Do network diagrams that are entirely irrelevant to a task, drive local and global processing? Two types of diagrams, （1） Convergent diagrams having a core in the center with elements converging at the core, and （2） Divergent diagrams having no core with multiple elements diverging at random were investigated to test the following hypotheses： Task-irrelevant convergent diagram would facilitate local processing, whereas task-irrelevant divergent diagram would facilitate global processing. In Experiment 1, positive and negative face judgment tasks and in Experiment 2, local and global letter judgment tasks, in which diagram stimuli were presented as primes were conducted. The results indicated that task-irrelevant convergent diagram significantly facilitated local processing, whereas task-irrelevant divergent diagram did not facilitate global processing. Based on these findings, efficient use of diagrams in information design is discussed.

A police car has a distinguishable outward appearance. Due to its atypical usage in police activities, police car visibility is important to prevent collisions with other traffic parties. In the current study, a fundamental investigation of computer-based experiments was conducted to clarify the inuence of vehicle rear end designs on the estimation of headway distance. Results revealed that estimated headway distance deteriorated when “POLICE” signage was supplemented. Furthermore, it was also revealed that an alteration, through the addition of an underline to the “POLICE” signage, would likely improve the estimation of the distance within this experimental environment.