Mental Load

Dimpfel, W., Schober, F., and Spuler, M., The influence of caffeine on human EEC under resting conditions and during mental loads. Clinical Inverstigations 71, 197-207, 1993. 

For most normal operating conditions, the human operator can cope with the incremental additional mental load of inconsistencies, but during emergencies or other high-stress periods, each additional mental task is an opportunity for error. 

As a minimum, a 15-minute break from working should be taken after 2 hours of continuous computer work (CDC 1980 NIOSH 1981). Breaks should be more frequent as visual, muscular, and mental loads are high and as users complain of visual and musculoskeletal discomfort and psychological stress. With such intense, high-workload tasks, a work break of 10 minutes should be taken after 1 hour of continuous computer work. More frequent breaks for alternative work that does not pose demands similar to the primary computer work can be taken after 30 minutes of continuous computer work. Rest breaks provide an opportunity for recovery from local visual, musculoskeletal, and mental fatigue, to break from monotonous activities, or to engage in activities that provide variety in sensory, motor, and cognitive requirements. 

Lindstrom, K., and Leino, T. (1989), Assessment of Mental Load and Stress Related to Infotmation Technology Change in Baking and Insurance, in Man-Computer Interaction Research, MACIN-TER-II, F. Khx, N. A. Streitz, Y. Waem, and H. Wandke, Ms., Elsevier, Amsterdam, pp. 523-533. 

One of the most frequently applied measures in the field is EIR. It is used as an indicator of physical as well as mental load (see chap. 6, this volume). More refined analyses of evaluating cardiac activity use measures of EIR V, such as the power of the 0.1 EIz component and respiratory sinus arrhythmia (RS A), as very sensitive indicators of mental strain. Additional EIR can be calculated as the... 

Physical load induced by ambient temperature change During high physical and mental load in truck drivers Workload in ATC specialists (1983)... 

Respiration rate Mental load in a continuous memory task Backs and Seljos (1994) L... 

HRV (variation coefficient of IBIs) Mental load induced by speeding and swerving in car driving De Waard et al. (1995) F... 

Increased informationprocessing demands in HCI With mental load due to increased task difficulty... 

Richter, P, Wagner, T, Heger, R., Weise, G. (1998). Psychophysiologieal analysis of mental load during driving on rural roads—a quasi-experimental field study. Ergonomics, 41, 593-609. 

RoBger, R., Rotting, M., Unema, P. (1993). Experimentelle Untersuchung zum EinfluB von Leuchtdichteveranderungen und mentaler Beanspmehung auf den Pupillendurchmesser [Etqjerimental studies of the influence of changes of luminence and mental load on pupil diameter]. Zeitschrift fur Arbeitswissenschqft, 47, 141-147. 

The evaluation of cognitive processing, interference between tasks, and the effects of mental load in complex task environments. 

The same measure is often related to quite difieient concepts (e.g., HR has been proposed to reflect mental load, effort, resources, attention, emotion, etc.). 

Under high levels of mental load, extra energy is mobilized by mental effort, mostly in sitirations that are attention-demanding. Mental effort is used to improve or maintain performance efficiency. Under mental load. 

Gaillard, A. W K. (1993). Comparing the concepts of mental load and stress. Ergonomics, 9, 991-1005. 

The first study was performed at the University of Bonn, Germany. The purpose of the experiment was to study the cardiovascular effects of vagal blockade during the performance of a mental loading task. In this chapter, however, only data of the preblockade part of the experimental session are described. A comparison is made between a baseline (rest) period (5 minutes) and a task period (5 minutes) in which participants had to perform a memory search and counting task. The results of this study are summarized in Fig. 6.2. For details, see van Roon (1998). 

Kohlisch, O., Schaefer, F. (1996). Physiological changes during computer tasks Responses to mental load or to motor demands P/gonomics, 39, 213-224. 

Frankenhaeuser, M., Sterky, K., Jarpe, G. (1962). Psychophysiological relations in habituation to gravitational stess. Perceptual and Motor Skills, 15, 63-72. Gaillard, A. W K. (1993). Comparing the concepts of mental load and stress. Ergonomics, 36, 991-1005. 

Sanden, P.-O. (1990). Work in the control room. Studies of sociotecnical systems, job satirfaction, mental load and stress reactions. Unpublished doctoral dissertation, Stockholm University, Sweden. 

Sanden, P-0., Johansson, G. (1990). Job content and technology in process control Consequences for mental load andjob involvement (Report No. 725). Stockholm, Sweden Stockholm University, Department of Psychology. 

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