Graphical Aids to the Estimation and Discrimination of Uncertain Numerical Data.This research investigates the performance of graphical dot arrays designed to make discrimination of relative numerosity as effortless as possible at the same time as making absolute (quantitative) numerosity estimation as effortful as possible. 
Graphical Aids
Similarly, human subjects report significantly lower levels of subjective confidence in judgments when using hybrid dot configurations as compared with regular configurations; and significantly higher levels of subjective confidence as compared with random configurations. 
hybrid dot configurations
However, discrimination of relative numerosity is significantly more accurate for hybrid dot arrays than for random dot arrays. 
random dot arrays