Chapter 2 

 PRINTED MATERIALS, MAPS, AND CHARTS 



MASON N. CROOK 

 Tufts College 



Introduction 



The use of maps, charts, and printed ma- 

 terials enhsts a variety of sensory, percep- 

 tual, and motor functions on the part of the 

 user. We are here concerned with the prob- 

 lem how to arrange conditions most advan- 

 tageously for the performance of these func- 

 tions. Solutions must often be a compromise 

 among capacities of the organism, charac- 

 teristics of the work situation, and tech- 

 nological limitations in the production of 

 materia Is. Certain aspects of performance, 

 such as the increased difficulty of reading 

 maps under colored Hght, can be predicted 

 from a general knowledge of the visual re- 

 ceptor mechanism as set forth in Chapter 1. 

 Most visual tasks involving the interpreta- 

 tion of symbols, however, are not capable of 

 full theoretical analysis and must be ap- 

 proached empirically. Ordinary reading typi- 

 fies this state of affairs and also illustrates 

 many of the problems, particularly of 

 methodology and interpretation, encount- 

 ered in the investigation of other visual 

 tasks. Therefore, a brief review of some 

 representative samples of the extensive work 

 on this topic will provide us with a helpful 

 frame of reference. Much of the material 

 can be treated in relation to three variables, 

 typography, illumination, and fatigue. 



Reading Printed Text 



We can distinguish two general kinds of 

 experimental situations: (1) those in which 

 subjects are required to approximate normal 

 reading of good quality book type, in rela- 

 tion to which certain functions are measured, 

 and (2) those in which some form of thres- 

 hold determination is made. Among the 

 latter are determinations of the distance at 



which type can be read, of the effects of im- 

 pairment of focus of a projected image, of 

 discrimination in brief exposures, of reading 

 limits ^ath the Luckiesh-Moss "visibifity"' 

 meter, and of acuity by classical methods. 

 The significance of such measures for normal 

 reading is at best inferential, and different 

 methods have in some cases given clearly 

 different results or have been open to dif- 

 ferent interpretations. (See, for example. 

 Chapter 1 on visual acuity measures.) We 

 shall, therefore, confine ourselves in this sec- 

 tion to the more direct investigations of nor- 

 mal reading. Tests of legibihty at a dis- 

 tance, which are relevant to the reading of 

 wall placards, will be separately discussed. 

 Even within the area of normal reading 

 studies, a conflict exists over ways of measur- 

 ing results. Measures of reading speed by 

 means of standardized tests are held by 

 Tinker to be a satisfactory criterion. He is 

 opposed by Luckiesh and Moss, who claim 

 (1) that reading speed is a relatively insen- 

 sitive measure, and (2) that it is a measure 

 of output only, and takes no account of the 

 cost to the organism of doing the work of 

 reading. Proceeding on the assumption 

 that some involuntary behavior concomitant 

 with reading would be hkely to indicate 

 the effort expended, they have investigated 

 a number of such concomitants, among them 

 muscle tension, bhnk rate, and heart rate. 

 Of these they have settled on bhnk rate as 

 the most usable (30, pp. 1 15-12 1).^ In a 



1 When research programs have been sum- 

 marized in book form, the book references only 

 will be cited. References to selected experi- 

 mental articles not covered in such summaries, 

 and to the more relevant surveys and reviews, will 

 be given. Much of the material on typographical 



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