Disruptive Digital Workplace

Science | Psychophysiological Stress Measurement

INTERRUPTIONS AFFECT STRESS AND PRODUCTIVITY

Interrupting work does not only increase stress but directly and indirectly decreases the productivity of the individual and thus the productivity of the company. Emails are a common interruption. The change of activity between email as a communication medium (secondary task) and a work-based application (primary task) describes a common working practice. Interruptions and their effect on the digital workplace are subject of this Masters Thesis. It shows whether design decisions such as autonomy are of significant relevance.

PUPIL SIZE INDICATES STRESS

To ensure validity three different psychophysiological measuring instruments were compared with each other when measuring body reactions (stress). They provided an objective measurement in addition to the subjective self-assessment (NASA-TLX, Flow Short Scale, etc.). Even if the self-assessment and prevailing flow experience is needed in order to be able to measure stress and autonomy related with interruptions (cf. Galluch et. al. 2015: 6). The significance was confirmed by consistent reactions of pupil (eye tracker) and skin conductance in the phases of electrodermal activity.

Stress is caused by the imbalance 'between the abilities of the person and the demands placed by the environment.'
Ramakrishna Ayyagari, Varun Grover and Russell Purvis

Psychophysiological Measuring Instruments

at Evaluation-Lab (FOM) Munich to measure stress related to performance and time

EYE TRACKER

The eye tracking system used in the study detects both eyes separately to detect eye direction, duration and pupil size. Eye movement and pupil size is an indicator for mental stress.

With the help of the video recording with eye tracking it can be determined how often the test persons have checked the email notifications. The pupil size indicated whether the test persons were stressed.

FACE READER

With 500 key point and two cameras facial expressions can be recognized. In addition to a neutral emotion, the six basic emotions can be captured as happy, surprised, sad, disgusted, frightened and angry.

This project did focus on the investigation whether the lack of coping mechanisms leads to an increased feeling of fear.

ELECTRODERMAL RESPONSE

The skin conductance response is measured with two sensors attached to the outer surface of the non-dominant hand. Depending on how quickly the skin conductance changes and how long a certain value lasts, a distinction between workload and stress is possible.

The electrodermal activity was used to provide information on whether autonomy can reduce stress.

TEST PROCEDURE

01

Calibration

A calibration is necessary for each test person. The camera is able to detect the centre point of the pupil and the eye reflection point because the test persons follow points on the screen that are displayed one after the other in different places.

02

Experiment

To trigger time pressure a duration of ten minutes was set and emphasized that the primary and secondary task had to be completed during this time. After four minutes the test person received the email with the secondary task.

03

Debrief

After the experiment questions about the experiment were answered and feedback obtained on the basis of a semi-structured interview guideline. The interview was recorded, transcribed and evaluated with evaluation software.

PAUSING NOTIFICATIONS REDUCES STRESS

Test persons underestimate the frequency and impact of email notifications like decreased motivation, deceleration or reduced performance. Eye tracker and skin conductance showed that random pauses reduced the level of stress. It was even lower when test persons made a conscious decision to pause notifications. Further investigations are needed whether Thompson’s (2005) and Mark et. al.’s (2012) conclusions are true that deactivating notifications for a longer period may cause a feeling of isolation and fear to miss important information.

Distractions are not just a plague on our work sometimes they are our work. To be cut off from other workers is to be cut off from everything.
Clive Thompson (2005)

AUTONOMY LEADS TO STRESS

Design decisions such as autonomy can influence coping with stress, performance and time. Half of the test persons were given autonomy by pausing email notifications and the decision when to deal with the secondary task. The results of eye tracker and skin conductance showed that test persons with autonomy worked faster, achieved slightly better results, had higher flow experience but had in average higher stress levels over the entire test period.

YEAR 2015

CATEGORIES Assisted Working, Body Measurement, Digital Workplace, Media, Objective Research, Productivity, Quantitative Research, Science, Stress

CHALLENGE Interruptions and the effects on the digital workplace.

SOLUTION An experimental investigation with psychophysiological measurements and subjective self-assessment through different survey instruments. Stress, performance and time have been measured with three different psychophysiological measuring instruments: Eye Tracker, Face Reader and Electrodermal Response (EDR).

METHODS Psychophysiological Measurement, Eye-Tracking, Electrodermal activity (EDA), Face Reader, Online Survey, NASA-TLX, Flow Short Scale, Big Five, LPS, Anagram, Interview, Transliteration

TOOLS Microsoft Word & Excel, LimeSurvey, NYAN 2.0, Media Recorder, SPSS