Human Efficiency




Leonard Verhoef.
Contact
for    interface & web public transport In Dutch.  future systems etcs mmi with e.g.

Presenting numbers to teachers, train drivers and travellers, article

Logo: IIID Leonard Verhoef
Paper presented at: Application of Information Design 2008
Mälardalen University, Eskilstuna and IIID
25-28 June 2008
Last changes February 2009.


Once upon a time the interface to control quantities had four options: 'one', 'two', 'three' and 'many'. Today we have an infinite number of words for quantities. In addition, the very same numbers are used for very different professions such as: teaching, train driving and travelling. From a psychological point of view there are more similarities in the way humans perform these tasks.

To top. 		    
  • These professionals use the same eyes for perceiving written numbers and they write these numbers in the same way.

  • They all evaluate these numbers as good or bad using the same brains and more or less take the same type of decisions, for instance: increase or decrease learning speed, walking speed or trainspeed.

  • Even on an emotional level they act similar when it is clear that the numbers are far too low.
    		•      Having so many similarities in human functions and tasks, shouldn't the interfaces for these professionals be more similar, not only on a lower perceptual level (readability), but on a higer cognitive level too?


    Task analysis Theory
    A common professional action is comparing current student performance/trainspeed/walking time against a target performance/speed/time. In all cases the actions of the professionals are:

  • Perceive the current value.

  • Determine the target value.

  • Calculate the difference.

  • Make adjustments based on the reliability of the values.

  • Take into account the trend.

    • Examples

    Human activities

    Teacher’s
    Activities

    Train driver’s
    activities

    Traveller’s activities

     

    Obtain information

     

     

    Perceive actual value:

    student’s performance now;

    train speed now;

    time now.

     

    Target value:

     

    performance level planned;

     

    train speed below safe speed and above scheduled speed;

     

    time of departure.

    Difference:

    <target; =target; >target.

     

    Evaluation

     

     

    Focus attention if:

    student is below target;

    speed is above safety target;

    traveller might miss his train.

    Trend, e.g.:

    mostly student catches up;

    mostly at next station I can gain 2 minutes;

    mostly this departure is delayed.

    Reliability

    good or bad test

    speedometer +/-5km/h

    clock incorrect.

     

    Action

     

     

    If >0:

    next subject to learn;

    now: slow down to save energy (next time delay departure);

    get coffee next time: stay in bed longer.

    If =0:

    next subject to learn;

    maintain speed;

    continue walking.

    If <0:

    remedial action;

    increase speed/ brake shortly

    run.

    If <<0:

    call student; next time test in an earlier phase;

    brake now!;

    decide now: run fast or coffee.

    If  too much <0:

    remove student from course;

    safety system brakes;

    train missed, appointment missed.



    Obtain information Obtain information, readable numbers
    Theory
    Perceptual psychology has specified how to present numbers in a readable way. This includes the use of leading zero's, capitals, underline, fonts and digitally presented characters (segment and matrix fonts). With these specifications it is easy to find the best design to present a student’s score, trainspeed and the time of departure.

    To top.     		    
    Examples
    For all professionals leading zero's, underlining, non-serif characters and digitally characters, if possible, should not be used.



    Obtain information, calculate difference

    Theory
    All professionals need to know the difference between current number and target number. Analysis of interfaces shows that it often is not understood that it is the computer who should perform this computing.

    Examples
  • Keuning and Roding (2008), for instance, suggest the passengers should perform the computing. So does Netherlands Railways on this indicator.
    		•      Metro and bus indicator Amsterdam Arena
    Indicator for trains and busses, Amsterdam Arena, 2008 Time of departure for trains, passengers have to calculate time to departure Time to departure for metro's, no calculation for passengers.



  • Difference between current trainspeed (white hand, 130 km/h) and maximum trainspeed (white border, 150 km/h) is indicated in such a way that the high speed train driver does not need to calculate the difference.

    To top.
    		•      ETCS speed indicator
    Interface for trainspeed and safety, ETCS, 1995


    Obtain information, presentation using graphics

    Theory
    One lesson perceptual psychology teaches us, is that human eyes and human brains are not built for processing numbers. For instance, it is easy to survive in nature without being able to notice the difference between the character '1' and the character '7'. Cognitive psychology learns that the visual presentation of a concept should be compatible with the concepts that the user has in mind. Seven is more that one and consequently it is better to present 7 larger. However, the visual difference (form and size) between 1 and 7 is small. One easily can increase compatibility by presenting numbers and their relations using graphics.

    To top.     		    

    Examples

  • A graphical presentation of speeds is the best way and most commonly used, e.g. a round clock.

  • The best presentation for a time of departure would be a traditional clock too. This however, is uncommon. Time of departure and time to departure never are presented in a integrated graphical way as trainspeeds for high speed train drivers is integrated graphically. See the figure.


    • Evaluation Theory
    The difference between the current value and the target value has to be evaluated. All professionals do this in the same way, even professionals of professions that do not yet exist.     		    
    After the evaluation action might be needed. A more detailed analysis of control of attention can be found in Verhoef (2006).


    Evaluation, no attention
    Theory
    The variable is whitin limits. No attention required, no unexpected information, user can consult information whenever he wants.

    Examples

  • Teacher: Pupil Bill passed the test and acquired the learning aim counting to 100 (Teacher examples here are simplifications of a more complex Learning Object Control System).
    •  

    Performance learning aim: counting

    Bill

     

     

     

     to 5

     

     

     

     to 10

     

     

     

     to 15

     

     

     

     to 20

     

     

     

     to 100

     

     

     
     
  • Train driver: No problem, current speed below braking curve.
    ETCS, indication: braking will be needed shortly.

  • Traveller: No hurry, you will catch your train.
    Public transport indicator, board shortly.

  • Pilot of the passenger shuttle to Mars: No obstacles ahead.


    • Evaluation, attention shortly!

    Theory
    The variable has reached a level at which attention is required within a short period of time

    Examples
  • Teacher: Pupil George's performance not ok, yet, but acceptable.

    Performance learning aim: counting

     

    1

     

     

     

     to 5

     

     

     

     to 10

     

     

     

     to 15

     

     

     

     to 20

     

     

     

     to 100

     

     

  • trainspeed OK, no actions required.
    ETCS, indication trainspeed ok.

  • Traveller: Sufficient time, go to train, don't buy coffee before boarding the train
    Public transport indicator, board shortly.

  • Pilot of the passenger shuttle to Mars: Meteorites on current course, change of course will be needed in a few hours.

    • Evaluation, attention now!


    Theory
    The variable has reached a level which is not ok, unacceptable, action now! Examples

  • Pupil John's performance insufficient, remedial action is needed immediately before proceeding. Performance learning aim: counting

    Performance learning aim: counting

     

     

    John

     

     

     

     to 5

     

     

     

     to 10

     

     

     

     to 15

     

     

     

     to 20

     

     

     

     to 100

     

  • trainspeed is too high, train might pass next signal at danger, brake now!
    ETCS, indication: braking will be needed shortly.

  • Train will depart shortly, run now!
    Public transport indicator, board now!


  • Pilot of the passenger shuttle to Mars: Collision with meteorites imminent, change course now!

    Evaluation: game over

    Theory
    The variable exceeded it's acceptable level. Despite warnings no action has been taken by the professional. The system takes action or a disaster occurs. Examples

  • Pupil Mary will not finish this course. She has to start again or abort this course. Performance learning aim: counting

    Performance learning aim: counting

     

     

     

    Mary

     

     

     

     to 5

     

     

     

     to 10

     

     

     

     to 15

     

     

     

     to 20

     

     

     

     to 100

  • The train will pass the signal at danger. However, probably the train's safety system performs a system safety stop. The system assumes that the driver is incapable of performing his task. The ticket collector checks the driver.
    ETCS, indication: braking will be needed shortly.

  • Train departed without the passenger.
    Public transport indicator, sufficient time for boarding.

  • The meteorites would hit the shuttle. However, probably the shuttle's safety system changes course. Pilot is dismissed.

    To top.

    • Next step Theory
    The examples given were from real live projects and had to take account of traditional practice and available technology. We only could show that the interfaces for these professionals are similar in the way colour was used to control attention. When designed from psychological top, to professional bottom there would be much more similarities. Finding these similarities would reduce interface design effort substantially. However, this will not lead to unemployment of designers. So far the tasks discussed were one dimensional. There is one dimension of learning objects, only a safe trainspeed is taken into account and the traveller focuses only on catching this train. Tasks are becoming more and more complex and so will the interfaces supporting professionals performing their task.

    To top.     		Examples

  • Teaching arithmetic is not sufficient anymore. The pupil has to be taught to do it in a creative way and in harmony with other pupils.

  • Driving in time is not the only aim of a train driver. He should do so in a safe, economic, comfortable and environmental friendly way.

  • The number of routes and options for a specific public transport trip increases too as well as the options for payment, price and services. In most cases the content and the interfaces are not structured in a one dimensional but chaotic way (Verhoef, 2007). The well known computer desktop is physically two dimensional, but what these dimensions stand for is unknown yet, even after several decades of usability science.


    • References

    Keuning en Roding, (2008). DRIS: lezen en wegwezen, Verkeerskunde, no 4, 27 mei.

    Rookmaaker, D.P., Verhoef, L.W.M., Vorderegger, J.R. & Maessen, E.J.M., (1994). The presentation of speed control information of ETCS train drivers, Paris, in: SNCF Dir. de la Recherche, pag. 959-964, in: World Congress on Railway Research.

    Verhoef, L.W.M. (2006). GUI, webontwerp, psychologie en human efficiency. Utrecht: Human Efficiency. book in Dutch: www.humanefficiency.nl/gui.shtml course in English: www.humanefficiency.nl/course.shtml

    Verhoef, L.W.M. (2009). Why designers can’t understand their users; developing a systematic approach using cognitive psychology. Utrecht, Human Efficiency.  www.humanefficiency.nl/designers_understanding.shtml

    To top.

    Contact



    cognitive psychology, interface design, mmi, userfriendlyness, usability, web page design    		 Leonard Verhoef.
    +31 (30) - 231 44 97
    Parkstraat 19
    3581 PB Utrecht
    Nederland

    humanefficiency.nl
    verhoef@humanefficiency.nl

     Chamber of commerce, trade register, subscription number: 39057871.