I imagine you have a textbook with the "official" answer to this question. I will try to answer based on my interactions with my Japanese friends living in the US.
From what I have seen, Japanese adults are much less likely to touch one another than Americans are. For example, my kids and I sometimes go play in the park with a group of Japanese women and their kids. When we go play with Americans, they tend to hug when they meet (especially if they haven't seen each other in a week or so) and they tend to touch while talking. The Japanese, by contrast, do not. In fact, one Japanese family went back to Japan and no one hugged anyone when we all saw them off as a group.
So I would say that Japanese do not use touching nearly as much as Americans do.