This thesis aims at investigating the mapping between the sentential content and the content presented in graphs in a multimodal comprehension process. We assume an experimental approach, based on Cognitive Pyschology and Psycholinguistics methodological and theoretical contributions as well as literacy and multimodality studies. Two proposals concerning the integration between linguistic and visual information are considered: one linked to Jackendoff s (1996) representational modularity hypothesis, in which, the idea of interface modules, of hybrid nature, is defended; and an alternative one according to which linguistic and visual processing could generate propositional/abstract representations which could be integrated into a conceptual interface. We tried to check (i) if top-down aspects such as prior knowledge can affect this integration and (ii) in what extent linguistic information may bring expectations about the information expressed in the graph. Sentence-picture comparison experiments were conducted with line and columns graphs using the pyscope software, and another one concerning line graphs with eye tracking technique. Top-down effects were not found in columns graphs experiment. However, significant effects related to response time associated with other aspects such as graph accuracy, lexical expression used in order to compare graph elements (larger x smaller, for example) and the number of elements in the sentence that must be found in the graph. In both experiments with line graphs, the independent variables were (i) congruency (congruent/incongruent line in relation to the verb - line up or down vs verb increase) and (ii) accuracy of the graph in order to express the content of the sentence, manipulated with changes in the line and time information order (ascendant/descendent) in x axis. In psyscope experiment, there was no difficulty in judging the sentence-picture compatibility when congruency and correction were not different. Concerning the response time, there was effect of congruency and correction, with shorter times associated, respectively, to the conditions in which line was congruent to the verb and correct graph. There was also effect of interaction. In eye tracking experiment, accuracy rates, number of fixations, total fixation duration and the scanpath in areas of interest were analysed. In relation to accuracy rates, similar to psyscope experiment, more difficulty in processing was associated to incongruent/incorrect condition, in which there is a break in the expectation related to the line position (vs.verb) and the common organization of the elements displayed in x axis. Concerning eye movements, in the graph area, number of fixations and total fixation duration were higher in correct conditions; in the sentence area, these results were opposite. Analyzing the scanpath, data suggest that linguistic information is accessed first, guiding the graph reading. To conclude, it s possible to state that the cost of integration is determined by compatibility (or not) between the propositions from both linguistic and visual modules.