• 1940s - watching movies in the theater in my Scottish village
• 1960-1965 - attending graduate school in Psychology at Cornell University
• 1975 - party in California
• 1989 - conference on three-dimensional media technology in Montreal

• FLASHBACK Growing up in Lochwinnoch, a small village in Scotland, I used to be very impressed by Johnny Manders, who ran the local cinema single-handed. Johnny would stand out in the street as a barker. Roll up, roll up, only a few seats left! When he lured in some customers, he would interrupt his spiel to be ticket collector and usher. After capturing a large enough audience, he would become the film projectionist. The movie would be interrupted halfway through while he sold popcorn and soft drinks. (It always seemed to me as a child to stop at an exciting part but now I realize that there was only one projector and it was necessary to change reels.) After the audience had bought enough to bribe him to get back to being projectionist, the movie would continue.

• FAST FORWARD Twenty-five years later, I was attended a two-day graduation party for a friend. I was taking many photographs to build a souvenir album. I ran out of color film, borrowed some black-and-white film, and continue taking pictures with more abandon, since the film is cheaper (Twenty-five years later, I am still Scottish!). I ran out of black-and-white film, but continue with even more abandon with the empty camera. (It is now the afternoon of the second day!) Since there is not any record of the shots, I decide to abandon the camera and take shots simply by blinking. Suddenly I realized that there was little point in taking stills when I had a continuous movie going and - blinking no more - I sat back to enjoy the movie.
• REWIND In retrospect, then, running a one-man cinema is not so impressive. Every one of us is running a magnificent mobile movie studio of a mind, with wide-angle screen, stereophonic sound, Technicolor, and cast of thousands (but only one hero/heroine), in which we are producer, director, script-writer, camera person, sound engineer, stage manager and crew. This movie studio also doubles as a movie theater, in which we can simultaneously watch the show. (We are also the movie critic who reviews the performance next morning!) The only limitation is that, in the movie theater of the mind, there is only one seat. In order to show your home movies to other people, you have to learn to write, to speak, to play music, to make films. Some of us earn reputations for being good at showing our home movies, using a particular medium, and are thus recognized as artists. However, we are all artists in the sense that we all try, by some means or another, to invite other people in to see our home movies.
• FAST FORWARD AGAIN I spent four years with J. J. Gibson while a graduate student at Cornell University between 1961 and 1965 and never understood what he was talking about. Yet he was one of the most important influences in my life. He was very excited about something (whatever it was) and I wanted to share this excitement. Ten years later, at that California party, I began to understand what he had been talking about.

Our visual world is built out of this "Mind Movie" which we are running in the magnificent mobile mind studio and viewing in the mind theater. "Mobile" is a important feature of this studio. Now I understand why J. J. used to chuckle when the tachistoscope arrived in the department and every graduate student suddenly realized that their research required this new tool. It enabled us to fix the subject in a chin-rest staring down a tunnel where we could systematically and accurately present stimuli and measure precisely their response. A person discovers the real world by moving around in it - moving the body with respect to the environment, the head with respect to the body and the eyes with respect to the head. By preventing the subject from moving the body, the head and the eyes, we were able to conduct a very controlled experiment but we could not learn anything about how s/he learned about the real world. It was street-lamp research, named in honor of the drunk who dropped his key while trying to open his door and went to look for it under the street-lamp because the light was better there. The light may be better there but it is not where the key is.

J. J's wife, Eleanor Gibson, conducted a study with Richard Walk, in which the subjects were allowed to move. Young organisms were placed on a platform with a shallow end at one side and a deep end at the other side (it only looked deep hence the experiment was called the visual cliff) [GIBSON E & WALK R]. Subjects, whether young children or kittens or puppies, invariably walked off the shallow end (even when mothers treacherously called the young children from the deep end). Gibson and Walk concluded that young organisms have depth perception. Critics replied that they had demonstrated only that they had depth perception when they could walk. The experimenters argued that that is when they need depth perception and nature kindly supplies it by providing the necessary information as they learn to walk.

The visual field (J. J's name for the single frame in this movie) could be very complex, if it contained many people and things, to which the person has multiple cognitive and emotional associations. Some German researchers simplified the visual field by building a Ganzfeld (German for whole field) consisting of a six-foot translucent sphere. A subject sitting in the center of this sphere would have the total retina equally stimulated. Julien Hochberg, another perception theorist at Cornell University, with typical Yankee ingenuity, built the pocket Ganzfeld by cutting a ping-pong ball in half and placing the two halves over the eyes of the subject. The first step towards making the Ganzfeld more complex was to draw a dot on the sphere or ping-pong ball. The subject recognized this as a figure on a ground. This figure-ground relationship is the basic perceptual experience. When a blind patient has cataracts removed and sees for the first time, this is what he sees. He does not immediately reach up after the bandages are removed and embrace his fiancee, as in Hollywood movies. He could not tell his fiancee from the doctor or from the bedside-table, but he could tell that there is a figure against a ground.

• FAST FORWARD AGAIN In 1989, Christine Davet, Hal Thwaites, and I organized a conference on Three-dimensional Media Technology. In an opening speech, I said:
  Since this is a conference on the third dimension, we have decided to invite only three-dimensional speakers, hold it (as you can see) in a three-dimensional room, serve drinks in three-dimensional glasses and food on three-dimensional plates.

A camera is simply a light-tight box with a hole at the front and a light-sensitive surface at the back. You point the camera at an object, open the hole, and an image of the object appears on the surface. Each innovation is simply a device to improve the resolution and permanence of the image. Medieval artists were familiar with the camera obscurata (pinhole camera) as a device for providing an initial outline for a painting. Indeed, Lynn Picknett and Clive Prince have argued that the first photograph was the Turin Shroud taken in 1492 by Leonardo da Vinci [PICKNETT & PRINCE]. Pope Innocent V111 commissioned the Shroud (ostensibly the one that wrapped the body of Jesus Christ after he was taken down from the cross) as a publicity exercise. Leonardo used a composite of his own face and the body of a genuinely crucified man, a pinhole camera and a chemical sensitive to light to create the world's first photograph.⁴⁰

There are a number of ways of adding to the accuracy of our movie of the mind. One technology is high-definition television (HDTV), which provides improved picture resolution. With HDTV the aspect ratio of the TV screen is closer to that of the eye than with conventional television. The IMAX film format comes even closer to our mind movie by removing the artificial frame around the image. The IMAX screen is so large that it fills most of our visual field. The OMNIMAX screen, even bigger and curved at the edges, does this even more effectively. Though it does not remove the border, the IMAX/OMNIMAX format allows it to be replaced by the more natural oval border of the eye as it takes a snapshot of the world.⁴¹

A big step towards simulation of the mind movie was taken when we learned to capture motion on film. Edward James Muggeridge (1830 - 1904) was born in Kingston upon Thames, Surrey in 1830 and died as Eadweard Muybridge in Kingston upon Thames, Surrey in 1904. (He had adopted the latter which he presumed to be the Anglo-Saxon form of his name.) Unlike Darwin, however, he had spent most of his intervening life outside his English village. He traveled extensively in North and Central America pursuing his career as a photographer.

His most famous photographs were commissioned by Leland Stanford (after whom Stanford University is named) to help him win a bet. Stanford had bet $25,000 that at some moment in its gait all four feet of his famous trotting horse Occident were off the ground at the same time. Muybridge lined up a battery of 24 cameras, equipped with a shutter he had developed which gave an exposure of 2/1000th of a second. As the horse trotted past, it broke threads which triggered the cameras and made a series of 24 exposures. On some of those exposures, all four feet were off the ground, and Stanford won his bet.

Muybridge printed those 24 photographs on a circular glass disc, which projected them in rapid succession on to a screen as it was spun, creating the illusion of movement. This zoopraxiscope, which created a sensation at the Columbian Exposition in Chicago in 1893, was a precursor of the film projector. He had stumbled upon the perceptual phenomenon of persistence of vision or phi phenomenon. Since an image projected on the eye persists, an appropriate series of images projected at a certain rate will create the illusion of motion. This rate, called the critical flicker frequency (CFF), is about 24 frames per second. This primitive prototype of the film projector earned him the title of Father of the Motion Picture. Muybridge devoted the rest of his life, before returning to his village to retire, to compiling portfolios of photographs illustrating the movement of animals including us. Those portfolios have served as a valuable guide for scientists and artists during the intervening century [MUYBRIDGE].

The various media could be classified in terms of spatial dimensions. Thus, print and radio would be one-dimensional, photography and painting would be two-dimensional, sculpture and holography would be three-dimensional, dance and theater would be four-dimensional since they add the fourth dimension of time. Film and television would be three-dimensional, the third dimension being that of time rather than depth. This next step in the progression toward a more accurate simulation of the mind movie for film would therefore involve filling in this "missing" depth dimension.

Progression is, of course, not necessarily progress. Many will resist this next step, just as many in the past resisted the introduction of movies, talkies, and color. Many people certainly resist the retroactive introduction of color to films originally shot in black-and-white. Whatever the arguments mustered by critics of colourization (and there are many good ones), the idea that black and white is somehow more natural, is totally unfounded. There is nothing natural about black-and-white unless you are totally colour-blind.⁴² The same argument applies to two-dimensional images, which are as artificial as black-and-white images. 2-D representations of our 3-D world are cultural artifacts. This is demonstrated by anthropological studies in which people, who have no previous experience of photographs and paintings, have trouble interpreting them.

40   Leonardo has a reputation as a practical joker. Some have argued that his famous Mona Lisa is a self-portrait [HONORE]. X-rays reveal a beard under her cheeks and a computer aligned her features with a portrait of da Vinci. Her enigmatic smile is the result of a male smile on a female face.

41   Despite all those innovations, the resolution is not as good as our eyes. Julien Winfield, one of my students who helped me with the edutainment section of the CD-ROM to accompany the movie Rob Roy, told me the following story. He was working long hours staring at a screen in a beach house in Santa Cruz. As his attention drifted to the view of the Santa Cruz beach in the picture window behind his screen, he was astonished at the great resolution on that "screen". When he started however to try to get his cursor on some passing cloud to edit the image, he realized that it was time to quit.