(Linda Davidson / The Washington Post)

How do you build an environmentalist — somebody who opposes the Keystone XL pipeline, tries to cut back on energy and water use, joins a green group or (maybe) drives a hybrid or electric car?

Recently, psychological and social science research has homed in on a number of factors that seem to predispose people to developing a “green” value system or world view. One is having an “open” personality — wanting to try new things and experiences.

Another is having high levels of compassion or empathy; attentiveness to the suffering of others seems to translate into attentiveness to the suffering of nature, too.

[The surprising psychology behind why some people become environmentalists]

But just because you’ve found a relationship between two traits that stands up statistically in a psychology study doesn’t mean you’ve explained the entirety of a phenomenon like environmentalism. Typically, these individual studies just give us little pieces of a broader story – think of them as providing one color in a landscape painting.

So what are some of the other colors? Recently published research in the journal Environment and Behavior has detected another factor involved in the shaping of an environmentalist, and this one is social rather than psychological (not that these two things can ever be fully disentangled). The factor? Spending more time with neighbors and friends, as opposed to spending it with your relatives. The former was associated with pro-environmental views and behaviors, and the latter, fascinatingly, with their opposite.

The study, by Thomas Macias and Kristin Williams of the University of Vermont in Burlington, turned to that vast repository of data on Americans, the General Social Survey. From the gigantic dataset, they pulled out several key variables — including not just how much people behave and think like environmentalists but also how much “social capital” they have. The latter is measured by variables such as the number of “social evenings with relatives,” “social evenings with neighbors” and ‘attendance of religious services.”

The basic idea of the analysis was simple, inspired by the famous “Bowling Alone” thesis of Harvard political scientist Robert Putnam. That thesis posited that people who have stronger social ties may care more about the environment, in part simply because, among other things, those social ties can be mind-broadening.

“Frequent interactions with neighbors, we hypothesize, may increase the opportunity to share locally relevant information and resources as well as help to lessen the distorting pull of media representation and social inequality on consumer expectations,” write Macias and Williams.

The data bore this idea out. Specifically, the researchers found that people who spent more “social evenings with neighbors” were more inclined to “use less water,” “buy chemical-free produce,” “use less household energy” and “drive less.” In contrast, people who spent more “social evenings with relatives” were less likely to cut back on driving and were also less willing to sacrifice for the environment by paying higher taxes or higher prices for various consumer objects.

So what explains this? For the positive effect of neighbors, the researchers postulate better informational exchange with people who are knowledgeable about what’s going on in a community — which increases the chance not only to learn new things but also to have one’s own views expanded. “Regular interactions with those nearby create opportunities to share resources and low-impact alternatives to the status quo,” they write.

That’s not surprising – and indeed, anti-environmentalist values have often been linked with support of the status quo (and vice versa).

The negative influence of relatives is more interesting. The researchers’ explanation for it is that that there may be more shared assumptions in tight-knit family circles than in broader, more diverse ones. And those shared assumptions may cut against environmental concern.”We hypothesize that people with a greater frequency of interactions among their bonding ties [those with whom we are closest emotionally] would tend to encounter fewer challenges to status quo perspectives and thus be reluctant to engage in conservation or other behaviors that might lower human impact on the environment,” write Macias and Williams.

Interestingly, one of the psychological factors cited above — openness to new experiences — probably works in concert with this newly identified social factor. Open people seek out new experiences, including new human interactions, and thus go beyond familiar circles more to hang out with relative strangers. So their social encounters probably interact with their inherent psychologies to predispose them to environmental views and concerns.

[Can your personality explain how you feel about the Keystone XL pipeline?]

The implications of the research, the authors conclude, is that we shouldn’t just be targeting people individually to get them to change their environmental or energy-related behaviors. Rather, we should be targeting their social interactions.

“Policies that foster social interactions at the community level through online forums, neighborhood organizations or local opportunities to volunteer may prove in the long run to be at least as important to addressing environmental crisis as social marketing aimed at promoting household efficiency improvements,” Macias and Williams conclude.