These three together tell us what attributes of eye contact we need to support for small groups. We need use of eye contact to be:

- unconscious or involuntary (but deliberate if you want)

- visible to other people in the group

Out of that, as we can see with SMS and mobiles, you can grow the tentative requests for encounters and social grooming.

Two other aspects. You need to feel the presence of people around so you can decide to make eye contact.

And I'd prefer it to be polite.