We tend to talk to people we can make eye contact with—and people raised in the West are generally very, very positive about eye contact. Arranging seats in a sitting room so that all can see into each other’s eyes will mean that most stay involved in a conversation.
Nodes of chairs around the room can create conversation zones, which can work out best in a large space.
Everyone can get overloaded on eye contact, and this point is likely to come earlier for people raised in the East. Also, we want to break eye contact when we have something “difficult” to discuss. That’s when conveniently located focal points earn their keep. Having a piece of art or an outdoor view or a fireplace or something else interesting that people can gracefully divert their gaze to when seated makes needed “eye contact breaks” acceptable and not rude or evasive.
Generally, it works out best if everyone participating in a conversation is sitting in a seat that’s about the same height above the floor as everyone else. If we’re looking up at someone, we treat them as more adult and powerful/experienced and when we’re gazing down we categorize whomever we’re looking at as more childlike and less skilled. These distortions can make it difficult to have the sort of conversation we’ve generally planned. Also, when we’re looking up, say at a stage, we tend to think more abstractly, but when we’re looking down, as from a balcony, we think more concretely.
Having everyone in a discussion reclined can reap all sorts of benefits. For example, not only are we apt to think more creatively when we’re stretched out, we also are less likely to be angered by situations that would upset us in other postures. Maybe every home with teenagers should move out their conventional chairs and move in reclining chairs for the duration!
Leaders do tend to sit in certain positions, for example, in chairs with a view of the door or at a shorter end of a rectangular table. To keep conversations more “egalitarian” (if desired!) square or round dining, etc., tables are best. When square or round and room shape just don’t align, moving the chairs from the shorter end of a rectangular table to one of the longer edges is a reasonable fix/equalizer.
The best arrangement of seats, to build bonds between people talking, for example, are those where the front edges of those seats are at right angle to each other, as if people were talking across the corner of a table—so this should always be the default arrangement for any two chairs. We also prefer this “cross corner” configuration. Otherwise, men generally are most comfortable speaking with someone seated by their side and women to talk to people across from them.
Also, build some “extra” chairs into a space—we prefer environments where only about 70% of seats are in use.
Seating options that allow people to choose the right configuration for them at any particular moment are best!