A recent study from the "Sage Journal" notes that participants of counseling sessions were more open and interactive when surrounded by dim lighting. The softer lighting also improved their opinion of the counselor and contributed to a more-relaxed state of the participants. Select lighting fixtures with dark lampshades or overhead lighting with translucent glass covers or replace your light bulbs with lower wattage bulbs.
The "Sage Journal" also reveals that the differing decor of the counseling rooms did not have any significant impact on the participants, indicating that decor does not specifically impact communication. However, choosing interesting art and artifacts to place judiciously in your home will encourage communication with new guests who are in your home for the first time and leaves a memorable impression.
Consider the placement of doors and walls when remodeling. Opening up all, or part of, a wall between a kitchen and great room or kitchen and dining room facilitates increased communication during meal times and when entertaining. However, closing a few doors allows family members to feel enclosed and calm, and encourages increased intimacy when talking.