The aim of the study is to identify the differences between the cognitive processes underlying different map-reading tasks. An eye-tracking study was designed based on our previous research. We hypothesized that significant differences may occur when utilizing two different methods of presenting two phenomena in one map (i.e. bivariate scales). Specifically, the extrinsic and intrinsic methods will be compared using two different types of tasks: The participants will be presented with maps that provide information on soil moisture and soil depth, and will be asked to identify the areas that meet the required conditions (e.g. area with the highest soil moisture and low soil depth). The research sample will consist of university students of humanities and social sciences, for it is our intention to focus on the people with no significant cartographic experience. In order to explore the collected eye-tracking data, an explorative analysis will be used. The main objective of the analysis will be to find out whether either of the bivariate scales requires more saccades to accomplish the task, requires more direct transitions between the legend and the map, and whether the different visualization types induce different cognitive processing methods. Our results will shed some light on the topic of computational (non)equivalence of the extrinsic and intrinsic visualization methods. The presented study will provide a basis for the upcoming cross-cultural research. The paper presents the suggested experimental design of the research and the means of analysis.