Dr. Dog has made a huge mistake. The band’s highly anticipated third album, “We All Belong,” was uniquely positioned to introduce a wider audience to Dr. Dog’s riotous late-’60s sound. But the album is plagued by slapdash songwriting and indulgent instrumentation. As disposable, Beatles-esque pop, the album excels. Yet its lack of substance in the face of the attention Dr. Dog stood to garner proves inopportune, if not frankly wasteful. “We All Belong” may be fun, but it’s disappointingly trivial.

Two years ago Dr. Dog was just beginning to make waves outside their hometown of West Philly. Having mastered the faux-amateurism currently in vogue in indie circles, the band began to develop a devoted live following thanks to the spirited performances and expressive playing that reflected countless hours of rehearsal. Their sophomore album “Easy Beat” put that joyous live show to tape (hoots, hollers and all). Deceptively rough-and-tumble songs disguised sharp songwriting. The influence of Lennon/McCartney et al remained secondary, albeit conspicuous. Then, thanks to headliner fiat or else overzealous management (for which, in either case, the band ought to be immensely thankful), Dr. Dog opened first for Clap Your Hands Say Yeah and the National (each riding the waves of their own successful 2005 releases), and then for the Raconteurs. The band spent much of 2006 honing their skills and their songs on the road all over the United States.

All this to bring us “We All Belong.” What a shame, then, that so many of the songs fall flat. The band’s sloppiness seems no longer to be put-on. The late-’60s incidental touches have become the primary pieces from which the songs are constructed, piecemeal. Each track is an empty space into which to cram more “Pet Sounds” sleigh bells, “Music from Big Pink” organs and “Let It Be” ad-libs — all of which, for example, can be found on the first single “My Old Ways.” This ’60s-to-excess strategy pervades the album, from the eight (eight!) times that the band counts off “one, two, one two three four” at the beginning of “The Girl” to the singalong chorus in “Old News,” when all the instruments cut out, and the lead singer implores “Well, let me hear you now,” a mere 82 seconds into an under-two-minute song.

This is not to say that Dr. Dog has, in a single moment, become talentless — they have merely become uninspired, which is nowhere more evident than in their incredibly corny lyrics. The prize for worst line certainly goes to “Well, you’re looking for the lightswitch … Click! it’s on,” from “Worst Trip,” with the mid-line pause presumably indicating the time spent looking for the switch. But there are plenty of other viable contenders for that prize. (Not to mention the absurdity of a band named Dr. Dog singing about a dog that’s “barking out back/ He thinks he’s in the band,” as they do in “Alaska.”)

The album’s best song, “Ain’t It Strange,” is also its sparest. Its constituent parts (including, yes, sleigh bells) slowly and organically build rather than being piled on, and though it falls just short of the songs on “Easy Beat,” “Ain’t it Strange” hearkens back to those eight-tracked gems. For its part, Dr. Dog seems at least vaguely aware of the extent to which “Ain’t It Strange” outperforms the rest of “We All Belong” — evidenced by its position as the leadoff track of both their 2006 EP “Takers and Leavers” and of what would be side B of “We All Belong” were it released on vinyl (the latter at least a subconscious consideration for a band as attuned to late-Sixties rock as this quintet).

Despite this apparent awareness of their album’s strengths and weaknesses, the band, for whatever reason, signed off on the album, warts and all. And all the sought-after supporting tour slots in the world won’t make it any better. As a different band’s first record, “We All Belong” would probably gain some fans enthused by the sound and who hope for a more original follow-up. But for Dr. Dog, who have shown themselves capable of much more in the past, the record is a frustrating misstep.