The combination could also be seen in my children as they became softer, more feminine and tidier. Just recently my cousin also arrivedfrom Australia. The tidiness level dropped but the house seemed fully and richer, less stagnant. I worked faster. Another character had arrived on the scene and the movie set of the mind changed.
Human behavior is exactly the same.
Imagine the mind like a house. It has many rooms and characters. If the characters are asleep, the house is quiet. If one character is too loud, it will drown out the other characters and the house will not function properly. If the characters in the house decide to pool their resources, the house will expand and grow, affecting all those around.