Essential McLuhan 126 immediately subject to the impact or intrusion of any mechanically extended sense. That is, writing affects speech directly, not only its 6 accidence and syntax but also its enunciation and social uses. Why non-literate societies cannot see films or photos without much training. Since the present object is to elucidate the effective causality of phonetic writing in setting up new kinds of perception, let us turn to a paper7 by Professor John Wilson of the African Institute of London University. For literate societies it is not easy to grasp why non-literates cannot see in three dimensions or perspective. We assume that this is normal vision and that no training is needed to view photos or films. 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 ihere 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 righthand, bottom segment of the frame. This was all that had been seen. The other things he had hoped they would pick up from the film they had not picked up at all, and they had picked up something which we didn’t k now was in the film until we inspected it minutely. Why? We developed all sorts of theories. Perhaps it was the sudden movement of the chicken. Everything else was done in slow technique— people going forward slowly picking up the tin, demonstrating and all the rest of it, and the bird was apparently the one bit of reality for them. For them there was another theory that the fowl had religious significance, which we rather dismissed. Question: Could you describe in more detail the scene in the film? Wilson: Yes, there was very slow movement of a sanitary laborer coming along and seeing a tin with water in it, picking the tin up and very carefully