The technique known as perceptual mapping is often used to understand consumers' mental representations of brands within a given category. Traditionally two variables (often, but not necessarily, price and quality) are used to construct the map. A sample of people in the target market are asked to explain where they would place various brands in terms of the selected variables. Results are averaged across all respondents, and results are plotted on a graph, as illustrated in the figure. The final map indicates how the "average" member of the population views the brand that makes up a category and how each of the brands relates to other brands within the same category. While perceptual maps with two dimensions are common, multi-dimensional maps are also used.