salesman shows you them going through some calculations It is possible to demonstrate the memory in action apparently working Only some critical thought would determine that it is a very peculiar feature 4 1 More examples A cynical reader might take the Casio calculators as specially selected but see 29 This section gives a brief selection of problems to illustrate the diversity of problems All should have been easily detectable and all are easily avoidable in principle See 9 18 20 for examples of usability problems with safety critical devices where there is an obli gation improve usability The Sony television KV M1421U has a remote control the RM 694 Not only are their colour number and layout of buttons different but the user interfaces are unrelated they work in com pletely different ways which is
10. and P Duguid The Social Life of Information Harvard Business School Press 2000 3 C M Christensen The Innovator s Dilemma When Technologies Cause Great Firms to Fail Harvard Business School Press 1997 4 Commission of the European Communities Proposal for a Directive of the European Parliament and of the Council on Waste Electrical and Electronic Equipment Volume COM 2000 347 provisional 2000 5 de Longhi Pinguino Electronic 578909 02 97 1997 eco 6 Ss 10 11 12 13 14 15 16 17 18 19 P Duquenoy and H Thimbleby Justice and design In M A Sasse and C Johnson editors IFIP Conference Interact 99 1999 C A R Hoare Communicating Sequential Processes Prentice Hall International Series in Computer Science 1985 M Jones G Marsden and H Thimbleby Empowering users with usability certificates In S Turner and P Turner editors BCS Conference HCI 2000 Volume II pages 37 38 2000 P B Ladkin Analysis of a technical descrip tion of the Airbus A320 braking system High Integrity Systems Volume 4 Number 1 pages 331 349 1995 T Landauer The Trouble with Computers MIT Press 1995 G Marsden P Duquenoy and H Thim bleby Ethics and consumer electronics In A D Atri A Marturano S Rogerson and T W Bynum editors Fourth International Conference on the Social and Ethical Impacts of Information and Communicati
11. ash code of Call Waiting starts 2255 As a user enters a hash code the new design displays in a scrolling list all functions that match the hash code To disambiguate the code the user can either use up and down arrows as in the conventional Nokia design or enter more digits If the user presses the key the last digit is deleted and the hash code looked up again and the display is refreshed Marsden built a simulation of the original Nokia and the new design and compared their use Both designs used the same screen image Of the experimental scenarios completed on the new design users achieved an average 9 54 3Due to bugs in Microsoft Word it turned out for unfathomable reasons to be impossible to place a graph in the original Word version of this paper to illustrate this point Again this is a computer science problem bad programming in a consumer software package This published version was formatted using TFX key presses in comparison to the Nokia design where 16 52 key presses were required This was a strongly significant result p lt 0 001 with users requiring approximately 7 fewer key presses on average to access the functions on the hash code design The overall mean times not key press counts for the hash code phone was 33 42 seconds com pared to 42 02 seconds for the original The im provement though was not consistent enough from person to person for a statistically significant dif ference
12. bility benefits 4 Buggy everyday things There are many gadgets representing bad computer science but most are so bad that they are impossi ble to describe clearly Perhaps the best example because it is in principle straight forward pervasive yet inexcusably bad is the handheld calculator Hand held calculators are a mature technology Calculators have well defined requirements of ac curacy and performance and so on There have been many generations of calculator designs and the manufacturers have had many opportunities to step their production to fix problems The only limitation on calculator quality is manufacturer in clination Research into calculator user interfaces has a twenty year background 25 29 Casio is the leading manufacturer of hand held calculators Two of their basic models are the SL 300LC and the MC 100 which look very similar The SL 300LC is shown in Figure 2 e Pressing the 9 keys 100 17 5 e g to cal culate 17 5 tax on 100 on the SL 300LC gets 117 50 The MC 100 with exactly the same keystrokes gets 121 21212 Two similar looking confusable calculators made by the same manufacturer do different things Since the key is unpredictable from calculator to calculator and even in different contexts in the same calculator users soon avoid using it thereby Figure 2 The Casio SL 300LC Note the highly visible self advertising memory keys in the middle of the top row of button
13. for mation Technology Standards Butterworth Heinemann 1993 H Thimbleby The frustrations of a push button world In Encyclopedia Britannica Yearbook of Science and the Future pages 202 219 Encyclop dia Britannica Inc 1993 H Thimbleby Treat people like computers In A Edwards editor Extraordinary People and Human Computer Interaction pages 283 295 Cambridge University Press 1995 H Thimbleby A new calculator and why it is necessary Computer Journal Volume 38 Number 6 pages 418 433 1996 H Thimbleby Design for a fax Personal Technologies Volume 1 Number 2 pages 101 117 1997 H Thimbleby Visualising the potential of interactive systems In Tenth IEEE Inter national Conference on Image Analysis and Processing ICIAP 99 pages 670 677 1999 H Thimbleby Analysis and simulation of user interfaces In S McDonald Y Waern and G Cockton editors BCS Conference HCI 2000 Volume XIV pages 221 237 2000 H Thimbleby Calculators are needlessly bad International Journal of Human Computer Studies Volume 52 Number 6 pages 1031 1069 2000 H Thimbleby and P B Ladkin A proper explanation when you need one In M A R Kirby A J Dix and J E Finlay editors BCS Conference HCI 95 Volume X pages 107 118 1995 I H Witten and H Thimbleby User mod elling as machine identification New methods for HCI In H R Hartson and D Hix editors Advances in Human Computer
14. ho do not understand com puter science 6 Because of the market demand practising computer scientists even ones not working in user interfaces are trained to a low standard 7 Manufacturers put their best programmers onto tasks that must work correctly In a mobile phone say these will include battery management and radio communications Customers will notice quickly if the phone does not work at all but most customers will blame themselves when they find the user interface tricky Thus manufacturers put their worst programmers onto user interfaces 8 Computer scientists who develop a product are familiar with its user interface Their knowl edge and experience will make it and in gen eral all devices much easier for them to use Therefore computer scientists discount the ev idence of usability studies 9 Because it stimulates consumption users are encouraged to blame themselves rather than the products they buy Researchers too are consumers with similar stakes in the usability of the everyday things they own It is unusual and depressing to question the design of prod ucts you have chosen to buy especially if it brings into question the standards of your own profession 7 Sustainability and ethics With all the reasons against improving user inter faces where will improvement come from Moore s Law apparently underwrites manufac turers confidence in faster and more powerful pro cessors for their pr
15. ld not expect the law to apply to the USA and to Japan It is too coincidental 2 More likely then the law is an observation about capitalism rather than a surpris ingly uniform rate of technological breakthrough Stimulating consumer demand by enhancing performance expections is a very creative activity and requires insight into market behaviour Coincidentally most creative professionals are not technical the people employed by industry to enhance products do not understand or realise the limitations of the embedded computer science 4 User interfaces are complex and problems in usability rarely show up immediately By the time a user becomes dissatisfied with a product Moore s Law ensures new products are available There is little need for manufacturers to make old products better if by the time their limitations are discov ered users prefer a new product to a fixed older product Thus Moore s Law encourages loss in de sign quality manufacturers can assume customers prefer to upgrade to a faster or more featured prod uct In other words provided the product lasts long enough a few months it need have no long term usability features this makes it easier to design and to get away with poor quality design methods Even if a product fails completely con sumers would probably rather pay to upgrade than wait for it to be repaired Moore s Law encourages fatalistic computer sci ence Your current prog
16. obvious e g from their statecharts 27 One concludes either Sony never specified the user interface or did not worry about the gratuitous differences The Panasonic Genius microwave cooker has a clock The user interface allows the clock to be set to any number 0000 to 9999 Despite the impression that it may be a 24 hour clock it only runs when set to a valid 12 hour time Nothing gives any indication why the clock will not run when it is set to a time such as 2230 23 31 The Nokia 5110 mobile phone has a menu driven user interface providing access to all the phone s functions see 5 However some functions such as keypad lock are not in the menu structure Thus a user without the phone s manual may be unable to find such functions There is no reason why all functions should not be in the main menu The De Longhi Pinguino 5 air conditioner can not be used without the user manual There are delays between pressing buttons and things hap pening so a user might press a button twice to really do something but this resets the mode of the device before it has even started When the device is running its on light is off A front panel light labelled memo control is described in the manual as meaning that there is a three minute wait if it is flashing or that the air conditioner is in cooling mode if it is on continuously It is possible to press the buttons on the front panel to get all the lights
17. oducts Manufacturers can an ticipate adding features to systems without seri ously impacting their performance Equally they can anticipate users preferring to replace their cur rent products with new ones users prefer to replace rather than have inferior devices fixed By the time users find problems with user interfaces the market will have moved on and the users can be promised their problems will be fixed by new features The result of this is continual replacement In dustry benefits and consumers willingly become fashion followers Mobile phones for example are not sold on their effectiveness for communication but on their status value There is a serious consequence what happens to all the obsolete devices In the UK 900 000 tonnes of mostly toxic waste electronics is buried annually in land fill sites This is not sustainable Some notable efforts have been made to recycle for instance shipping computers to the third world but this is merely shifting the toxic waste from one back yard to another Manufactuers may be persuaded by legislation 4 to use more environmentally friendly materials and processes but this does not address the core problem The computer science of everyday things has been so bad for so long that we all take it for granted It is time to design user interfaces so they are robust so they can be upgraded These are conventional computer science issues There is not space to cover further e
18. of both humans and computers The computer science of everyday things has ignored usability we give examples below and its stan dards are woeful This factor of low usability is ignored not just by designers and usability workers but also by computer scientists There is a serious educational problem both at the level of educating technologists to program user interfaces better and at the level of encouraging consumers to demand higher standards of lifetime usability which could easily be provided 2 The impressive Moore s Law Technology is getting better and has increasing performance over time We can represent this by the graph see Figure 1 using a curve of posi tive slope it is not necessary to worry about the precise shape of the line or exactly what per formance is measuring For any particular task the user has some minimal level of performance p will be required From the graph it is clear that there is a crossover when the lines intersect at performance p and time t Before time t technology is delivering inadequate performance after t technology can deliver more than adequate performance Norman 17 crediting Christensen 3 makes the following argument Before the crossover time Performance Figure 1 Perfomance of technology increases with time curved graph After time t perfomance exceeds the crossover value p t manufacturers need only promise technical ca pability which i
19. on Technolo gies Ethicomp 99 1999 G Marsden H W Thimbleby M Jones and P Gillary Successful user interface de sign from efficient computer algorithms In ACM Conference CHI 2000 Extended Ab stracts pages 181 182 2000 G Moore Moore on Moore s Law Corporation Distinguished Lecture http www uvc com Nanometres and Gigabucks University Video 1996 R Nader Unsafe at Any Speed Pocket Books 1965 B A Nardi and V L O Day Information Ecologies Using Technology with Heart MIT Press 1999 D A Norman The Psychology of Everyday Things Basic Books 1988 D A Norman The Invisible Computer MIT Press 1998 E Palmer Oops it didn t arm a case study of two automation surprises In R S Jensen and L A Rakovan editors Eighth Inter national Symposium on Aviation Psychology pages 227 232 1995 B Reeves and C Nass The Media Equation Cambridge University Press 1996 20 21 22 23 24 25 26 27 28 29 30 31 N B Sarter and D D Woods How in the world did we ever get into that mode mode error and awareness in supervisory control Human Factors Volume 37 Number 1 pages 5 19 1995 H Thimbleby Can anyone work the video New Scientist Volume 129 Number 1757 pages 48 51 1991 H Thimbleby Computer literacy and usabil ity standards In C D Evans B L Meek and R S Walker editors User Needs in In
20. pensively travel on land at up to 1000km h though most transport is undertaken by lorries travelling around 110km h much less if we average over the journey rather than take maximum legal speeds lems they should learn how to use things properly Our society is certainly a complex place and people do need to be technology literate because that is how the world is But this practical response can be used as an excuse to make systems over complex because users will take it upon themselves to learn how to use them Indeed manufacturers often com modify their learning material thus making further profit by providing systems that require additional training The prioritisation of safety in car design came about because of consumer action stimulated by Nader s damning expos s Currently consumers of everyday things are unaware usability problems are avoidable People working in industry are themselves consumers of everyday things they may even be employed because of their eager following of technological fashion they are not immune from the cultural assumptions Although consumers could be focussed 8 towards usability the main driver for change will be from technologists Thus the rest of this paper is aimed at computer scientists arguing i the computer science of everyday things is embarassingly bad ii the computer science is easy to fix and to do so would have valuable benefits achieving environmental as well as usa
21. powerful than our competitors and we can af ford to finance just so much to get the leverage De spite Moore s Law users still take approximately the same sort of time to perform tasks If the growth of Moore s Law meant anything real for users we would already have had a huge computer revolution doubling every 18 months is a factor of a million after 30 years Social life has been transformed by transport yet the perfor mance gain is meagre compared to computer tech nology s 200 perhaps as little as ten The trans formation transport has made within such a small factor suggests that the tera factors for computers are measuring something of little significance to hu mans Humans do want to get to other places and they do want to move manufactured goods around the world but they do not need computers to have more memory or higher density processors What they do want is to get tasks done faster and better Computers are not doing that with anything like the spectacular improvements the proponents of Moore s Law would like us to believe except in a few specialised areas 10 Human activities have not been speeded up and certainly not speeded up by astronomical fac tors The growth described by Moore s Law focuses on technology not impact encourages industry to postpone worrying about usability encourages con sumers to try to keep up with changing fashions and all despite continual obsolescence 7 Ironi call
22. rams will run 25 faster in six months with you doing absolutely nothing In particular because memory gets cheaper programs get bigger Moore s Law removes pressure to im prove program quality programmers can always postpone addressing bloat Suppose by way of example a program is so complex that it will take 3 years to run If its pro grammers delay 18 months and then start there will be cheaper faster computers The program would still finish on the same date The program mers could have 18 months idling and still achieve the same goal Whatever you want to do you may as well do nothing to start with Enthusiasts of Moore s Law talk huge numbers Processor speed has improved by s memory has increased by m and wow the product has twice as many zeros But if we have more memory we need a faster processor just to take advantage of it in the same time If there is memory not accessed it is being used inefficiently thus improvement might be better quantified by the ratio m s which as sumes the computer is used to capacity in both speed and memory Talking huge products s x m while superficially impressive ignores usage Since the ratio m s whose dimension is time is more or less constant it explains why despite the naive view of Moore s Law computers still take as long to boot Hence Machrone s Law the com puter you want always costs 5000 It comes down to a business issue we want computers that are more
23. rical usability work is misplaced at least while it tries to understand or make user interfaces look better without changing the under lying way they are implemented There are numerous reasons why change will be difficult including 1 Some human factors researchers working in usability are explicitly trying to find ways of camoflaguing problems in user interfaces 19 2 Most human factors trained professionals do not understand computer science and there is a professional division between the two sub jects 3 The accurate computer science description of typical user interfaces is too hard to under take creating the impression that computer science cannot speak on the topic In con trast user problems are relatively easily ob served and measured This makes human fac tors salient but it describes symptoms of com puter science problems rather than helps un derstand or avoid their cause 4 Because all user interfaces involve people very similar empirical methods can be applied very widely In contrast almost all computational approaches are particular for example dis crete systems methods would be inappropriate for virtual reality techniques for speech are inappropriate for graphics and much harder to generalise In comparison to human factors experts computer scientists seem to know rel atively little about user interfaces in general 5 User interface design is done by industrial de signers again w
24. s solving the usability problem with their own work around Thus with hard effort they succeed and because of their investment in solving problems it becomes harder to question the overall appropri ateness of the device for their tasks Both calculators have memories which appear to function identically The button recalls the stored number and displays it but pressed twice in succession it sets the memory to zero The button adds the displayed number to memory and subtracts from the memory e We can assume that the memory is there for a purpose to store numbers and perhaps es pecially to store numbers that have been cal culated since other numbers are likely to be easily available How can a number calculated and displayed be stored in memory It is very hard to work out what to do Memory de spite high visibility keys giving the impression of simplicity is very difficult to use Arguably memory should save paper and help users do sums more reliably Yet most users especially those that need calculators would need a scrap of paper to work out how to avoid using paper to write down the number Evidently memory is not provided to make the calculator more usable but is a feature to increase p see Figure 1 Casio has been making calculators for a long time and the two calculators are not new in any way It is not obvious how Casio can justify either 2 Pressing adds the display to memory and only m
25. s easy since technology is getting better all the time After time t products get distinguished not by their performance which is more than adequate but by more subtle and harder to supply properties like usability For technologies like wrist watches we are long past the threshold and they are now fashion items that is chosen on criteria mainly other than technological But for many everyday things like word processors we should also be well beyond the crossover So why aren t word processors much better Manufacturers can increase consumers expecta tion of p by providing or promising new essential features it is in their interest to increase p because this postpones the crossover Thus many everyday things have numerous features a factor influencing their usability The slope of the graph obviously reflects Moore s Law Moore s Law eponymous of Intel s Gordon Moore 13 says that computer technical infrastructure improves by a factor of two every 18 months By infrastructure take your pick network bandwidth processor speed storage capacity progress is relentless We often do not wonder about Moore s Law beyond the excitement everyone hopes for better products tomorrow The law has been followed closely and by many companies If Moore s Law was an observation about scientific progress we would expect more variance We would not expect IBM Intel and Motorola to be neck and neck we wou
26. thical issues but see 11 which shows that car radios are a widespread unethical example of dangerous user interfaces and see 6 which discusses ethical de sign more generally 8 Conclusions We are caught up in a culture that accepts unus ability Sadly competent computer scientists seem aloof from the user interface This paper showed that a professional computer science of everyday things would help improve usability Computer sci entists routinely prove properties of their programs and worry about their efficiency and correctness why not apply these sorts of concern to the user interface This paper showed that benefits of us ability and a better environment will follow It is obvious that both computers and human users both run programs in languages such as CSP 7 the differences that might seem obvious in languages like Java disappear In particular users deserve as much attention in design of their programs i e the user interfaces as the comput ers get in their programs This paper showed that standard computer science can be applied to the user interfaces of everyday things User interface design is very much a proper part of computer science It is time to show users that higher standards are possible References 1 M A Addison and H Thimbleby Intelligent adaptive assistance and its automatic genera tion Interacting with Computers Volume 8 Number 1 pages 51 68 1996 2 J S Brown
27. y market churn the corrollary of Moore s Law encourages a low standard for the computer science of everyday things which in turn makes a causualty of usability 3 Consumer in action The automobile industry was changing rapidly in the 1960s and in some the problems of computer science at the turn of the 21st century reflect it In the 1960s some cars were badly designed and unsafe to drive As Ralph Nader exposed 14 22 the prevailing cultural assumption was that drivers had accidents and therefore drivers were respon sible for the behaviour of cars If an accident is driver error it is not the manufacturer s problem but is say a human factors or contextual prob lem If a parked car rolls down a hill an exam ple from 14 the driver should have applied the parking brake properly they should have turned the wheels so the car would roll against the kerb and so on they should be better trained the handbrake should have better affordance all perfectly constructive observations That the car has been badly engineered and has an unsafe park ing brake is thereby disguised Similar remarks could be made about pilot error and the generic excuse the human factor Thus we are persuaded that usability problems are human problems If users have usability prob 1Before the Industrial Revolution people moved between the speed of walking or of a horse say 5 to 70km h today you can unsafely and ex
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