It's funny how catchy tunes get called "infectious," same as diseases, with the most infectious becoming a part of us.

Way back in the mid-2000s, Band of Horses emerged as purveyors of such songs. Their ‘Infinite Arms’ (2010) album became a part of listeners lives, and 'Funeral,' from their 2006 debut, was a particularly sweet virus. On subsequent efforts, they rehashed those highs without reinventing their sound, giving in to an underwhelming fit of inertia that ‘Mirage Rock’ has thankfully shifted.

Fittingly, the disc begins with the ooh-ooh-oohs of 'Knock Knock,' exemplifying the exuberance of the Band's best work. Giddy affirmations abound on the opener -- “Greatness achieved and darkness defeated,” for instance -- and 'Mirage Rock' gets its freshness from country-influenced melancholy, born of romance and youth lost. It lends these little indie-pop tunes a greater sense of gravity than those that came before.

Bandleader Brad Bridwell's lyrics are often gracefully direct, like on the heartsick 'Heart to Live,' where he turns refreshing, reflective phrases like, “I didn’t really need to suffer / still did it anyway." He ends, appropriately, with, “Guess what, you’re getting old / still gotta grow up,” an imperative you’d have to think he’s directing at himself.

The twang gets rough on 'Everything's Gonna Be Undone' -- filled with questions like, "How did you get wound so tight?" and pronouncements like, "You couldn't take another broken heart" -- and the Neil Young-like 'Long Vows,' a slow strum of singing saws and melancholy. Although they do the sad songs well, they can overdo them. The unraveled spoken-word album-closer 'Heartbreak on the 101' is a weepy, wan track that fails to fulfill its heart-tugging ambitions.

Even when peppy, this is a nostalgic record. Sounding just like its name suggests, ‘Slow Cruel Hands of Time’ comes complete with tours of high school and neighborhood and home, memories that show how the “slow cruel hands of time turning you back into a child.” On ‘A Little Bibical,’ Bridwell notes, “I’m old enough to see / I’m not the only one.” The band glimmers in ‘Shut-in Tourist,’a warm breeze of jangly pop, sketching urban scenes and travels abroad.

A bit of R.E.M. drive pushes ‘Feud,’ a throwback to older tracks like ‘Laredo,' though with the chorus of, “I want you to fail," it lacks the positivity of earlier anthems. The standout here is the rollicking sucrose-soaked ‘Electric Music' -- three and a half minutes of hearts and highways, with Birdwell chirping, “This is what it does, traveling the opening road.” It's as endearing as anything they've put out.

The Horses have always been a familiar kind of band, their comfy-sweater choruses matching those of their indie-pop peers. With 'Mirage Rock,' though, by reaching further  into the American songwriting tradition, they have reinvented themselves.