Could the basis of love be the expectation of a future benefit? Say you meet an attractive person of the opposite gender (or of the same gender, as the case may be). You are attracted to this person because of one or more salient qualities, intelligence, personality, or good looks. You revel in this discovery and look forward to being able to enjoy this person's desirable qualities. More to the point, you expect that your appreciation of someone will help generate an appreciation of you by that person, with your other qualities doing the rest. Even if this person doesn't fully reciprocate, if s/he agrees to spend time with, and perhaps "date" you, this might be the beginning of love.

But suppose the object of your affection studiously ignores you, or worse, seems to date everyone except you, not noticing, or downplaying your attention and your good qualities. You no longer have any reasonable expectation of benefiting from whatever desirable qualities this person may have. Does your potential love now turn into hate, or at least jealousy?

Some people will poinr to the love of parents and children, and the fact that a parent may seem to blindly love a worthless child (or in a few cases, the opposite). But the fact is that the parent-child relationship is bound by real ties; each person possesses roughly half of the other's genes. That would probably create a strong expectation that whatever benefits the other person produces in life will accrue to you at some point.

Can love exist in a seeming vacuum, that is with the realization that the beloved does not have the power to benefit you in any way, or worse, has no intention of ever benefiting you in any way?
Can love ever be without expectation of benefit? It would seem that the actual experience of love, itself has a reward.


  According to licensed psychologist Dr. Rachel Needle, specific chemical substances such as oxytocin, phenethylamine, and dopamine, have been found to play a role in human experiences and behaviors that are associated with love. They function similar to amphetamine, making us alert, excited, and wanting to bond.


This is less of an answer, and more an expansion on the notion of altruism and human motivation. This question deals with the concept of morality, and embraces many concepts, including the Darwinian notion of survival of the fittest. (ie finding a suitable mate)

A superficial glance at this would suggest that any human interaction is based on fulfilling our needs, as a species.

I don't believe there is a definitive answer to this question. This question, crosses into philosophical realms, in defining love and the true nature of mankind, as a creature. The concept that  the individual seeks to benefit from a "relationship" when they love another person, also addresses the entire notion, of whether, as a species, we are motivated by any other than self interest.


  Can love exist in a seeming vacuum, ...



Nothing in the realm of humanity truly occurs within a vacuum. People's feelings, translate into actions, which cause ripples. (See ripple effect, butterfly effect, causality; as an indicator of my reasons for making this statement. It is more of a sociological discussion and so I won't go into it further).



  ... with the realization that the beloved does not have the power to benefit you in any way, or worse, has no intention of ever benefiting you in any way?



I do believe that many would say this is the definition of unconditional love. Which is where this becomes a philosophical debate over the concept of altruism.



  More to the point, you expect that your appreciation of someone will help generate an appreciation of you by that person, with your other qualities doing the rest. ...//... this might be the beginning of love.



The motivations behind attraction are complex. Yes, there is the instinct to find a partner and within this, there would be an expectation of benefit.



  You no longer have any reasonable expectation of benefiting from whatever desirable qualities this person may have. Does your potential love now turn into hate, or at least jealousy?



How people manage perceived rejection is a question on it's own. For some people, yes, unrequited love can turn into a poison, many move on and become indifferent.  This reaction, may have less to do with the concept of the loss of potential benefits from this person, than the complex nature of human relationships and the effects of rejection.



  But the fact is that the parent-child relationship is bound by real ties; each person possesses roughly half of the other's genes. That would probably create a strong expectation that whatever benefits the other person produces in life will accrue to you.



This again brings us back to the notion of our behaviour as a species. To a degree it is self interested to protect one's gene pool.


As to the attraction style of individuals, and whether they form patterns of seeking unavailable or unobtainable prospective partners, is another discussion in itself.