Wilson’s experiences arose from trying to use film in teaching 
natives to read:

     The next bit of evidence was very, very interesting. This 
     man—the sanitary inspector—made a moving picture, in 
     very slow time, very slow technique, of what would be 
     required of the ordinary household in a primitive African 
     village in getting rid of standing water—draining pools, 
     picking up all empty tins and putting them away, and so 
     forth. We showed this film to an audience and asked 
     them what they had seen, and they said they had seen a 
     chicken, a fowl, and we didn’t know that there was a fowl 
     in it! So we very carefully scanned the frames one by one 
     for this fowl, and, sure enough, for about a second, a fowl 
     went over the corner of the frame. Someone had 
     frightened the fowl and it had taken flight, through the