I don't agree. Obviously this is all conjectural because we don't have any real world point of comparison, but in my opinion a different species, with a different biology, could have a very different outlook and attitude from ordinary humans. If I could expect to live for hundreds of years, if I was smaller than most other sentient beings, if my body was especially well-suited to live underground, I think it would definitely have a strong influence on my personality.
Really? I find that extremely surprising. The fact that humans live to be 80+ rather than 40ish has not had "strong influence" on
personality, people in general still have the same general behavioral patterns they had before. Growth and development on a very long scale is somewhat different, e.g. Erikson's "stages of psychosocial development" may possibly admit the addition of a new stage between adolescence and adulthood covering the modern "college student lingering at/near home," but by and large people have been people regardless, and core personality attributes don't appear to be that much different now than they were in the past.
I also think you're vastly playing up the amount of biological difference. Elves are humans that live a really long time--that's it. Dwarves are (slightly) short humans that live longer than we normally expect (I say 'slightly' because some games classify them as "small" like halfings, while others classify them as "medium" like humans). Aesthetically, dwarves may prefer different design because they're shorter, but "averages ~1.5 feet shorter than humans" is going to have about as much effect on culture as "tends to be left-handed." Halflings are more or less equivalent to the pygmy peoples, who are just as much another kind of human, and to the best of my knowledge do not have cultures so alien that you could (to greater degree than chance) distinguish a pygmy from a non-pygmy in a Turing-like test. Again, as I've said several times: basal/physiological needs are the same for essentially all races ("nutrition" though not necessarily "food," air, shelter, regular rest, etc.), logic works the same way for all of them, and (excluding rare quadrupeds like centaurs or sentient bears etc.) they all have identical body plan and near-identical appendages. That constrains the range of physiological changes substantially!
I was already told that simple physiology differences (e.g. tails, presumably stuff like being cold-blooded) aren't what was being discussed. So the only differences I can think of that really deeply matter are:
- Laying eggs, physically constructing/cloning offspring, etc.
- Altered sensory apparatus (lacking eyes, seeing infrared or "magic," internal chronometry, telepathy, etc.)
- Being a non-animal (sentient mineral, construct, plant, etc.)
- Dramatic physical abilities (invisibility, flight, etc.)
Of these, the majority don't apply to most races...so I'll grant you that they
should influence behavior, but only for races that would make sense. Wilden and Warforged, for example, are pretty distinctly divergent from the human norm, so I wouldn't be surprised by divergent behavior. But Elves and Dwarves are so close to the human norm that we can approximate them with human beings who adopt particular mannerisms, and mannerisms are
exactly the kind of cultural thing I've been talking about all along.
Think about elves for a second. Baron McEvilton is oppressing his peasants so the human PC decides to go all Robin Hood and save the peasants. The elf looks at this and thinks, "Well, the Baron is 40 years old now. He's going to likely die in the next twenty years. This problem is self correcting"
Why would an elf care? Bad leaders come and go in the blink of on eye to an elf. Any problem that isn't going to last more than a century isn't really a problem is it?
And how often does this kind of behavior come from
players? Elf Buddy is an NPC--or behaving like one. He has the leeway to decide, "Eh, screw it, I can wait it out." PC adventurers are not nearly so sessile--it is
boring to defeat your enemies by outliving them. So this seemingly "super-important" element (lifespan differences) evaporates when inserted into the "we're playing a game" context. Especially if the party isn't all long-lived aloof jerks--and the amount of aloofness and jerkness will, again, be much more dependent on culture than race in particular.
There's also the simple fact that Baron McEvilton can establish a lineage, whether biologically or grooming a successor--or simply being replaced by someone nearly equivalent. So even the long-lived, aloof, uncaring Elf Buddy may have a reason to do something. "You are like blackberries. The individuals may die, but the roots linger and multiply!"
Or, to riff on the words of M. Bison: "For you, the day Elves graced your village was the greatest day of your life. For us, it was pest control."
Culture obviously plays a part too and should not be ignored but species is just as important.
Yeah, I really truly see culture as being substantially more important. Sometimes, that culture will be in part influenced by biology, but the culture itself is where the effect lies. If dragonborn laid eggs, for example, then their attitudes toward child-rearing would probably be different from those of a race that has live birth, and different again from those that don't give birth at all, but (essentially) all playable races will have attitudes about the coming-into-existence and propagation-of-the-species things, and those attitudes will be at least analogous to (albeit not the same as) real Earth cultures. For instance, long-lived, space-conserving races will probably end up displaying long-run behavior like that found in modernized nations e.g. Japan/Europe/USA, where birth rates are low but survival rates are very high.
And whether any given race, long-lived or not, engages in active interference is going to depend far more on their cultural values. Roddenberry's Federation and Banks' Culture are (very roughly) analogous entities, but the former has an EXTREMELY strict non-intervention policy (despite the violations shown on TV) and the latter sees it as their
moral duty to make other cultures become more like theirs. Then you have things like the Draenei in WoW: they definitely have a distinct culture, and a light dusting of the "smug superiority" thing that Elves often get...but their superiority usually takes the form of wanting to help "lesser" races improve, though not to the deep-interventionist level of The Culture.
Imagine if Spock, or Worf or Thorin were human. Would they be the same characters?
Sure they would. Amanda Grayson is the equivalent of a woman of one culture marrying into a very different one, and Spock is a man with a dual cultural heritage struggling to reconcile them. A friend of mine, for example, is German-Irish-Hispanic, descended from both conquerors and natives on her mother's side; reconciling her cultural heritages is something she's thought a lot about.
Worf is equivalent to the "dwarf raised by elves" example, which is (essentially) equivalent to cross-cultural adoption. So that's even worse of an example, since you (as I understood it?) conceded the "dwarf raised by elves" thing earlier.
Thorin is already essentially a short human who comes from a culture that espouses a particular set of virtues (being a warrior; industry; hoarded wealth). Can you explain further why you chose him in particular? Because as far as I remember (from the books--I didn't watch beyond the first Hobbit movie), Thorin doesn't have any motives or values that couldn't be found in a (theoretical) Earth culture. Plus, the dwarven lifespan really
isn't different from the lifespans humans can (theoretically) enjoy in Middle-Earth anyway. Both are mortal, but at least the Numenoreans and (some of) their descendants could live for centuries and
decided when they wanted to die. Aragorn/King Elessar did precisely that, living to be over 200 years old and ruling for 120 of it. (Remember: when he joins the Fellowship, he's
87 years old. Pretty spry if you ask me!

)
Edit: I'd also say Gandalf rather neatly pokes a hole in this question. He's not at all human, he should be even more removed from human concerns than an Elf would be since he's a
lesser angel in human guise. Yet he loves pipeweed and a good beer, makes fireworks for fun, and for all his vast knowledge he can still be tripped up by simple wordplay. And even for people who know his name, all it takes is slightly playing up his appearance ("You would not part an old man from his walking stick...") to get them to forget that he is a powerful wizard.