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Evaluation of conventional, serial and chord keyboard options for mail encoding
serial visual presentation (RSVP) technique. In RSVP the text is divided into small units of one or a few words that are presented successively for brief durations to a common location on a screen. Text presented in this way can be read rapidly and with good comprehension, while the need for eye movements is eliminated. The data from several studies indicate that RSVP can actually improve the comprehension abilities of less-skilled readers. The present paper explores the reasons for this apparent advantage of RSVP for some readers, and proposes ways in which the method might be applied in instructional settings. 20.1.21 (109320)
Millar, S. Perceptual and task factors in fluent braille. Perception, 1987, 1 6 . 4 , 5 2 1 536. Hypotheses that fluent braille depends (i) on coding letters by global outline shape for all task and speed levels, or (ii) on lateral dot-gap density scanning in fast reading for meaning were tested with three groups of fluent braillists who differed in reading speeds. In Experiment 1, 90°-rotated (near to far) texts under vertical and horizontal finger orientation were used. Hypothesis (i) was not supported. Finger orientation interacted significantly with Speed and Task. Vertical finger orientation, which disrupts lateral scanning, slowed reading for comprehension more than for for letter search, and differentially more for faster readers. Horizontal finger orientation, which instead disrupts the familiar finger-body relation, did not have differential effects. The findings support hypothesis (ii). In Experiment 2, normal texts and texts containing a degraded dot in some letters were used. These are felt in searching for individual letter patterns, but would disrupt lateral scanning'of expected dot-gap density patterns in reading for meaning. The results supported the predictions from hypothesis (ii), that degraded texts slow reading for meaning significantly more than for letter search, and more in the case of faster readers than for the slowest group. Findings were not consistent with hypothesis (i), which predicts that text degradation affects tasks equally, and affects the slowest rather than the faster readers. The results suggest that perceptual coding in reading differs with task demands and speed. 20.1.22 (109335)
Various surveys and compilations have led to the conclusion that 'human error' is a primary cause of most major accidents in aviation, power production and process control. This conclusion has led to a variety of efforts to reduce or possibly eliminate human error. While such efforts to reduce human error are important, they can, if taken to an extreme, be very short-sighted. A strategy that is more likely to be successful is one that tolerates the occurrence of errors, but avoids their consequences. Error tolerance can be achieved in three complementary ways: (1) feedback about current consequences, (2) feedback about future consequences, and (3) intelligent error monitoring. These approaches are complementary and can be viewed as providing multiple levels of support relative to the consequences of human error. This paper elaborates on each of these approaches and then suggests how they might be integrated in terms of a human error-tolerant interface for complex engineering systems. A conceptual design for such an interface is presented. The practical implications and limitations of implementing this design are also considered.
Display and control design 20.1.23 (109413)
Richardson, R.M.M., Telson, R.U., Koch, C.G., and Chrysler, S.T. Evaluation of conventional, serial and chord keyboard options for mail encoding. In: Rising to new heights with technology. Proc Human Factors Soc 31st Ann Meeting, New York City, 1 9 - 2 3 Oct 1987. Human Factors Soc, Santa Monica, Cal, Vol 2, 1987, pp 911-915. The motivation for the experiment was the integration of a work station display component and a suitable data entry device. Keying performance with three candidate keyboards was evaluated: (1) a one-handed con° ventional calculator keyboaid, (2) a two-handed 10-key serial keyboard, and (3) a two-handed 10-key chord keyboard. Subjects were trained to criteria on a numerical data entry task and subsequently tested for performance in encoding five-digit strings. Measures of encoding response time and encoding errors showed a substantial advantage in training time for the calculator keyboard and two-handed serial chord keyboard.
Rouse, W.B., and Morris, N.M. Conceptual design of a human error tolerant interface for complex engineering systems. A utomatica, 1987, 23.2, ~ 3 1 - 2 3 5 .
64
Applied Ergonomics
20.1.24 (109454)
Palmiter, S.L. and Elkerton, J. Evaluation metrics and a tool for control panel design. In: Rising to
March 1989
new heights with technology. Proc Human Factors Soc 31st Ann Meeting, New York City, 1 9 - 2 3 Oct 1987. Human Factors Soc, Santa Monica, Cal, Vol 2, 1987, pp 1 1 2 3 1127. In the use of control panels for the automotive industry, consistency and usability are of major importance. General qualitative guidelines exist for the designer, but there is currently a lack of quantitative human factors data for control panel designs. A state of the art design tool which provides the designer with ergonomics usability guidelines and structure is needed. As part of the current research, a computer-based tool which provides a quantitative analysis of the ergonomic quality of a control panel layout has been created. This tool is a tailored Auto-CAD program for the IBM PC which provides features to encourage consistency and structure in the design of control panel layouts. Extending the work by Tullis (1983) on alphanumeric display metrics, four graphical metrics for the overall and functional design levels are included as part of the design tool. These metrics are: (1) Overall density - ratio of free space to occupied space; (2) Local density - how closely placed the design entities are to each other; (3)"Layout complexity - position irregularity of functional areas; and (4) Display grouping - number of functions and number of controls and displays. In this effort, the design metrics and the design tool have been developed. 20.1.25 (109458)
Simpson, G.C., and Chan, W.L. The derivation of population stereotypes for mining machines and some reservations on the general applicability of published stereotypes. Ergonomics, 1988, 3 1 . 3 , 3 2 7 - 3 3 5 . Although population stereotypes have been investigated for almost 30 years, the existing literature is by no means unequivocal. Moreover, there are a number of control-response relationships (CRRs) found on modern mining equipment which have received no previous study. Such limitations make it extremely difficult to provide reliable ergonomics advice to designers. Twentyfour CRRs found commonly on mining machines were examined. Seventeen were found to have significant stereotypes which could be used as the basis for design recommendations. Several of the stereotypes derived were in conflict ,~ith recommendations already used both in the UK and elsewhere. This highlights the danger of the assumption, implicit in many sources, that stereotypes are universally applicable. In addition to the primary objective of providing reliable design recommend-
Millar, S. Perceptual and task factors in fluent braille. Perception, 1987, 1 6 . 4 , 5 2 1 536. Hypotheses that fluent braille depends (i) on coding letters by global outline shape for all task and speed levels, or (ii) on lateral dot-gap density scanning in fast reading for meaning were tested with three groups of fluent braillists who differed in reading speeds. In Experiment 1, 90°-rotated (near to far) texts under vertical and horizontal finger orientation were used. Hypothesis (i) was not supported. Finger orientation interacted significantly with Speed and Task. Vertical finger orientation, which disrupts lateral scanning, slowed reading for comprehension more than for for letter search, and differentially more for faster readers. Horizontal finger orientation, which instead disrupts the familiar finger-body relation, did not have differential effects. The findings support hypothesis (ii). In Experiment 2, normal texts and texts containing a degraded dot in some letters were used. These are felt in searching for individual letter patterns, but would disrupt lateral scanning'of expected dot-gap density patterns in reading for meaning. The results supported the predictions from hypothesis (ii), that degraded texts slow reading for meaning significantly more than for letter search, and more in the case of faster readers than for the slowest group. Findings were not consistent with hypothesis (i), which predicts that text degradation affects tasks equally, and affects the slowest rather than the faster readers. The results suggest that perceptual coding in reading differs with task demands and speed. 20.1.22 (109335)
Various surveys and compilations have led to the conclusion that 'human error' is a primary cause of most major accidents in aviation, power production and process control. This conclusion has led to a variety of efforts to reduce or possibly eliminate human error. While such efforts to reduce human error are important, they can, if taken to an extreme, be very short-sighted. A strategy that is more likely to be successful is one that tolerates the occurrence of errors, but avoids their consequences. Error tolerance can be achieved in three complementary ways: (1) feedback about current consequences, (2) feedback about future consequences, and (3) intelligent error monitoring. These approaches are complementary and can be viewed as providing multiple levels of support relative to the consequences of human error. This paper elaborates on each of these approaches and then suggests how they might be integrated in terms of a human error-tolerant interface for complex engineering systems. A conceptual design for such an interface is presented. The practical implications and limitations of implementing this design are also considered.
Display and control design 20.1.23 (109413)
Richardson, R.M.M., Telson, R.U., Koch, C.G., and Chrysler, S.T. Evaluation of conventional, serial and chord keyboard options for mail encoding. In: Rising to new heights with technology. Proc Human Factors Soc 31st Ann Meeting, New York City, 1 9 - 2 3 Oct 1987. Human Factors Soc, Santa Monica, Cal, Vol 2, 1987, pp 911-915. The motivation for the experiment was the integration of a work station display component and a suitable data entry device. Keying performance with three candidate keyboards was evaluated: (1) a one-handed con° ventional calculator keyboaid, (2) a two-handed 10-key serial keyboard, and (3) a two-handed 10-key chord keyboard. Subjects were trained to criteria on a numerical data entry task and subsequently tested for performance in encoding five-digit strings. Measures of encoding response time and encoding errors showed a substantial advantage in training time for the calculator keyboard and two-handed serial chord keyboard.
Rouse, W.B., and Morris, N.M. Conceptual design of a human error tolerant interface for complex engineering systems. A utomatica, 1987, 23.2, ~ 3 1 - 2 3 5 .
64
Applied Ergonomics
20.1.24 (109454)
Palmiter, S.L. and Elkerton, J. Evaluation metrics and a tool for control panel design. In: Rising to
March 1989
new heights with technology. Proc Human Factors Soc 31st Ann Meeting, New York City, 1 9 - 2 3 Oct 1987. Human Factors Soc, Santa Monica, Cal, Vol 2, 1987, pp 1 1 2 3 1127. In the use of control panels for the automotive industry, consistency and usability are of major importance. General qualitative guidelines exist for the designer, but there is currently a lack of quantitative human factors data for control panel designs. A state of the art design tool which provides the designer with ergonomics usability guidelines and structure is needed. As part of the current research, a computer-based tool which provides a quantitative analysis of the ergonomic quality of a control panel layout has been created. This tool is a tailored Auto-CAD program for the IBM PC which provides features to encourage consistency and structure in the design of control panel layouts. Extending the work by Tullis (1983) on alphanumeric display metrics, four graphical metrics for the overall and functional design levels are included as part of the design tool. These metrics are: (1) Overall density - ratio of free space to occupied space; (2) Local density - how closely placed the design entities are to each other; (3)"Layout complexity - position irregularity of functional areas; and (4) Display grouping - number of functions and number of controls and displays. In this effort, the design metrics and the design tool have been developed. 20.1.25 (109458)
Simpson, G.C., and Chan, W.L. The derivation of population stereotypes for mining machines and some reservations on the general applicability of published stereotypes. Ergonomics, 1988, 3 1 . 3 , 3 2 7 - 3 3 5 . Although population stereotypes have been investigated for almost 30 years, the existing literature is by no means unequivocal. Moreover, there are a number of control-response relationships (CRRs) found on modern mining equipment which have received no previous study. Such limitations make it extremely difficult to provide reliable ergonomics advice to designers. Twentyfour CRRs found commonly on mining machines were examined. Seventeen were found to have significant stereotypes which could be used as the basis for design recommendations. Several of the stereotypes derived were in conflict ,~ith recommendations already used both in the UK and elsewhere. This highlights the danger of the assumption, implicit in many sources, that stereotypes are universally applicable. In addition to the primary objective of providing reliable design recommend-