I think also the term "friend" is often misused.  True "soulmate" friends would likely bring delight while mere "acquaintance" friends would not.  I did not see the article clarify this aspect.

The full 23-page report is more than I have time for, but I downloaded it, and looked a some of it.  It seems fully consistent with known facts. The surprising result is the conclusion about intelligence, which is the thrust of Luke's bringing it here.

Recent theoretical developments suggest that general intelligence, far from being domain-general, may also have evolved as such a domain-specific evolved psychological mechanism. It may have evolved to allow individuals to solve a wide variety of nonrecurrent adaptive challenges that also directly or indirectly affected survival or reproduction. All such non-recurrent adaptive problems were evolutionarily novel. General intelligence may thus have evolved to solve evolutionarily novel problems, as a psychological adaptation for the domain of evolutionary novelty.

 

In other words, the key to survival is not learning per se, but figuring things out de novo.

"Our results also show important interaction between such evolutionary limitations and general intelligence and suggest that more intelligent individuals might suffer from affective consequences of evolutionary limitations on the brain to a significantly lesser degree than less intelligent individuals might." 

In other words, intelligent people are not ruled by their emotions.

"Despite using a large, nationally representative sample with over 15,000 participants, a limitation of the current studies is that the data are correlational. Although we have considered and potentially ruled out some alternative explanations, we cannot be sure of any causal relationships until experiments are conducted. Accordingly, future research should attempt to..."

 

They don't have all the answers, but the questions are interesting.

Myself, I prefer city life, although NYC - called "The City by those there - is more urbanism than I need. That is shown by the basic facts of the study that people are happier in the country than the suburbs, the suburbs more than small cities, small cities more than large cities. It is also interesting to ask more basic questions about "happiness."  Ayn Rand said that the frown is the touch of God on man's forehead. The study cites the fact that in China those in rural communities are much happier than those in cities, despite the overwhelming physical comforts that city people enjoy vis-a-vis their country cousins. 

Moreover, we see this same sort of dichotomy starkly in the Objectiv-ish and conservative blogosphere. Everyone wants to "go Galt" and run off to the country, to life in a small group of 100 people away from the cities.  They want to be happy.  I cannot say that they lack intelligence. These are engineers and physicists.  But, then, if you peel away the layers...  I don't have a lot of numbers for this, but I wonder about the extent to which even a Rand-fan engineer or physicist only learns which is presented - "evolutionarily recurrent problems" - as opposed to solving new problems.  I suggest that those who change careers would be closer to the evolutionarily novel experience, whereas those who work in the same field their whole lives are living in the "savannah mode."

Maybe it [a theorem given as an example by Marotta] is as arguable as evolutionary psychology, but that was not the purpose of that paper.

If the paper is reporting something as true, but the actual truth will rest on the accuracy of an assumption that isn't sustainable, who cares what the purpose of the paper is?

Nearly all of the social sciences have found themselves going off in wildly unsupportable directions because they keep building on invalid assumptions.  It isn't just that evolutionary psychology has problems as such, but that it too is built out of assumptions that shouldn't be blindly accepted.  The concept of "intelligence" is also generating bad research when it is used without a sound definition (which is most of the time).
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Put another way, in a county with low population density (41 persons/km2, one standard deviation below the mean), less intelligent individuals had higher mean life satisfaction than more intelligent individuals did. In contrast, in a county with high population density (937 persons/km2, one standard deviation above the mean), more intelligent individuals had higher mean life satisfaction than less intelligent individuals did.

I look at a statement like that and I'm just bewildered that more people don't see the problems in it.  What is "intelligence"?  How are they measuring it?  What is "life satisfaction"?  How are they measuring it?  This isn't real science.

Marotta, this isn't about my not liking the studies, and certainly not about not understanding the subject matter (please remember that we are in my area of formal expertise... I've actually had classes devoted to the measure of intelligence and classes devoted to the way psychological tests are created and administered.  What about you?)

Let me put if very simply.  I don't believe that they are measuring intelligence.  I don't believe they have defined "satisfaction with your life" in a sufficiently objective fashion - their likert scale doesn't get the job done.
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I also have problems with the various forms of self-reporting measurements.  If we want to say that there is a form of "satisfaction with your life as a whole" that is real, we should also recognize that self-reporting is subjective and there are some serious issues regarding the accuracy with which the objective element in question is measured by this subjective approach. 

It would be like someone defined "intelligence" as measurable by the number of hours one had in formal schooling, and then took a poll on how much people liked to party (say one a scale of 1 to 5?), and deduced from the resulting statistics that people who partied were more intelligent, or, perhaps, that partying led to higher intelligence.  At the end they could always say, "...we cannot rule out an opposite causal order to what we hypothesize..."

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Here is a real life example of an abuse of self-reporting as a measure.  There are a series of studies that were done where the researcher set out to determine if self-esteem had any relationship to success.  One study was conducted in prisons.  The prisoners were asked, I believe, 5 questions to self-report their beliefs about how confident they were, and how high their self-esteem was, and from that, using a likert scale, like this study did in their claim to have measured satisfaction, they decided that convicted inmates showed higher levels of self-esteem than average people who had never been convicted.  When you work with people it becomes important to find ways to weed out the subjective.

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I have been talking about the processes we see in much of the research coming out of the social sciences.  I don't have to read this paper to do that.  I have no interest in reading a paper that pays great attention to regression analysis of dependent variables but not to the definitions of the objects they claim the numbers represent.
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My question is this: Do you deny the truthfulness of the conclusions of the study?

Do I think they are engaged in a purposeful deceit?  No.  I see no evidence that they are lying.  But that doesn't mean that the study automatically represents an objective truth about reality.  You quoted this from the study: "...we cannot rule out an opposite causal order to what we hypothesize..."  So, they don't know if 'A' caused 'B' or if it was 'B' that caused 'A' and, by the way, they have no definitions of what 'A' or 'B' actually are.  The two elements you've written about are "satisfaction" and "intelligence" - does anyone think it would help to say what there actually are?  A study has to make sense, its key assumptions have to be sound, its key elements defined, otherwise it is hasn't a claim to "truthfulness."