"Contemporary official or "designed" architecture generally creates institution nary buildings and environments. Contemporary "spontaneous" or self help archi tecture (harriadas, bidonvilles, etc) creates non-institutionnary or more precisely anti-institutionnery environments. Their mode of production differs radically: In the first case is hetero-geners ted , in the second it is self-generated. Their perceptual organization also differs: In the first case it is more or less one-dimensional, in the second it is multi-dimensional. An effort to correlate these characteristics is made. A discussion on the different ways of appropriation and the "degree of privacy" of space follows."