Measuring vigilance level in demanding work setting
A.S. Smit1, J. Benito2, J. Troost2 and C.H.M. Nieuwenhuis1
1Decis Lab, Thales Research & Technology, Delft, The
Netherlands
2Thales Nederland, Hengelo, The Netherlands
Vigilance level strongly affects performance, especially on cognitively
demanding tasks. Therefore, it is important to be able to determine the
level of vigilance of individual people in many work settings. For example,
an operator in a control room setting often needs to work in cognitively
demanding situations under high mental work load. Traditionally, the level
of vigilance has been determined using three different kinds of measures:
physiological, performance and subjective. As they all have their own
drawbacks, more stable measures can be obtained when they are simultaneously
collected from different sources. It has proven very difficult to use
physiological variables as indices of vigilance level on an individual
basis. Many physiological parameters are very useful for distinguishing
between experimental groups, but it appears rather difficult to determine
a persons vigilance on the basis of physiological data only. Moreover,
EEG equipment can be rather intrusive in a work setting and EEG measurements
are vulnerable to many artefacts. It has been demonstrated that vigilance
can be estimated with much simpler measures such as subjective alertness
scales and performance measures. In fact, on group level subjective vigilance
questionnaires can be as reliable as physiological data when determining
the level of vigilance. Subjective alertness can be assessed with a relatively
small set of questions and performance measures can be acquired during
tasks that are non-intrusive in the work environment and do not need to
take much time to perform. We will describe a method for measuring vigilance
based on the aggregation and fusion of individual measures. This method
will not use physiological measures, but focuses on more easily applied
behavioral measures, both subjective and objective, which can easily be
derived in a work setting. The long-term goal is the development of a
method that can be used in fully operational situations in the work setting,
in order to enhance total system performance.
Paper presented
at Measuring Behavior 2005
, 5th International Conference on Methods and Techniques
in Behavioral Research, 30 August - 2 September 2005, Wageningen, The
Netherlands.
© 2005 Noldus
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