Labeling graphs for improved reading speed

Three methods of labeling graphs were compared: (1) direct labeling of the functions; (2) a key inserted on the graph field below the functions; and (3) a key inserted below the figure in the position of the figure caption. In both a separate-groups comparison and a subsequent within subjects comparison, direct labeling reliably gave the quickest readings (p < 0.01) without loss of accuracy. Reading the labels directly on the functions appears to involve fewer steps and to depend less on short-term memory.