Applicability of location compatibility to thearrangement of display and control in

human – vehicle systems: Comparison between young and older adults

ATSUO MURATA and MAKOTO MORIWAKA

ErgonomicsVol. 50, No. 1, 15 January 2007, 99–111

Introduction

Sharing of attention may lead to dangerous situations• Driving a car places a characteristically heavy workload on

visual perception, cognitive information processing and manual responses. (Wickens et al. 1983)

• With the growth of intelligent transportation systems, such as car navigation systems or hands-free mobile phones, driving is becoming more and more complex. (Noy 1997)

• In order to simplify operation and reduce time spent on the secondary tasks, it is essential that the display – control relationships be compatible.

Location (display – control) compatibility principle (Fitts and Seeger 1953, Wickens et al.

1998)

• The location of controls should be decided along with the

location of its related display. (Wickens et al. 1998)

• 刺激與反應間（控制器與顯示器位置）的關係與操作者預期的一致性程度，由於產生其反應，強烈影響人員績效

• 納入產品設計，優點為：– 學習更快更容易– 反應時間短– 失誤較少– 操控更精確

Introduction

Displays and controls in automobiles

• Most research discusses design of the display or the control, but not the way in which they are to operate together, which includes effects of compatibility.

• Lambel et al. (1999a,b) discussed the relationship between display location and performance in car driving situations.– Display 位置會影響駕駛者偵測週遭環境的能力

• Waller and Green (1997) pointed out a lack of consensus as to where the control should be located.

Introduction

Effects of driver age• Many reports suggesting that older adults exhibit deficits in

various cognitive-motor tasks. (Goggin et al. 1989, Goggin and Stelmach 1990, Stelmach and Nahom 1993)

• Imbeau et al. (1993) discussed how the aging factor affected display design and driving performance.– presented a model that can predict performance

• Smith et al. (1993) pointed out that design approaches and data used in automobile design are mostly for a young population.– The characteristics and problems of older drivers, including

physical and motor, sensory and cognitive changes.

Introduction

• The location compatibility principle is consistently applicable to both young and older populations?

• In this research, the applicability of location compatibility to the design of display and control systems was explored as a function of age.

Introduction

• Explore display location, together with the aging factor, affects the performance of primary and secondary tasks.

Participants• Older group:

– 10 male, age from 65-76 years– held driver license for 30–40 years

• Young group:– 10 male, age from 21-24 years– held driver license for 1-3 years

• Visual acuity of the participants were matched and more than 20/20.

• Doesn’t had any orthopedic or neurological diseases.

Method

Apparatus• PC

– to pursuit tracking system– used to display speedometer and operational information– used to enable the participant to operate switches

• CRT– 15-inch CRT in front of participant – 4.1-inch CRT placed in left of the participant

Method

• Switch– included numerals from 1 to 5 and arrows (up, down, right and

left plus enter switch)– placed around steering wheel and to the left of the participant– The numeral and arrow switches were fixed on the left and right

sides

Method

• Display– placed in front of the participant

• displays a task that the participant must perform using the switches

• informs the participant of the current state as the task is performed

• group of selectable menus

– placed left of the participant• includes similar information of the front CRT• speedometer and the tachometer are not depicted on there

Method

• The front CRT

Method

Display of task Display of state

State icons

AM/FM CD/MD

Task • Primary task (tracking task)

– 1-D with the horizontal position of a target line changing pseudo-randomly

– follow the movement of a target line with the shorter vertical line controlled by a steering wheel

– position of the vertical target line changed every 1.5 s and sampled every 0. 1 s

Method

Task • Secondary task – there were three type

Method

• Secondary task

Method

Design• Tracking task

– experimental factor: age (young and older adults)

• Secondary task– experimental factor:

• age (young and older adults)

• location of switches (two levels: steering wheel; and left side of the participant)

• location of display (two levels: front; and left)

– two repetitions of each condition each contained a total of 20 trials

– inter-trial interval was 4 s

Method

Procedure• Participants were allowed to practice before performing

experimental tasks

• single-task conditions– single tracking task was continued for 3 min– secondary task consisted of 20 switch-pressing trials.

• dual-task conditions– Two session– ranged from 2 to 9 min– required to keep the primary task stable– perform the secondary task as fast and accurately

Method

Experimental measures• mean root mean square tracking error

– between a moving target and a controlled vertical cursor

• mean completion time of 20 secondary tasks

• mean percentage correct performance of the secondary task

Method

Tracking error• Single tracking task

– no significant main effect of age

• Dual task condition– Only significant main effect of age (F(1,18) = 24.08, p < 0.05)– older group (19.08 ± 1.54) larger than young (16.11 ± 1.47)

• No effect of switch or display location on tracking performance.

• The secondary task interfered with the primary tracking task.

Result and Discussion

Percentage correct secondary task responses• Single secondary task

– Only significant main effect of age (F(1,18) = 18.923, p < 0.01)– Older population (0.79 ± 0.11) was lower than young population

(0.93 ± 0.06).

• Dual task condition• Only significant main effect of age (F(1,18) = 27.56, p < 0.01)– Older population (0.77 ± 0.19) was lower than young population

(0.94 ± 0.08).

Result and Discussion

Completion time of secondary tasks• Single secondary task

– significant main effect of age (F(1,18) = 20.206, p < 0.01)– significant interaction of display location × switch location

(F(1,18) = 14.369, p < 0.01)– significant triple interaction of age × display location × switch

location (F(1,18) = 12.470, p < 0.01)

Result and Discussion

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Completion time of secondary tasks• Dual task condition

– significant main effect of age (F(1,18) = 22.239, p < 0.01)– significant interaction of display location × switch location

(F(1,18) = 12.99, p < 0.01)– significant triple interaction of age × display location × switch

location (F(1,18) = 10.5, p < 0.01)

Result and Discussion

FD = front display

LD = left-side display

SS = steering wheel-mounted switch

LS = left-side switch

Result and Discussion

Mean dual-task efficiency

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Completion time of secondary tasks• young group

– only a main effect of switch location was significant (F(1,9) = 10.69, p < 0.01)

– The switch location for left-side display (F(1,9) = 13.28, p < 0.01) and for front display (F(1,9) = 6.7, p < 0.05)

– the steering wheel-mounted switch was shorter than that for the left side switch

principle was applicable to the front display

Result and Discussion

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Completion time of secondary tasks• Older adults group

– significant display location × switch location interaction (F(1,9) = 11.98, p < 0.01)

– switch location for the left-side display was found to be significant (F(1,9) = 6.28, p < 0.05)

• left-side switch shorter than that of the steering wheel-mounted switch

– switch location for the front display was also found to be significant (F(1,9) = 12.08, p < 0.01)

• steering wheel-mounted switch shorter than that of the left-side switch

location compatibility principle was applicable to both front and left-side

displays.

Result and Discussion

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• With the young population– steering wheel-mounted switch is processed faster than the left-

side switch irrespective of the display location– completion time of the SS(FD) was shorter than LS(LD)– The location compatibility did not apply to the left-side display

• older adults– SS(FD) and LS(LD) led to shorter completion time– These tendencies were common to both single- and dual-task

conditions.

• These differences can be accounted for by the declined cognitive slowing, declined working memory capacity and declined motor function of older adults

(Goggin et al. 1989,Goggin and Stelmach 1990, Stelmach and Nahom 1993)

Result and Discussion

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• This might be because the compatibility principle (proper grouping) compensated for any decline in perceptual and cognitive functions and motor functions (Stelmach and Nahom 1993, Smith et al. 1993)

• proper grouping of switch and display locations, enhanced the performance in particular of the older adults.

• For the young participants, this principle was true only for the front display.

reasons for this require further research

Result and Discussion

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The end

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