As explosive as they seem on the surface, the Yeah Yeah Yeahs are also an ambitious, thoughtful band that keeps pushing the boundaries of their music. They moved from the rawness of their early EPs to the polished art-punk of their first full-length in just over two years, and this drive to keep topping themselves is what led to breakthroughs like Fever to Tell's gorgeous ballad, and hit single, "Maps." After taking three years to follow up Fever to Tell, and scrapping many of the songs that they came up with while on tour supporting that album, the Yeah Yeah Yeahs returned with Show Your Bones, the yin to their debut album's yang. While Fever to Tell and "Maps" dealt with falling in love (and being more than a little freaked out about it), Show Your Bones is a breakup album. It's funny -- if the Yeah Yeah Yeahs had made this album earlier in their career, Karen O's cutting lyrics and Nick Zinner's choppy guitars would've sliced the poor ex to pieces; after all, on "Bang," from their self-titled debut EP, they (hilariously) wrote off a lame one-night stand with "as a f*ck, son, you sucked." Show Your Bones, however, tries to go much deeper than that, with underwhelming results. It's only natural that using heartbreak as inspiration would lead to brooding, reflective songs, but the fiery, independent spirit that made the Yeah Yeah Yeahs so great initially is drained out of this album. Even on the rockers, Show Your Bones is too subdued, restrained, and overthought. The cryptic lead single "Gold Lion" (which sounds like a mash-up of Love and Rockets' "No New Tale to Tell" and Siouxsie and the Banshees' "Peek a Boo") is vague and a little plodding; though it eventually worms its way into listeners' heads, it's surprisingly unfocused, compared to the Yeah Yeah Yeahs' previous singles. "Phenomena," with its stomping riffs and fazer-like synths, is a more natural progression from the Fever to Tell style, but it still ends up feeling more indulgent than inventive. Aptly enough for the kind of album it is, Show Your Bones' softer songs are some of its strongest: "Dudley" sounds a little bit like Sonic Youth covering the nursery rhyme "Hush, Little Baby," while "Cheated Hearts" is a big, rousing ballad in the vein of "Maps." And, as on Fever to Tell, the band loosens up as Show Your Bones unfolds, coming up with some interesting songs in the process. "Mysteries" is a jealous cowpunk number that sounds tossed-off, but has more bite and fun in it than the rest of the album. On "Turn Into," the band takes this twangy sound and turns it sweet, resulting in one of their best songs yet. Unfortunately, though, too much of Show Your Bones just isn't that interesting, even if it was born from genuine heartache instead of sass and attitude. Actually, sass and attitude sound like the perfect antidote to heartache -- and, quite possibly, what ails the Yeah Yeah Yeahs.