The Neural Bases of Graphical Perception: A Novel Instance of Cultural Recycling?

Graphical representations of quantitative data abound in our culture, and yet the brain mechanisms of graphicacy, by which viewers quickly extract statistical information from a data graphic, are unknown. Here, using scatterplots as stimuli, we tested two hypotheses about the brain areas underlying graphicacy. First, at the perceptual level, we hypothesized that the visual processing of scatterplots and their main trend recycles cortical regions devoted to the perception of the principal axis of objects. Second, at a higher level, we speculated that the math-responsive network active during arithmetic and mathematical truth judgments should also be involved in graphical perception. Using fMRI, we indeed found that the judgment of the trend in a scatterplot recruits a right lateral occipital area involved in detecting the orientation of objects, as well as a right anterior intraparietal region also recruited during mathematical tasks. Both behavior and brain activity were driven by the t value that indexes the statistical correlation in the data, and right intraparietal activation covaried with participants' graphicacy level. On the basis of this first approach to the neural bases of graphical perception, we suggest that, like literacy and numeracy, graphicacy relies on the recycling of brain areas previously attuned to a similar problem, here the perception of object orientation.