“This is a film about why you should join a club,” says director Pete Davis in the documentary “Join or Die,” which he made with his sister, the filmmaker Rebecca Davis.

It recently became available on Netflix and feels suited to the moment.

If you’ve been feeling depleted and disconnected from a world of diminished meaningful in-person interactions, “Join or Die” explores one reason why, as laid out by social scientist Robert Putnam. Collectively, we’re less involved in organized gatherings. There are all kinds of reasons for that, but it’s a fundamental shift that’s affected our quality of life, because the social bonds that result when you join a club or organization are not just a matter of “warm, cuddly feelings,” Putnam says in the film. “In area after area of our community life, our communities don’t work as well when we’re not connected.” And that, he says, has far-reaching effects not only on us as individuals, but on democracy itself.

Putnam started formulating his ideas while working as a researcher in Italy early in his career.

In regions he describes as “uncivic,” he found that people view public affairs as “the business of somebody else — the bosses, the politicians — but not me. Engagement in social and cultural associations is meager. Corruption is widely regarded as the norm, even by the politicians themselves, and they are cynical about democratic principles. Trapped in these interlocking vicious circles, nearly everyone feels powerless, exploited and unhappy.” And that trickles out to the systems meant to serve a population: “All things considered, it is hardly surprising that representative government here is less effective than in more civic communities.”

Best known for his book “Bowling Alone: The Collapse and Revival of American Community,” published nearly 25 years ago, Putnam comes across as a perpetual optimist and that quality buoys much of the film.

“America doesn’t have to be the kind of America you’ve lived in your whole life,” he says. “I want America to change. I want America to get better.”

Even when he’s comparing trends from the 20th century to today, he’s not saying the old days were better, just that participation in clubs used to be more prevalent. “The thing that has actually most concerned me about the debate about ‘Bowling Alone’ is that some people thought I was saying life was much nicer back in the ‘50s — ‘Would all women please report to the kitchen’ — and that’s not what I’m saying.”

Pete Davis took one of Putnam’s classes in college in 2010, which is how they met: “Back then,” Pete says, “most of us were feeling pretty good about where America was heading.”

That’s not how I remember it. Two years out from a major recession? The year the Supreme Court handed down its pivotal Citizens United ruling? The year of the Deepwater Horizon oil spill? I don’t know that “most of us were feeling pretty good about where America was heading,” but more importantly, it’s not relevant to the film’s larger points. The documentary improves significantly when Peter takes the focus off himself and talks, simply and plainly, with Putman and others about why any of this matters.

Putnam’s thesis is that communal activities build social ties, which have value beyond the immediate satisfaction of just doing things together. It creates a sense of mutual obligation.

Putnam puts it this way: “The reason social networks are important is that they mean that if you cheat somebody, other people will hear about it. The more I lose by cheating, the more likely I am to be honest. That leads to the core idea of reciprocity: I won’t cheat you if you don’t cheat me.”

And that, he says, fosters a sense of generalized reciprocity: “I’m going to be nice to you just because you’re in this community and you’re likely to be nice to me. That’s a huge deal. If you can have generalized reciprocity in a community, that community can be enormously more productive because they don’t have to be constantly checking up on one another — I’ll do something for you without expecting something right back because down the road, somebody will do something for me. And anyhow, we’ll always see each other at choral practice. Social capital produces trust and that trust produces lots of good things.”

Political scientist Hahrie Han says those effects extend out: “Most political scientists think of politics as being a function of the effectiveness of our political institutions — Congress, Supreme Court, presidency — and Putnam said it’s also about the way people are connected to each other.”