In reading Robert Sommer's article on Personal space many ideas about space were either re-confirmed or newly introduced to me. For my dining space two principles stand out as most important. First is the limit of comfortable conversation. Second is the idea of psychological intimacy in regards to seating patterns.
Comfortable conversation usually occurs within about 5 ft of any two individuals. If in conversation typically they prefer to sit across from one another. However, if given the option to sit next to someone to converse the distance should be less than a secondary location that is across from one another. Basically, given two seating options, one across from each other and the other next to each other, the will sit next to each other only if the distance is shorter than the distance across from each other. In designing a table for a dining space this would tell me that if a rectangular or oval table should not be any wider than 5 ft. This would allow individuals sitting at the ends, or head, of the table to engage in conversation to those directly adjacent.
The idea of psychological intimacy relates more to how people sit next to other individuals when given a choice. His article speaks a lot about studies where individuals are told they are in competition, working with, or becoming friendly with another individual. For me this information suggests that a round table is the most appropriate choice for all individuals. Oval would be a good shape as well, especially if seating more than about 5 or 6 people. This encourages conversation from everyone and leaves no one in a conversationally dead spot.
In my experience a round table that seats more than 6 starts to become to large for comfortable conversation. The dining space that I am designing is for at least ten sot his would rule out a round table. Oval seems a more pleasing shape and slightly less formal than a rectangular table. This reduced intimacy would create a more relaxed dining environment and encourage a more friendly form of conversation.