Abstract
This paper summarizes the results of a case study on how mobile phones are used among high school students in Japan and what impact this usage has on relations with friends.
It is said that the use of the cellular phone has had the effect of expanding interpersonal relationships. And, in quantitative terms, high school students do indeed have many more friendship relations now that the cell phone is nearly ubiquitous than they did when cell phone usage was just starting to expand. However, when paying attention to the qualitative aspects of interpersonal relationships, it was found that high school students and their relationships when cell phones have become essentially ubiquitous are like those of middleschool students. This suggests that the use of cell phones influences mental development during adolescence.
