In the United States, friends often share intimate details of their lives and problems. However, such self-disclosure（揭露，揭发） is much less common in Japan. A new study by an American researcher living in Japan finds that this may be because of the different social systems in the two countries, and in particular the extent to which there are opportunities to make new friends. "At first, it seemed strange that in Japan, people didn't open up and share a lot about themselves with each other," says Joanna Schug of Hokkaido University. "But Japanese often look at Americans and think, 'Why are they telling me so much about themselves?'" Schug thought the difference might have to do with the way relationships work in the two countries, in particular the utility of investing in relationships by sharing personal details. In a society like Japan, where relationships are entrenched¹（根深蒂固的，确立的） within rigid² social networks (what the researchers call societies low in "relational mobility³"), relationship-maintenance strategies like self-disclosure are not as useful as they are in societies high in relational mobility (like the United States) where relationships are more easily formed and lost. It is in the latter cultures that people need to invest more effort into strengthening relationships that may be more fragile.

To test this idea, Schug recruited university students in both Japan and the United States to answer questions about their relationships. They indicated how likely they would be to tell either their closest friend or a family member about their biggest secret, their most embarrassing experience, and so on. They also described how the relationships around them work—for example, how much they think that people in their neighborhood, workplace, or other environment can voluntarily choose who they interact with. In another experiment, volunteers also shared the number of new friends and acquaintances（熟人，相识） they had formed in the previous three months.

Schug wrote the study with Masaki Yuki of Hokkaido University and William Maddux of INSEAD. The work is published in Psychological Science, a journal of the Association for Psychological Science.

Schug and her colleagues found that Japanese people were indeed more likely to feel that relationships were stable and because of this, were less likely to share so much information with their closest friend. However, Americans shared more information with friends than the Japanese because they saw their relationships as more fragile and shifting more often, thus requiring more maintenance（维护，保持） via self-disclosure. Schug says the study presents an interesting paradox⁴（悖论，反论） : Although the United States is a more individualistic country than collectivist Japan, investing in relationships may actually pay higher dividends⁵ in cultures that place an emphasis on the individual.