Milgram, S. Environmental Psychology: People and Their Physical Settings, 2nd ed. Holt, Rinehart and Winston, New York, USA, 1976, ch. Psychological Maps of Paris, pp. 104–124.
In this paper, Milgram describe a psychological study he conducted with habitants of Paris, to study their mental representation of their city. (1) The first principle he explain is that reality and image are imperfectly linked. The main problem he encountered is how to render this image observable.
Many of the concepts people have about cities are nonverbal, spatial ideas. They are not easily translated into words.
(2) The second principle is that one can readily fuse private and public aspects of life through the network of streets and landmarks.
(3) The third principle is that some properties of the mentalised places may be changed (e.g, they deviate from their true spatial coordinates but they do preserve a topological sequence.
Several cognitive processes take place on the mental map: selectivity; emphasis; distortion; projections of lifestyle. Neither the city nor the map are just agglomeration of objects: they are structures. It is a feature of the structure that displacement of one element is not an isolated event. Rather has consequences for the other elements with which is linked.
In addition to these points, a city is a social fact. Therefore the perception of the city is a social fact, and as such it need to be studied in its collective and in its individual aspects.
Milgram analysed a certain number of mental maps and noticed the emergence of common elements. The boundaries and the rivers (Lynch’s LIMIT), the landmarks of Paris, the links (Lynch’s PATHS).
Milgram’s analysis extended on using several different techniques such as “the last walk”, “the meeting point”, “the free associations”. Using these systems he produced several different visual image of the city that unveiled interesting phenomena, such as that whereas the psychological center of Chigago or any big american city is constantly changing position, the psychological center of Paris is always the same rooted on the cultural simbols of France.