Rock has always lionized the raucous, aggressive young Turks who want to take a walk on the wild side, but there’s also a flip side to that image: quiet young men with high voices and deep emotions who sing not of rebellion but of surrender.

These sensitive, introspective male pop stars — let’s call them SIMPS for short — had their heyday in the post-hippie era, when James Taylor, Jackson Browne, Dan Fogelberg and Dan Hill ruled the charts. They strummed acoustic guitars, furrowed their brows expressively, and sang soulfully about heartbreak, loneliness and the burden of being them. In the 1970s, SIMPS were everywhere, but faded into irrelevance over the next decade, thanks to the combined ascendance of power ballads, punk rock, and pretty boys like Duran Duran, George Michael and Prince.

But if it’s true, as Paul Simon sang, that “every generation throws a hero up the pop charts,” it’s just as true that every generation gets the SIMPS it deserves. Including this one.

Right now, the hottest SIMP on the charts is probably Ed Sheeran, a tousle-headed, 21-year old Englishman whose dreamy, whisper-voiced debut album, +, was in the Canadian Top 10 for a month. When his first North American tour was announced last month, shows in Toronto and Vancouver sold out so quickly that both were moved to bigger venues (Molson Amphitheatre in Toronto, Sept. 17, and Queen Elizabeth Theatre in Vancouver, Oct. 4).

Then there’s Gotye, the Belgian-born Australian whose mournful breakup single, Somebody That I Used to Know, has been on the charts so long it may well have bought a condo there. And let’s not forget strummy surfer Jack Johnson, whose 2010 album To the Sea topped the charts in both Canada and the U.S., or James Blunt, whose sweet-voiced hymn of adoration, You’re Beautiful, was all but unavoidable on radio in 2006.

They don’t quite sound like Taylor or Browne, but the formula remains the same: high, quiet voices; soft, gentle rhythms; deep, painful emotions. Nor are they all creatures of the Top 40. Generation Y has produced a passel of alt-SIMPS, from the poetic falsetto and soft-focus soundscape of Justin Vernon’s Bon Iver albums, to the quivering tenor and kaleidoscopic arrangements of Zach Condon and Beirut, to the naked emotion and stripped-down sound of Royal Wood.

And who knows? If Drake’s murmured, brooding Marvins Room is any indicator, we may be on the verge of having hip-hop SIMPS.

But then, the whole sensitive male singer thing was never about musical style so much as it was about emotional expressiveness, the ability of a singer to project openness and vulnerability in a way that allows audiences both to share his pain and wish they could ease it.

In that sense, the first great SIMP was probably the young Frank Sinatra. A skinny young man with a rich, expressive voice and deeply expressive eyes, he was an object of fascination and desire for countless bobby-soxers, who thronged theatres wherever he performed. James Kaplan, in his biography, Frank Sinatra: The Voice, rhymes off the attributes that left young women in thrall: “[the] catch in his voice… the tousled spit curl on his forehead … the help-me look in his bright blue eyes….” These qualities, writes Kaplan, “set them off like dynamite.”

The teen idols of the late 1950s — Fabian, Frankie Avalon, Bobby Rydell — were to some extent an attempt to reframe Sinatra’s allure in rock-’n’-roll terms. But because rock’s appeal derived more from self-definition than vocal style, those prepackaged pop stars lacked the resonance of the Beatles or Bob Dylan.

That may be why the rock-era SIMPS are so closely associated with the singer/songwriter boom of the 1970s. Not that all of the era’s singer/songwriters qualified; certainly, no one would ever think of Leonard Cohen as a SIMP, and even though Paul Simon’s solo work was certainly introspective, it was never as self-involved or self-satisfied as Fogelberg’s, Taylor’s or Browne’s.

Backlash was inevitable, and it was the critic Lester Bangs who put it most bluntly. In an essay entitled James Taylor Marked for Death, Bangs fumed that if he heard, “one more Jesus-walking-the-girls-and-boys-down-a-Carolina-path-while-the-dilemma-of-existence-crashes-down-like-a-slab-of-hod-on-J.T’s-shoulders song,” he would personally (and literally) eviscerate the singer. Anyone else would have simply turned off the radio, and eventually, everyone did.

But the need for the emotional resonance only a SIMP can provide did not disappear along with the seventies troubadours. And what made it commercially viable again was rhythm, thanks to the work of two unlikely pioneers: David Gray, and Howie Day.

Manchester-born but London-based, Gray first surfaced in the mid-nineties as a cerebral, slightly wonky singer/songwriter, and broke through in 2000 with White Ladder, a gently burbling blend of acoustic guitar and synth loops he recorded in his home studio. By fusing the low-key energy of ambient dance music to the hushed intimacy of confessional songwriting, Gray single-handedly breathed new life into the SIMP aesthetic (and set the template for Gotye’s chart career).

Day, from Bangor, Me., started out as an acoustic neo-folkie, but eventually augmented his Takamine guitar with a loop station, a pedal-based digital sampler that allowed him to layer repeating sounds until he became a virtual one-man band. Not only did this help him save on sidemen, it also opened a bridge to the world of hip hop, loops being the basic rhythmic unit of contemporary rap.

That, in turn, leads us to Sheeran, a SIMP who claims to have been equally influenced by Jay-Z, James Morrison and Damien Rice, a combination born out by the wistful melodies and insistent rhythms of +. Sheeran not only uses a loop station but sings about it (on the song Wayfaring Stranger); he also raps, and if his flow is more One Week than 99 Problems, it perfectly suits his sound and image.