Mental strain and the problem of repeated measurements

摘要

In the past, stress and strain arising form the execution of mentally demanding' tasks have been measured by means of surveys. Such methods require repeated investigation of the individual perceptions and valuations during task fulfilment to record time-dependent changes in strain levels. However, it is possible that the individual measurement procedures employed in surveys-as artefacts-may cause a change in the stress situation and subsequently in the resulting mental strain.