Ihaven’t thought about it,” says J Mascis, when being asked about his band, the alt-rock pioneers Dinosaur Jr, turning 40 this year. “I just put one foot in front of the other.” The response is akin to a verbal shrug, which is a common reply for Mascis. A lot has been written about his communicative reticence over the years and I can confirm every adjective used about him – laconic, phlegmatic, apathetic, listless – is accurate. Still, in between the monosyllabic answers, he is also quietly funny. And if you lean into these moments, rather than allow yourself to be choked by the suffocating silences that fill so many parts of the conversation, Mascis can actually be a hoot. Relatively speaking. Just take his concept of having fun. “People always ask me after a show: ‘Did you have fun?’ and that drives me crazy,” he says. “I mean, maybe, but probably not. Fun seems to be the driving force for a lot of people but I’m not bothered about it.” Or his response to being asked how his hearing is after decades of noise being spewed into his ears. “I dunno,” he says. No tinnitus? “Oh yeah, I have that.” Is it manageable? “It is if you don’t listen to it.” However, the loudest and most obvious case for not caring about whether Mascis talks a lot is his music. The 58-year-old is a guitar player so distinct, expressive and lyrical – gliding gracefully between deft melody and squealing cacophony – that his craft speaks more for him than words ever could. And on his fourth solo studio album, What Do We Do Now, Mascis has created some of his best work outside Dinosaur Jr. His gently emotive voice, halfway between a croon and a croak, carries a set of acoustic-leaning folk-rock songs that are punctuated by Mascis’s unfurling guitar solos and some pummelling percussion. In the video for Can’t Believe We’re Here, a number of famous fans, including Idles and the comedians Fred Armisen, David Cross and Eugene Mirman all sing along in what feels like a timely tribute to four decades of Mascis’s inimitable work. “He just keeps coming out with really good songs all the time,” says My Bloody Valentine’s Kevin Shields, another alternative guitar hero. “I’ve been a fan since 1987 and have heard pretty much everything he’s ever done.” The moment that made Shields into such a fan was Dinosaur Jr’s You’re Living All Over Me. “It was a real ‘wow’ moment,” he says. “Like, what is this? It was dynamic, melodic, aggressive, extreme, original and unbound by dogma – going in all different directions seamlessly. Nobody else was doing anything like that.” Prior to blowing minds in Dinosaur Jr, Mascis grew up in Amherst, Massachusetts, as a “weird kid”. A music obsessive, he would build a wall of furniture around his bed to listen to records by the likes of the Beach Boys, Deep Purple and Neil Young. When punk hit town, he formed a teenage hardcore band called Deep Wound – his mum even knitted him a sweater with their name on it. Obsessed with Nick Cave’s the Birthday Party, Mascis would break eggs into his hair to try to emulate the singer’s wild crow’s nest haircut. He formed Dinosaur – the Jr was added later due to legal action from another band called Dinosaurs – in 1984, with Lou Barlow and Patrick “Murph” Murphy. The aim was to make “ear-bleeding country” music and the volume they played at quickly got them banned from venues. This ferocious assault would later morph into a sound that blurred lines between alt-rock, grunge and a more melodic and jangly sound coming out of the college radio boom. Their influence in the world of alternative music is seismic, inspiring everyone from Radiohead to Blur, with Kurt Cobain even inviting Mascis to join a pre-fame Nirvana (he passed). Despite Mascis’s withdrawn approach and a daily routine that mirrors a stoned teenager on school holidays (“I get up late, ride my bike and then mess around with guitar or drums”), to call him a slacker would be a gross misrepresentation. In reality, he is a prolific artist who has released more than 20 albums in various genres and guises over the years. He says making solo albums allows him to go to places he can’t with his regular band. “With Dino, I’m writing with them in mind, so it’s limiting,” he says. “I’m thinking about the limitations of the band, but I don’t think about that with solo stuff.” If that sounds like a slight dig at his bandmates not being as elevated musicians as Mascis – who usually plays all the instruments on his solo records – then that would hardly be surprising. Despite appearing somewhat milquetoast, Mascis has been accused in the past of being controlling and overcritical. Both Barlow and Murphy have had prolonged stints outside Dinosaur Jr due to fallings out before getting back together as a three-piece in the mid-2000s. Despite assurances from Mascis that “we’ve figured out how to deal with each other and we communicate better now”, you still get a sense of lingering tensions and unresolved frustrations. Mascis feels the band have never quite managed to lock back into the groove – both sonically and interpersonally – of 1987’s second album You’re Living All Over Me. “That was just a moment in time when things were coming together and our sound was getting more defined,” he says. “I don’t feel like we’ve surpassed that at all. We were getting along then, too. I guess mainly because Lou didn’t talk at that point so there was nothing to not get along about.” So it makes sense that Mascis would choose to savour memories of a time of less drama, and one loaded with optimism and naivety. There’s a beautiful moment in Michael Azerrad’s book about 80s underground rock, Our Band Could Be Your Life, in which Dinosaur Jr are fresh from touring with their heroes, Sonic Youth, for the first time and are so overcome with joy that both Mascis and Barlow are almost brought to tears in the tour van. It also marked a period in which the band hit their only real milestone. “Our goal in forming was to be on SST records,” says Mascis of the indie label home to Black Flag, Meat Puppets and Hüsker Dü. You’re Living All Over Me was Dinosaur Jr’s sole release on the label. “After that, everything was weird because we’d already achieved our goal. It’s like: where do you go from there? You’re just kind of floating and that’s been the rest of my career.” Dinosaur Jr continued to have great success, artistically and commercially, throughout the 90s, so does Mascis really feel like that? “I guess,” he says – another verbal shrug – before exposing a little vulnerability. “It feels more existential now. Like, does anyone listen to albums any more? Do they have enough of my albums? Is there any point to making an album? You just do it anyway but it’s weird because you don’t know if anyone will hear it.” Despite having a genuinely excellent new solo record, Mascis admits it can be harder to break new ground when you have four decades’ worth of music made by someone with such a distinctive style. “I wish there was an app that told you what song [of yours] you’re ripping off with your new song,” he says, before talking himself out of his new invention. “Although a lot of times ignorance is bliss and you just don’t know until someone tells you later.” As we wrap up, it is clear that hitting the big 4-0 as a band and having fun is not of any significant interest to Mascis, but does he still feed off the raw power he can create musically? “I still get a kick out of making a racket,” he says with a flicker of positivity, before that understated dry humour seeps back in again. “I mean, I don’t have many other interests.”