Minimalism and the Syntax of Graphs

Abstract

Four experiments examined Tufte's syntactic rule that graphs should have maximal data-ink ratios produced by erasing non-data-ink and redundant data-ink. In Experiment 1, the data-ink ratios of bar and line graphs affected the accuracy and response times for comparison, difference, and mean questions: the higher the data-ink ratio, the faster the response time and the greater the accuracy. Experiments 2 and 3 showed that the effects of ink in the syntactic elements of a graph depend on the location and function of the element: redundant ink in the indicators had limited effects on performance, pictorial backgrounds generally increased response time and decreased accuracy, y axis tick marks generally increased response time, and the y axis line and the x axis generally decreased response time. The effect of each graphical element was conditional on the type of graph and task and the presence of other graphical elements. The discussion focuses on psychological principles that may underlie the effects of each syntactic element.