The city is an object of complex representation which implies a built notion of a place full of meanings, as well as a group of graphic and cartographic images which we use in our way-findings. As the city develops, its mental and social representations are seized to multiples changes. However, environmental cognition research so far seems to have focused in a predominantly static view of urban territories, neglecting a more dynamic and temporal perspective upon what Lynch (1960) called “the image of the city”. In this frame, by means of reworking the validity of the cognitive mapping technique, the paper aims to analyze the social representations of the urban transformations of the city in a longitudinal perspective. Lynch’s work introduced the term ‘imageability’ to explain the quality of an urban setting which gives an observer a strong and vivid image. This image contains very distinct parts allowing its residents to instantly recognize it: paths, edges, districts, nodes and landmarks. Several studies on cognitive maps of cities confirm the existence of these categories (Appleyard, 1969; Francescato and Mebane, 1973; Aragonés and Arredondo, 1985). These were applied in our study in order to grasp the correspondence between urban physical changes and people’s psychological composition of them, framed in a metropolis-driven urban growth trend. The sample included 510 university students between 1988 and 2007. Subjects were asked to sketch the map of Barcelona including all the elements of the city that cAme to their minds. The analysis consisted of quantitative data: number and variety of elements, typology of spatial structure, common distortions, represented and not-represented places, special features, etc. Results show similarities and differences among the sketch maps, mainly old and new features of the urban texture and changes in the cognitive style of representation, linked to a change of urban scale.