That's a filter, but I would say thats more of a cultural or mating response than an actual relationship. Looks are not the basis of a mental relationship, but a physical one maybe.
But is that not what is forced upon us over the years via media, relationships are built on looks and sex, rather than soul and intelligence. Too many of my friends relationships have broken down over the years as once the sex got "samey", they had nothing left as a common interest. I suppose though as they grow older they do eventually learn that whilst its great to have a really nice wrapper, its the sweet inside that you have to eat. Besides, looking is fine, touching isn't. Heck my parents (over 60 years old) comment on womens bodies togethor. If you werent looking at people you were attracted to how could we tell that you were still alive , besides you never will know when you are annoyed with your partner and need a mental bag (aka someone elses face/body) to get you going for the night. You may not look at the fireplace when stoking the fire, but you do have to look up occasionally to not bang your head on it!
It's not a foundation, it's an activity, and once they get bored of the activity they realize they have no foundation.
It may be an activity, but it is the foundations of emotional entanglement, though different sides of the relationship put different levels of value on it. At times its harder for men to make an emotional attachment from the act, though a lot of women see that the entry is creation of attachment. Most things do depend from which side of the fence you are looking from (blue or pink).
