Aligning Data Visualization with Human Cognition: A Novel Approach to Large Numbers.

​presentation by Katerina Batziakoudi, PhD in Data Visualization with the AVIZ team at Inria

​Dr Batziakoudi's research is about helping people make sense of very large numbers—like the thousands, millions, and billions found in public budgets— because common linear and logarithmic charts make these values hard to compare and understand.

​Instead of treating this only as a visualization problem, she studies it as a human understanding problem: how people naturally think about large numbers, and how charts can better match that way of thinking.

​In particular, this work builds on psychological findings that people do not perceive large values as purely linear or logarithmic; rather, we tend to mentally chunk them into groups such as thousands, millions, and billions, and reason linearly within each group, much as numbers are expressed in language. Based on this, she designed and tested novel visual representations that align with this piecewise linear way of thinking. Across a series of experiments and real-world evaluations, including work with journalists exploring national budget data, she shows that these designs can make comparisons easier, reduce mental effort, and improve confidence in interpretation.

​More broadly, this presentation proposes a design approach for visualizing extreme numerical ranges that is grounded in how people actually reason about numbers.