Testing Open-Source Implementations for Detection ...

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Sep 12, 2014 - Implementation of the DRT protocol on an Android smartphone .... We will track what the smartphone is doing (vibrate, subject response) in ...
Institute of Ergonomics

Technische Universität München

Testing Open-Source Implementations for Detection Response Tasks Michael Krause, Antonia Conti, Moritz Späth, Klaus Bengler Institute of Ergonomics Technische Universität München, Germany

Institute of Ergonomics

Technische Universität München

Overview • Motivation • Experiment/Setup • Results • Conclusion • Outlook

12th September 2014

Michael Krause, Interaccion 2014

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Institute of Ergonomics

Technische Universität München

Motivation • Measuring the effects of cognitive workload ISO/TC 22/SC 13/WG 8 ISO/CD 17488 Detection Response Tasks (DRT) => continuous stimulus - reaction test • Basic concept: If the reaction time (RT) for the DRT is prolonged the subject likely has a higher cognitive workload • Expensive proprietary equipment is available => Let’s try it free and OpenSource (modifiability often need for experiments, able to trace back functionality, no black box)

12th September 2014

Michael Krause, Interaccion 2014

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Institute of Ergonomics

Technische Universität München

Arduino-DRT • Implementation of the DRT protocol on an Arduino microcontroller board • Documentation, schematics and source code available: http://www.lfe.mw.tum.de/arduino-drt/

12th September 2014

Michael Krause, Interaccion 2014

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Institute of Ergonomics

Technische Universität München

Smartphone - Mobile Detection Task (MDT) • Implementation of the DRT protocol on an Android smartphone • The experimental setup via smartphone is not within the ISO drafts! Therefore, we call it Mobile Detection Task (MDT) • Documentation, schematics and source code available: http://www.lfe.mw.tum.de/mdt

12th September 2014

Michael Krause, Interaccion 2014

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Institute of Ergonomics

Technische Universität München

Comparision

(Regular) Arduino DRT

Smartphone MDT

Visual stimulus

LED on a cap

Smartphone display

Tactile stimulus

Tactor taped to shoulder

Palm rest on smartphone loosely

Response

Reponse button on the finger

Thumb on touch screen

12th September 2014

Michael Krause, Interaccion 2014

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Institute of Ergonomics

Technische Universität München

Procedure • Conditions (3) – Single condition: baseline (Detection Response Task only) – Double condition: DRT + Driving (AAM) – Triple condition: DRT + Driving (AAM) + Cognitive task (2-back task) • On different systems (Arduino-DRT, Smartphone-MDT) • In different modes (Visual or Tactile) • Full factorial, randomized, within-subject design • Each condition 1 Minute (~15 stimuli) 12th September 2014

Michael Krause, Interaccion 2014

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Institute of Ergonomics

Technische Universität München

Static Driving Simulator

12th September 2014

Michael Krause, Interaccion 2014

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Institute of Ergonomics

Technische Universität München

Participants • 36 subjects (50% male; 50% female) • Age: 19 - 31 years; M = 22 (SD 3) • Mainly students and researchers

12th September 2014

Michael Krause, Interaccion 2014

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Institute of Ergonomics

Technische Universität München

Reaction times for tactile stimulus presentation on both systems

12th September 2014

Michael Krause, Interaccion 2014

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Institute of Ergonomics

Technische Universität München

Reaction times for visual stimulus presentation on both systems

12th September 2014

Michael Krause, Interaccion 2014

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Institute of Ergonomics

Technische Universität München

Effect size

12th September 2014

Michael Krause, Interaccion 2014

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Institute of Ergonomics

Technische Universität München

Effect size

about the same effect sizes

12th September 2014

Michael Krause, Interaccion 2014

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Institute of Ergonomics

Technische Universität München

T-test probabilities • Higher bar => lower probability (logarithmic)

12th September 2014

Michael Krause, Interaccion 2014

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Institute of Ergonomics

Technische Universität München

T-test probabilities • Higher bar => lower probability (logarithmic) • Smartphone setup typically 1-2 orders of magnitude inferior and fails in one condition to reach alpha level 5% (5.2%)

12th September 2014

Michael Krause, Interaccion 2014

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Institute of Ergonomics

Technische Universität München

Correlation of individual subject‘s RTs between conditions

12th September 2014

Michael Krause, Interaccion 2014

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Institute of Ergonomics

Technische Universität München

Correlation of individual subject‘s RTs between conditions

used smartphone setup do not reach high correlations of RTs

12th September 2014

Michael Krause, Interaccion 2014

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Institute of Ergonomics

Technische Universität München

Conclusions • Tests with the smartphone (MDT) shows the same trend (longer RTs) as the classical DRT and can detect cognitive effort. Nevertheless, for very similar conditions a higher number of participants is needed. Regular DRT setup is significant more quickly, with less participants and measurement points, than the MDT. • Constant low correlations in RT of the test subjects between similar experimental conditions for MDT indicates, that simple attachment of the smartphone to the steering wheel is a lower quality setup relative to the classical DRT setup => Improving the setup/mounting seems crucial. 12th September 2014

Michael Krause, Interaccion 2014

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Institute of Ergonomics

Technische Universität München

Outlook (MDT improvements for the next experiment) 1) External response button

2) Mounting direct to the test subject. Similar to a regular DRT setup

12th September 2014

Michael Krause, Interaccion 2014

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Institute of Ergonomics

Technische Universität München

Outlook (Follow-up Experiment)

• Questions/Motivation: Is the correlation between similar experimental conditions higher with the new setup; is the new setup better? We will track what the smartphone is doing (vibrate, subject response) in parallel with a microcontroller. Is the (in)accuracy of the smartphone sufficient?

12th September 2014

Michael Krause, Interaccion 2014

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Institute of Ergonomics

Technische Universität München

Testing Open-Source Implementations for Detection Response Tasks

Michael Krause, Michael Krause

12th September 2014

Antonia Conti,

Moritz Späth,

Klaus Bengler

Graduate Research Assistant Faculty of Mechanical Engineering Institute of Ergonomics Boltzmannstraße 15 D-85747 Garching Tel +49 89 289-15404 Fax +49 89 289-15389 [email protected] http://www.ergonomie.tum.de Michael Krause, Interaccion 2014

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