The Operator’s Abilities and Limitations

Toni Ivergard and Brian Hunt

CONTENTS

10.1 Introduction…………………………………………………………………………………………….. 265

10.2 Sense Organs and Perception…………………………………………………………………… 266

10.2.1 Sight and Vision………………………………………………………………………… 267

10.2.2 Colour Vision……………………………………………………………………………. 270

10.2.3 Central Vision…………………………………………………………………………… 271

10.2.4 Focusing of Colours on the Lens………………………………………………. 272

10.2.5 Colour Blindness………………………………………………………………………. 273

10.2.6 Meaning and Perception…………………………………………………………… 274

10.2.7 The Effects of Aging…………………………………………………………………. 274

10.2.8 Hearing……………………………………………………………………………………… 275

10.2.9 Other Sense Organs…………………………………………………………………… 276

10.3 Job Skills………………………………………………………………………………………………….. 276

10.4 Perception and Simple Decisions…………………………………………………………….. 278

10.4.1 Discrimination of Signals…………………………………………………………… 278

10.4.2 Simple Decisions……………………………………………………………………….. 279

10.4.3 Changes with Age……………………………………………………………………… 282

10.5 Overloading and Underloading……………………………………………………………….. 284

10.5.1 Fatigue and Alertness………………………………………………………………… 284

10.5.2 Underloading…………………………………………………………………………….. 286

10.6 Motor Functions………………………………………………………………………………………. 288

References and Further Reading……………………………………………………………………….. 289

10.1 INTRODUCTION

The abilities and limitations of the operator in control room work are discussed in more detail in this chapter. We aim to give concrete data that can be of use in the design of control rooms. Much of the background discussion, motivation, and other important aspects is omitted in order to bring about a fully comprehensive solu­tion, as it is not possible to summarise these in a handbook of this type. For more detailed information, the reader should refer to the specialist psychological or socio­psychological literature, or consult ergonomic or psychology experts in the field (for example, Stevens, 1975; Hamilton, 1983; Salvendy, 1986).

The description of human psychology and physiology is also highly simplified. Models of the type given in this book have a certain justification in the planning of control rooms and the like. However, they must be used with care. The discussion is based on the model shown in Figure 2.17. The operator’s sense organs and percep­tion are considered first and then the decision and memory functions are examined. In conjunction with these, we give examples of decision-making speed, different types of decisions, and the problems associated with over – and underloading. Some information on the human motor system and ability to carry out various manoeuvr­ing and control movements is given in the later part of this chapter. Chapters 3, 4, and 5 provide examples on the design of information and control devices.