Obviously someone not getting enough calories to live would lose weight as they starve; the question is whether they could lose weight without being continually sick, weak, and half-insane with food cravings. Maybe a drill sargent with a cattle prod could force them to exercise; or maybe they would turn out to have undiagnosed cases of chronic fatigue syndrome. And surprisingly enough, hunter-gatherers who are otherwise fit seem to very commonly be paunchy; not a six-pack in sight.
Two punches, or two gorillas?
After they’re dead, they’re probably equally happy. 
See also here and here.
But more seriously, a gene implicated in aggression controls levels of MAO-A
A human project would take much longer than the foxes because we breed faster. The foxes were/would be well stabilized by generation 100.
I am not up on the literature, but I know that data exists for that question, and depends on the trait. Obviously it is correlational, but I’ll guess that genes have a stronger influence than most people assume. What you might find is that e.g. a gene for thrill-seeking would cause Mr. Crappy Childhood to become an armed robber and Mr. Nice Parents to be into extreme sports, but the gene is putting them both in dangerous, antiadaptive situations.
Also, these critters.
As several dopers have noted a lot of these isolation experiments have already kinda-sorta been done on humans (without controls) and monkeys (with controls). It usually leaves the child permanently crippled cognitively and emotionally.
Per Shagnasty I’m not clear that anyone is claiming some obese people can’t lose weight period through dietary restriction and exercise, only that some obese people claim it is very difficult to do this re getting calories low enough to show significant weight loss without suffering other negative health effects.
I’m at the low end of the human metabolism speed range and (based on years of calorie counting) it takes about 9 - 10 calories per lb of body weight per day to support my weight even though I exercise intensively 3 times a week for one hour at a time and walk several miles at a time 2-3 times a week. This means I could support a weight of 225-230 lbs on 2000 -2200 calories a day even though I am pretty active. That is not a lot of food for 6’3", man but that’s my world.
Assuming, based on random genetics, there is some obese individual as a statistical outlier that only needs 7-8 calories per lb of body weight per day. That person would weigh 300 lbs eating only 2100 -2200 calories per day. Assuming their target weight is 180 lbs they can only eat 1,260 calories per day to maintain that. That’s a big lunch.
Do people like this exist? I’m sure they are rare, but I don’t think I’d bet that they don’t. I’ve lost weight when I was younger doing stupid starvation diets of 1200 calories per day. I can’t conceive trying to exist like that long term. If someone has super slow metabolism clock and high-normal appetite I can see them feeling that weight loss dieting is a horrific gauntlet vs just a PITA.
Find a member of any royal family having blue blood.
Ha, I entered this thread to say “Humanzee.” Beat me by a long shot!
I confidently predict that neither will be in the least happy or successful after they are dead.
The trick is getting close enough without her tearing your face off
I’d splicing all kinds of human/wild animal hybrids.
I’d also like to find out if you took a baby and raised him in total isolation for 18 years and then stuck a naked lady in front of him, would he get aroused? Or in other words, how has his libido developed?
Think big !
Stop all greenhouse gas emissions for 20 years. See if the climate recovers.
Build a high fence around a theoretically self-sufficient country and turn off their government. After 10 years, see if the survivors are better off economically, and if they have naturally formed a new government.
I’ve worked with the kids/people who grew up in the Romanian orphanages we heard about in the '90s. That’s something of an indication of what happens when children are raised without nurturing and suffering sensory deprivation: they become severely developmentally disabled. They rock and hit themselves to self-stimulate, they don’t develop language, they don’t develop normal movement. They probably have something resembling a libido, but I doubt it could even meaningfully be assessed.
IME all the “raising children with nothing/on an island/no language/no nurturing/etc” is less interesting than you’d think. It’s mostly just very sad.
I saw a picture of one of the (ahem) “orphanages” where some of the people I worked with came from, and they had rows of cots and people bottle feeding two at a time, standing between the rows. 
Isn’t “Life as we know it” one big experiment without ethical concerns?
I would like to try to settle once and for all whether a severed human head can retain any level of consciousness.
Put somebody in a contraption that’s basically a guillotine turned sideways, with the head held firmly in place. Have tubes and a blood supply ready. The instant that the head is severed, place the tubes into the blood vessels, and start up the blood supply. If all this is done very quickly, I think it would settle the question.
Far be it from me to lower to tone from severed heads and humanzees, but I think it would be interesting to run some experiments in the social sciences to try and validate theories of economics or psychology. Part of the problem with these theories is that you don’t have a control that you can use as a measurement baseline, and all discussions around what to do devolve into a shouting match with no real proof to support either approach. Let’s have some rigour in these experiments, people.
So, for example, take two identical countries and subject them to very different economic regimes - say complete free-market economics vs highly regulated banking, and see which one has more desirable outcomes. Perhaps this would been to be run several times over to get some sort of statistical result. Run a similar experiment for universal government provided health care vs private health care, and document all the results. That sort of stuff.
Of course, you’d have to be some ultra-long-lived alien race to be able to start the experiment and see the result in a single lifetime, but what sort of reason is that not to pursue the idea?
The stuff that comes to mind is more…focused/concentrated versions of experiments that play out in our world.
Eugenics/Euthanasia/Spartans vs Save All/Athens (?) - my attempt at naming may be completely off; sorry: a multi-century/generational study where one population has no/VERY limited access to genetic cures - i.e., let all “the weak” die and the strong breed - vs doing everything to save everyone.
Fully legal drugs of all kinds - for sports and recreation - vs drugs only for medicine. Which population does better - along what measures? Over time?
(Sorry I realise my earlier post may seem a little threadshitty because we’re leaving out ethics, it wasn’t my intention! What I wanted to say was just that raising children the “island” way IME does not give spectacle and fireworks, but mostly just a whole lot of nothing. But in ethics-free world, please carry on isolating 'em for science :D)
Find out whether you die if you burp, fart and sneeze at the same time.