used by the photo interpreter must permit him to extract the in- 
formation both efficiently and accurately." 
In discussing the second of the above-listed considerations, 
this reference made the following rather optimistic statement 
which perhaps needs to be re-evaluated in light of developments 
since it was written, nearly 20 years ago: 
"Until recently there was a tendency to assume that one 
person was as well suited to photo interpretation work 
as another. Consequently, the selection process revolved 
primarily around considerations as to the relative 
availibility of two or more people to handle an additional 
task, in this instance aerial photographic interpretation. 
However, we are gradually coming to realize that the 
differences between a good photo interpreter and a poor 
one can be largely explained on the basis of (1) differences 
in visual acuity (2) differences in mental acuity, and 
(3) differences in general attitude toward the photo 
interpretation task." 
That article then traced seeming progress in each these three 
areas, cited a very successful 11-phase aptitude test for 
photograph users and announced the recent finding of "highly 
significant correlations between the candidate's photo inter- 
pretation abilities and his abilities in general mathematics, 
mechanical principles, and arithmetic reasoning," and speculated 
on the probable importance of "capacity for learning, adaptability, 
and powers of judgement." It also included a sample test that 
might be applied for determining a candidate's attitude toward 
the photo interpretation task, and discussed recent improvements 
in photo interpretation training methods, materials, and equipment. 
In retrospect, we can see that progress has been much slower in 
the 20 years since, particularly in implementing the various 
findings and concepts referred to above, than had been antici- 
pated. On the other hand, a rather cautious understatement was 
made in that reference with respect to the future use of com- 
puters. The statement simply cited their increased use by photo 
interpreters "to make multiple correlation analyses, derive 
multiple regression equations, and determine the statistical 
reliability of various sizes of samples and methods of sampling." 
Finally, that article of 20 years ago, in discussing recent 
improvements in the methods and techniques of photo interpretation 
cited (a) methods for orienting a stereo model beneath the 
stereoscope; (b) methods for handling a large stack of photos 
in an orderly manner during the photo interpretation process; 
and (c) methods for avoiding duplication or omission in the 
interpretation of areas common to two or more overlapping photo- 
graphs. In retrospect we perceive that no significant break- 
throughs in any of these mundane methods, common though they are 
to virtually all kinds of photo interpretation, have been made 
in the interim. 
In looking to the future that article was quite correct in pre- 
dicting that "for the first time, extremely small scale photo- 
graphy taken with a photo reconnaissance satellite from an 
      
  
     
     
     
   
  
  
   
   
  
  
  
  
  
  
  
  
  
     
   
  
  
  
   
   
   
    
   
  
  
  
  
  
  
  
    
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