Every Sunday this summer, we'll be taking an historical tour of the Hollywood blockbuster by examining an older film that is in some way a spiritual precursor to one of the weekend's wide releases. This week: pretty much everybody can tell you how Friends with Benefits fits into the strange trend of 2011 fuckbuddy movies, but the idea of a mainstream romantic comedy that takes a look at less conventional relationship than "boy meets, loses, gets girl" is much older than even No Strings Attached. In fact, once upon a time, such films could double as cultural flashpoints, and not just disposable entertainment.

You know what they don't make any more? Zeitgeist movies. Movies about normal, contemporary people that make a big splash and are talked about all over, and if you expect anybody to take you seriously, you really had better form an opinion on the thing one way or the other. And I don't mean Event Pictures, like your Avatar or your Lord of the Rings or that sort of thing. You're expected to have seen those, of course, and to talk about them, but not because they have something important to say about The Times In Which We Live, but just because they are big and dazzling and fancy (and that, perhaps, is what they say about The Times In Which We Live). What we're missing are the movies like Easy Rider or Annie Hall or Wall Street, movies that become Events because they touch a sociological nerve - and don't think I'm waxing nostalgic here; two of those three examples I've just given are films that I have frankly very little use for. But it is an odd thing, how the movies in that vein that get made (for they are, of course, still getting made) don't seem to hit with audiences anymore; critics sometimes, but in the past, oh, five years, has anything besides The Social Network made much of an impact while being A Story About Today?

(My suspicion is that part of the reason we don't see movies like this much anymore is because TV has mostly co-opted the Zeitgeist in the sense I mean; but the distressingly reasonable idea that Jersey Shore is the modern successor to Easy Rider and Midnight Cowboy and The Graduate makes me think that we're better off if Western culture just up and dies already).

These thoughts came to me while I was watching Bob & Carol & Ted & Alice, a film, like Easy Rider and Midnight Cowboy was released in 1969 (as was Hello, Dolly! - every cultural revolution has its pushback), and like those movies is so completely and utterly dated that it almost beggars description, and like those movies, became a talking point in '69 to a degree that it is literally inconceivable to imagine today: just try to envision Blue Valentine being a smash hit.

The film's reputation is such that, even 42 years later, there's still a good chance that you know what made it notorious back in the day (also that you could guess from the title): this is that movie where they have a foursome. And while that would remain a good way to market a picture today, it's worth pointing out how different things would have been back in 1969. This was only the second year after the dismantling of the Production Code, for starters, and thus the beginning of the age of nudity and frank sex talk in American cinema. It was also the end of the much-discussed Free Love era, and the script by Paul Mazursky & Larry Tucker (who'd contributed in a smaller way to the same movement with the previous year's I Love You, Alice B. Toklas!) plays unmistakably like an elegy for a movement that was clearly on its last legs, nor were they necessarily sad to see it go: it's at once more self-conscious and less romantic than e.g. Easy Rider, which seems aware in only a halting way that The Sixties are about to come to a crashing halt. The writers - Mazursky was also making his directorial debut with this picture, which history still regards as the high-point of his career (sorry, Moon over Parador) - strike a nifty balance between admiring the spirit and counter-cultural enthusiasm of its protagonists on the one hand, and recognising on the other hand that they're being a bit willfully stupid. I might sum up B&C&T&A by saying that it respects the mind-set of the counter-culture without being of the counter-culture; it is a film perpetually on the outside looking in.

And that's true from the very opening moments, a series of helicopter shots flying over a pristine stretch of California mountains, while the "Hallelujah" chorus from Handel's Messiah plays with agreeably straitlaced irony. Eventually, the camera closes in on The Institute, a place where the upper-middle-class goes to learn the hippie lifestyle - this means, in practice, naked people parading about - and though Mazursky and cinematographer Charles Lang choose to keep their camera mostly close to the characters, always on the same level and from the same perspective, that opening feeling that we are invading this space never quite goes away; even those same intimate close-ups are somewhat probing and invasivef, as if we're peering in real close to try to understand who these people are, that are not like us.

We're here to see two people in particular, and we know who they are because their names make up half the title: Bob Sanders (Robert Culp), a documentary filmmaker looking to learn about this strange place that teaches people how to be more in touch with what they feel, and his wife Carol (Natalie Wood). They're introduced as part of a circle in which all the participants are encouraged to say whatever they feel, and to own that, and so on; and by the time their trip to The Institute is over, Bob and Carol are deeply committed to the principals of free love and self-knowledge that they've learned there.

Thy are, in this way, set against their best friends, Ted (Elliott Gould) and Alice Henderson (Dyan Cannon), a couple like the Sanderses in most important ways: the same economic class, the same social circles, their children (a single boy in each case) are about the same age. Ted and Alice are impressed by their friends' newfound sense of harmony; and then they are vaguely disgusted by the degree to which they seem so eager to flaunt convention when Bob sleeps with a woman on a business trip to San Francisco, telling Carol about it, both of them seeming incomprehensibly nonchalant about the whole thing. Eventually this culminates in a trip to Las Vegas where, on the spur of the moment, the Hendersons decide to try their best to follow their friends' example, and the stage is set for an orgy, though as orgies go, it's not the most well-conceived or effortlessly performed. And this would probably count as a spoiler, if it wasn't the only thing that everybody who's ever heard of the film knows about it.

Anyway, the end point of the film is of decidedly less specific importance than the journey: this being 1969 and all, B&C&T&A is largely a character study, the kind of movie that was in vogue for a while and occasionally still crops up, in which the filmmaker trusts that if the parts are rich enough, and the actors skilled enough, we'll be enthralled just to watch fictional people working through their lives like you or. Mazursky was lucky, therefore, to get four such excellent performers working on his project, for the movie lives and dies based on their ability to quietly suggest the inner workings of a human mind; Wood is the best at this, particularly in the scene where she finds that she isn't actually jealous that Bob had an affair - and Culp's quickly-stifled disappointment at her non-reaction is the best moment in his performance - but each of the actors gets more than one chance to shine, and what would seem, to describe it, as a laundry list of scenes cranking along one after the other (here's where Ted clamps down on his envy for Bob, here's where Carol doesn't realise that she's acting superior to everybody, here's where Alice won't admit to her therapist that she enjoys sex), feels in the event like a coherent arc for each of the four, and all thanks solely to the investment of the actors; Gould and Cannon, the more obscure of the four when it was new, scored Oscar nominations, and not undeservedly as such things go.. It's all slightly acting exercise-ey, in spots, a bit too obvious who is trying to get what out of the other character, but for what amounts to a 105-minute visit with people discussing pop-sociology with one another, it ends up being far more entertaining and nuanced than you might imagine possible.

It's appealingly funny and somber by turns, though not especially robust in either of those directions, and its social satire is so very specific that it doesn't inherently hold much value other than as a time capsule. But those characters, and the intent way that the camera follows them, and the cross-cutting that pulls them apart and puts them back together (the last scene - I don't really want to spoil it - is an extraordinary study in how to use character eye-lines to create a mood and reinforce or dissolve the bonds between individuals), and especially the generally good-natured feeling of the thing - Mazursky's commitment to letting these characters make their mistakes without judging them for it - leaves the film touching and lovely even after its moment in the sun has long since past. It seems kind of hard to believe that in 1969, it was celebrated for its boundary-busting raciness; what has lasted isn't the fascination with celebrity skin, but the sensitive, sensible humanity underneath it all. It may be a slender little movie, but it's not a slight one.