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Evaluation of the Tactile Detection Response Task (TDRT) in a laboratory test using a surrogate driving set-up . Roland Schindhelm and Eike Schmidt. Outline. Characteristics of the TDRT method Background, research questions Method, experimental design Results Conclusions. - PowerPoint PPT Presentation
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Federal Highway Research Institute
Evaluation of the Tactile Detection Response Task (TDRT) in a laboratory test using a surrogate driving set-up
Roland Schindhelm and Eike Schmidt
Outline
1. Characteristics of the TDRT method
2. Background, research questions
3. Method, experimental design
4. Results
5. Conclusions
European Conference on Human Centred Design for ITS, June 2014, ViennaSchindhelm/Schmidt 2
Characteristics of the TDRT
TDRT is a method developed for the evaluation of information and control systems HMI (Engström et al., 2005).
TDRT measures effects of secondary task load on driver attention.
Main characteristics of the TDRT:• Stimuli-response task• Tactile stimuli presented by a vibrator
fixed to the participants shoulder• Stimulus duration 1 s, every 3 – 5 s• Manual response by pressing a finger
button
European Conference on Human Centred Design for ITS, June 2014, ViennaSchindhelm/Schmidt 3
Background
• 1 tactile mode (TDRT) and 2 visual modes are included in the DRT method.
• Standardization of DRT method in progress (ISO/CD 17488).
• BASt is involved in coordinated international studies which aim at supporting the ISO Task Force in developing the DRT standard.
• Main research questions are related to– the use of DRT in different driving set-ups– difference in results obtained with the three DRT modes– sensitivity and specifity of the DRT modes
European Conference on Human Centred Design for ITS, June 2014, ViennaSchindhelm/Schmidt 4
Research questions of the BASt study
The BASt DRT study focuses on the Tactile DRT (TDRT).
• To what extent is the TDRT sensitive to systematic manipulation of task load for different types of tasks?
• How does the TDRT affect secondary task and primary task performance?
Selection of Research questions from presentations given by Engström and Young, Yokohama Meeting 2012
European Conference on Human Centred Design for ITS, June 2014, ViennaSchindhelm/Schmidt 5
Method of the BASt study
Laboratory test performed in July/August 2013• Subjects: 10 female, 12 male, age 19-64 (M=41.7), licensed
drivers• Single-task and multiple-task scenarios derived from selected
combinations of the following independent factors:– Type of primary task (visual, auditory tracking)– Type of secondary task (N-back Task, SuRT)– Task difficulty (easy, hard)– Use of TDRT (without, with)
• Within-subject design• Order of task scenarios was counter-balanced across subjects• Duration per trial: 60 sec.
European Conference on Human Centred Design for ITS, June 2014, ViennaSchindhelm/Schmidt 6
Tasks, independent variables
• Driving task surrogate as a primary task:
Continuous Tracking Task (semi-static)Manual control of the cursor viasteering wheel- 2 modalities of feeding back
tracking deviation(visual, auditory)
- 2 difficulty levels (easy, hard)
Easy Hard
European Conference on Human Centred Design for ITS, June 2014, ViennaSchindhelm/Schmidt 7
Tasks, independent variables
• Secondary tasks:
SuRTVisual search; manual control of the cursor via key pad- 2 difficulty levels (easy, hard)
N-Back task Auditory stimuli; cognitive processing; vocal response- 2 difficulty levels (easy, hard) 0-Back 1-Back
Easy Hard
European Conference on Human Centred Design for ITS, June 2014, ViennaSchindhelm/Schmidt 8
Easy Hard
Experimental set-up
European Conference on Human Centred Design for ITS, June 2014, ViennaSchindhelm/Schmidt 9
Dependent variables, indicators
• TDRT:– mean response time– hit rate
• Tracking task:– root mean square deviation
• N-Back task:– percentage of correct answers
• SuRT:– mean response time
European Conference on Human Centred Design for ITS, June 2014, ViennaSchindhelm/Schmidt 10
0100200300400500600700800900
1000
Mea
n re
spon
se t
ime
(ms)
p < .01 n.s. n.s.n.s.
Secondary Task
easy hard easy hard
N-Back SuRT
Primary Task easy hard easy easy hard
Visual Tracking Aud. Tracking TDRT Tactile DRT
TDRT response time in different task scenarios
European Conference on Human Centred Design for ITS, June 2014, ViennaSchindhelm/Schmidt 11
0
500
1000
1500
2000
2500
without TDRT
with TDRT
Roo
t m
ean
squa
re d
evia
tion
(p
xl)
p < .05n.s.
p < .01 p < .001
n.s.p < .05
Secondary Task hard hard N-back SuRT
Primary Task easy easy hard easy hard Visual Tracking Auditory Tracking
Effect of TDRT on primary task performance: - Tracking deviation
European Conference on Human Centred Design for ITS, June 2014, ViennaSchindhelm/Schmidt 12
5
6
7
8
without TDRT
with TDRT
Mea
n re
spon
se t
ime
(s)
p < .01
Secondary Task SuRT, hardPrimary Task Visual Tracking, easy
Effect of TDRT on secondary task performance:- SuRT response time
European Conference on Human Centred Design for ITS, June 2014, ViennaSchindhelm/Schmidt 13
Secondary Task N-back (hard)Primary Task Visual Tracking (easy)
Effect of TDRT on secondary task performance:- N-back percentage of correct answers
0102030405060708090
100110
without TDRTwith TDRT
Perc
enta
ge o
f co
rrec
t an
swer
s (%
)n.s.
European Conference on Human Centred Design for ITS, June 2014, ViennaSchindhelm/Schmidt 14
Conclusions/1
• Sensitivity in triple-task scenarios:“Primary T. + Secondary T. + TDRT”
Sensitivity of TDRT to different load levels of cognitive secondary tasks could be confirmed (N-Back easy vs. hard).
TDRT seems to be not sensitive to load levels of secondary tasks which primarily demand for visual-manual resources (SuRT easy vs. hard).
TDRT is sensitive to secondary task types which vary in type of resource demands (cognitive vs. perceptual-motor)
European Conference on Human Centred Design for ITS, June 2014, ViennaSchindhelm/Schmidt 15
Conclusions/2
• Sensitivity in dual-task scenarios: “Primary T.+ TDRT”
TDRT seems to be not sensitive to load levels of the surrogate driving task (bendiness of the tracking path).
TDRT is sensitive to primary task types which vary in cognitive resource demands (auditory-cognitive-motor vs. visual-motor demands of tracking task).
European Conference on Human Centred Design for ITS, June 2014, ViennaSchindhelm/Schmidt 16
Conclusions/3
• Intrusiveness:
There are indications of the TDRT’s intrusiveness on primary task performance (tracking deviation).
No clear picture for intrusiveness of TDRT on secondary task performance. Intrusiveness of TDRT seems to depend on type of secondary task:
No intrusion on N-Back performance Intrusion on SuRT performance
European Conference on Human Centred Design for ITS, June 2014, ViennaSchindhelm/Schmidt 17
Conclusions/4
• Further research recommended:
Interference between TDRT and secondary/primary task due to motor task demands.
Intrusiveness of TDRT on primary task and secondary task performance:
Comparative studies on degraded vs. normal task performance.
Limitations of applicability of TDRT (e.g. in on-road tests).
Sensitivity of TDRT to load levels of other secondary task types (generic tasks; real tasks)
European Conference on Human Centred Design for ITS, June 2014, ViennaSchindhelm/Schmidt 18
Federal Highway Research Institute
Thank you for your attention!
European Conference on Human Centred Design for ITS, June 2014, ViennaSchindhelm/Schmidt 19
Schindhelm/Schmidt 20
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European Conference on Human Centred Design for ITS, June 2014, Vienna