Eric Berne argued - and studies seem to show - that people need to get and give strokes. Call that 'physical need' if you want, but I call that 'emotional need'.
No doubt in my mind, studies have shown that physical contact, ranging from a hug to an orgasm, do release neuro-chemicals that alter moods, generally in positive ways, though if one finds the contact repellant due to the nature of either the type of or person performing the contact, the effect will not be positive.
I get very positive responses from doing dishes or laundry or bringing home a gift - but I do those things to express love, not to get the responses, however much I enjoy them.
I do dishes or laundry because I need clean clothes and dishes. Something about living too close to nature and all it's filth bothers me.
Kinda goes along with this, from the Big Bang Theory.
Sheldon Cooper: If outside is so good, why has mankind spent thousands of years trying to perfect inside?
I use the love language stuff because I expect my W is more likely to notice an act of service as an expression of love than, say a physical stroke.
My W expresses love by putting a lot of effort into acts of service, but they never meant much to me until I learned that's her primary LL. Now I experience an AoS as love - but she does more physical stroking than before, and that's my primary LL.
Excellent example to illustrate. I noticed long ago that I was far more likely to give my STBX a backrub if I was feeling sore myself. Perhaps knowing the primary love languages is really about recognizing the internal emotional weaknesses in oneself and ones partner. Maybe love does require compatible weaknesses? Ideally, if you respect your partner, their abilities, and their limitations, you can recognize the love that exists in whatever form it manifests, and not insist that there is a problem because it is not (as in the oranges example previously) in the preferred form. Sometimes love even consists of refraining from some of these. Refraining from acts of service one would really like to perform are a sign of love when it is something that a person needs to do for themselves, any parent who has watched a child struggle with something (like long division, if they still do that in school) where we could easily do it for them in seconds would understand this. The alleged value of any of these actions or things is also very situational. After a hard day when all the muscles are sore, a spontaneous backrub means the world, but after a long and tedious day it can be quite annoying as it prevents one from sleeping. The greatest gift I ever gave, one I shall likely never have the opportunity to duplicate (unless I am a genetic match for someone and they need an organ) was so highly situational, and would be completely worthless at any other time. It was early in our relationship, and I was a student, but one who knew where I wanted things to go. We just finished checking out at the grocery store, and walked past the gumball machines. One was filled with the cheap plastic toys, and I noticed a ring was inside. Thinking that I was broke, but she deserved a ring, I reached into my pockets and pulled out my very last dollar, called her over to the machine, and said something about deserving a ring and seeing what fate thought, I turned the handle, and out dropped a red plastic ring, with a clear bubble about an inch and a half across containing one of those shake the steel balls into the holes games. How does one beat that? And yet, if I were to ever do that again, the circumstances would make it meaningless. If I were to give one of those now and say I thought you deserved a ring, I would expect to get slapped.
At least in some ways, I love my W 1) because I like being with her, even if all we're doing is breathing together, 2) because she accepts and likes what I offer, and 3) I accept and like what she offers. I suspect that the 2nd is more important than the 3rd, and that the 1st is most important of all.
I think all of these are summed up by enjoying each others company, and thinking of and treating each other with respect. Might even go so far as to say that in such a nasty world, if you find a respectable person that thinks of and treats you with respect, you will enjoy their company.
All this talk of love languages is inevitably tied into the theory of the love bank. Another one that I find problematic. It's a nice neat simplistic way of describing a concept, but it has some really big holes in it. I would compare my thoughts on it to Heinlein's quote about the labor theory of value: "All the work one cares to add will not turn a mud pie into an apple tart..." The first questioning of the love bank theory I heard was from an accountant, which really got me thinking about it. Bank accounts are easy to track, you make deposits, withdrawals, pay bills, and can check the balance online, or get a regular statement, and if you have good credit history might even be allowed an overdraft. Banks will never refuse deposits, and the effects of making identical deposits are cumulative. Love doesn't work that way. If I bring home a chocolate bar as a gift, it may get me an appreciative kiss, but bringing home a whole halloween bag of the same chocolate bar, or even a pallet, does not automatically translate into blow jobs.
Not that there is an inherent problem with trying to adapt economic theory (which I consider to be more mass psychology than anything else) to love, but economic theory is far more complex than the zero sum game described in the love bank. It is more like a love investment portfolio, and you transfer in anything you can that you think has value, without knowing the current market rates, transfer out what you need under the same conditions, the statements are sent out quarterly to the wrong address, the market swings wildly, if at any time you cross a negative threshold you are barred from the market, and sometimes a third party will steal your investments via identity theft, or manipulate the market to your detriment with insider trading or short sales.