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Psychological job hazards — more common than you think
involved responding to software generated alarm messages, and invoke network changes via a command language, to regulate input/output traffic flow. Data were collected using activity analysis sampling, command language analysis, and error analysis in order to obtain statistics on the following factors: operator work load, alarm volume per hour, operator response time per alarm, system acknowledgement time, error type and frequency. The results indicated that the alarm volume required an operator response time of 90 s, which over-loaded the operators. Recommendations to allocate to the software additional monitor and control tasks, and to modify the software interfaces, reducing the alarm volume, were implemented. The results of a second experiment, conducted to measure the effects of the software changes, identified a substantial improvement in operator performance, a reduction in operator workload, errors, and alarm volume. These findings led to the confirmation of several human factors principles applicable to interface design. 11.3.5 (78064)
Kopala, C.J. The use of colour-coded symbols in a highly dense situation display. In:
Compass for Technology, Proceedings of the 23rd Annual Meeting of the Human Factors Society, Boston, Massachusetts, Oct 2 9 - N o v 1 1979, Edited by C.K. Bensel, pp 3 9 7 - 4 0 1 . The effectiveness of redundant colour-coding for displays used by highly-loaded operators performing a series of complex tasks has never been clearly demonstrated. Pilot flight performance and threat recognition performance using two coding conditions for a threat display were compared in a simulated mission. One coding condition consisted of shapecoded symbols, the other of symbols that were both colour- and shape-coded. Redundant colour-coding was found to significantly reduce both response time and error rate.
Factors affecting perceptual-motor performance 11.3.6 (78077)
Smith, W.K. A review of literature relating to visual fatigue. In: Compass for Technology,
Proceedings of the 23rd A nnual Meeting of the Human Factors Society, Boston Massachusetts, Oct 2 9 - N o v 1 1979, Edited by C.K. Bensel, pp 3 6 2 366.
The design of workstations with visual displays has become the subject of considerable interest and concern during the past few years. One area of concern relates to the assumption that long term viewing of such displays at close focal distances may contribute to visual fatigue. A second is the effect on the human visual system of the frequent changes in surface illumination associated with display units used in combination with hard copy documents. As a consequence of these and other concerns, the popular press has published articles that have aroused the interest of various scientific organisations regarding the subject of these effects. This paper discusses a review of some of the literature regarding a limited aspect of this issue, namely the accommodation and pupillary systems as they relate to long term viewing of visual display units.
Blue-collar workers in Sweden relate psychological strain chiefly to physical factors in the working environment. White-collar employees more frequently mention psycho-social reasons. But mental stress factors also contribute to their enjoyment of their jobs. Curt R. Johansson, whose division in the Psychology Department of Lund University specialises in labour-related studies, summarises a number of investigations on the psychological and physical hazards in Sweden's working environment.
Physiology, anthropometry and biomechanics 11.3.9 (78138)
Saha, P.N.,
et
al
An acceptable workload for Indian workers. Ergonomics, 1979, 22.9, 1059-1071.
11.3.7 (78079)
Conrads, H. Yon. An ophthalmologist's evaluation of work at visual display units (Die Beurteilung der Arbeit an Datensichtgeraten aus Augenarztlicher Sicht). (In German.) Zentralblatt fur Arbeits-
medizin, Arbeitsschutz und Prophylaxe, Sep 1978, 28.9, 2 5 6 - 2 5 8 ; abstr in:
CIS Abstracts (CIS 79-1007). Work at CRT display terminals may cause organic and functional eye disorders, and the damage may occur without the operator being aware of the fact. This article contains recommendations to be followed when visual display unit (VDU) operators' eyesight is to be tested: workpost inspection, job description, roundup of technical data concerning the workpost, working conditions, complete eye examination. When inspecting the workpost the ophthalmologist should be accompanied by a member of the staff delegates' council. The author stresses the importance of eliminating reflected light by correct placing of the VDU, shielding the VDU from ambient light, or placing a screen behind the operator. Other factors to be taken into consideration include inclination of the CRT screen in relation to the natural angle of vision, ambient lighting and legibility. The characters of the text displayed on the screen should be clearly legible, not too small and pale or soft yellow in colour.
Five physically active young healthy workers, aged 2 0 - 2 4 years, were subjected to runs on a treadmill for 8 h at different relative loads (RLs) ie the percentage of maximum aerobic power (Vo max), viz 20, 30, 40, 50, 60 and 70~o, in comfortable laboratory conditions to determine the acceptable workload (AWL) for sustained physical activity. The findings have indicated that 35% RL could perhaps be reasonably considered as the AWL. The energy expenditure and the corresponding heart rate at this level of work would be around 18 kJ/min (gross) and 110 beats/min respectively. 11.3.10 (78140) Wolf, K.H. Practical implications of ergonomic and technical safety improvements in shunting (Ergonomische und Sicherheit stechnische Verbesserungen im Rangierdienst aus Betriblicher Sicht). (In German.) Heft 22 Moderne
Unfaliverhutung, Vulkan- Verlag, Dr W. Classen, Haus der Technik, Essen, Germany, 1978, pp 8 9 - 9 5 ; abstr in CIS Abstracts (CIS 79-831).
An analytical review of transport relations and the structure of operations in railway shunting is followed by a study of the energy expenditure and heart rate of a shunter during operations of various degrees of difficulty. The level of risk depends on communications 11.3.8 (78084) within the shunting team and the Johansson, C.R. number of workers per shunt unit Psychological job hazards - more (locomotive + waggons). The most common than you think. Working Environment - Arbetsmil]o International, dangerous operations during shunting are 'climbing into and out of a vehicle', 1979, pp 2 3 - 2 6 . 'coupling' and 'shoe braking'. A shunter Psychologically demanding jobs are can comfortably work alone on a shunt as common as physically strenuous ones. unit, and preference is therefore given
Applied Ergonomics
September1980
175
Kopala, C.J. The use of colour-coded symbols in a highly dense situation display. In:
Compass for Technology, Proceedings of the 23rd Annual Meeting of the Human Factors Society, Boston, Massachusetts, Oct 2 9 - N o v 1 1979, Edited by C.K. Bensel, pp 3 9 7 - 4 0 1 . The effectiveness of redundant colour-coding for displays used by highly-loaded operators performing a series of complex tasks has never been clearly demonstrated. Pilot flight performance and threat recognition performance using two coding conditions for a threat display were compared in a simulated mission. One coding condition consisted of shapecoded symbols, the other of symbols that were both colour- and shape-coded. Redundant colour-coding was found to significantly reduce both response time and error rate.
Factors affecting perceptual-motor performance 11.3.6 (78077)
Smith, W.K. A review of literature relating to visual fatigue. In: Compass for Technology,
Proceedings of the 23rd A nnual Meeting of the Human Factors Society, Boston Massachusetts, Oct 2 9 - N o v 1 1979, Edited by C.K. Bensel, pp 3 6 2 366.
The design of workstations with visual displays has become the subject of considerable interest and concern during the past few years. One area of concern relates to the assumption that long term viewing of such displays at close focal distances may contribute to visual fatigue. A second is the effect on the human visual system of the frequent changes in surface illumination associated with display units used in combination with hard copy documents. As a consequence of these and other concerns, the popular press has published articles that have aroused the interest of various scientific organisations regarding the subject of these effects. This paper discusses a review of some of the literature regarding a limited aspect of this issue, namely the accommodation and pupillary systems as they relate to long term viewing of visual display units.
Blue-collar workers in Sweden relate psychological strain chiefly to physical factors in the working environment. White-collar employees more frequently mention psycho-social reasons. But mental stress factors also contribute to their enjoyment of their jobs. Curt R. Johansson, whose division in the Psychology Department of Lund University specialises in labour-related studies, summarises a number of investigations on the psychological and physical hazards in Sweden's working environment.
Physiology, anthropometry and biomechanics 11.3.9 (78138)
Saha, P.N.,
et
al
An acceptable workload for Indian workers. Ergonomics, 1979, 22.9, 1059-1071.
11.3.7 (78079)
Conrads, H. Yon. An ophthalmologist's evaluation of work at visual display units (Die Beurteilung der Arbeit an Datensichtgeraten aus Augenarztlicher Sicht). (In German.) Zentralblatt fur Arbeits-
medizin, Arbeitsschutz und Prophylaxe, Sep 1978, 28.9, 2 5 6 - 2 5 8 ; abstr in:
CIS Abstracts (CIS 79-1007). Work at CRT display terminals may cause organic and functional eye disorders, and the damage may occur without the operator being aware of the fact. This article contains recommendations to be followed when visual display unit (VDU) operators' eyesight is to be tested: workpost inspection, job description, roundup of technical data concerning the workpost, working conditions, complete eye examination. When inspecting the workpost the ophthalmologist should be accompanied by a member of the staff delegates' council. The author stresses the importance of eliminating reflected light by correct placing of the VDU, shielding the VDU from ambient light, or placing a screen behind the operator. Other factors to be taken into consideration include inclination of the CRT screen in relation to the natural angle of vision, ambient lighting and legibility. The characters of the text displayed on the screen should be clearly legible, not too small and pale or soft yellow in colour.
Five physically active young healthy workers, aged 2 0 - 2 4 years, were subjected to runs on a treadmill for 8 h at different relative loads (RLs) ie the percentage of maximum aerobic power (Vo max), viz 20, 30, 40, 50, 60 and 70~o, in comfortable laboratory conditions to determine the acceptable workload (AWL) for sustained physical activity. The findings have indicated that 35% RL could perhaps be reasonably considered as the AWL. The energy expenditure and the corresponding heart rate at this level of work would be around 18 kJ/min (gross) and 110 beats/min respectively. 11.3.10 (78140) Wolf, K.H. Practical implications of ergonomic and technical safety improvements in shunting (Ergonomische und Sicherheit stechnische Verbesserungen im Rangierdienst aus Betriblicher Sicht). (In German.) Heft 22 Moderne
Unfaliverhutung, Vulkan- Verlag, Dr W. Classen, Haus der Technik, Essen, Germany, 1978, pp 8 9 - 9 5 ; abstr in CIS Abstracts (CIS 79-831).
An analytical review of transport relations and the structure of operations in railway shunting is followed by a study of the energy expenditure and heart rate of a shunter during operations of various degrees of difficulty. The level of risk depends on communications 11.3.8 (78084) within the shunting team and the Johansson, C.R. number of workers per shunt unit Psychological job hazards - more (locomotive + waggons). The most common than you think. Working Environment - Arbetsmil]o International, dangerous operations during shunting are 'climbing into and out of a vehicle', 1979, pp 2 3 - 2 6 . 'coupling' and 'shoe braking'. A shunter Psychologically demanding jobs are can comfortably work alone on a shunt as common as physically strenuous ones. unit, and preference is therefore given
Applied Ergonomics
September1980
175