“Psychology of Jazz”? That sounds more like a doctoral thesis – maybe even a “science for artists” course in college – than a recording project.

In fact, more than a few treatises along those lines have popped up over the years. And in a sense, Psychology of Jazz is indeed a sort of thesis – except that it swings instead of plods; the footnotes come in the form of grace notes; and the oral arguments are all sung, delightfully at that. There’s no bibliography: subtext and context are bound up in Debby Yeager’s sunny/cloudy timbre, the cool insights of her phrasing, and the effective, affecting arrangements she’s crafted with pianist Stu Goldberg. She has an abiding interest in what makes people tick, and she’s become a keen observer of the human condition. Yeager recognizes the darkness as well as the light in the music she sings, and her insights enrich even familiar songs, leading us deeper into material we may already know.

You don’t even need a couch.

Take the early 1960s tune “Visit Me,” written from the perspective of a bohemian Romeo who’s already decided “my place, not yours.” It seemed harmless when it first appeared, but the #MeToo generation might view it an invitation to seduction. Yeager tackles that possibility head-on and claims it as her own: she offers the lyric from a female perspective, in the spirit of turned tables and equal opportunity. Doug Webb’s serpentine soprano sax solo supplies a perfect counterpoint.

An even better example comes on “Devil May Care,” written and recorded by Bob Dorough in the mid-50s. I suspect most of us hear this as a theme song for some Beat Generation vagabond: a buoyant paean to the carefree life. For Yeager, it means more. She first heard it in as a preschooler in 1957 as it breezed in from a neighbor’s hi-fi on open-window summer days, and it became a touchstone – as did Dorough’s flighty vocal flint – during tough times in her childhood. This was long before she could appreciate the lyric, and long before she’d befriend Dorough himself (enlisting him to perform on her debut album Mood Swing.) So for Yeager, “Devil May Care” has become a song that affirms her own strength and resilience against long odds; those characteristics are mirrored in the ruby cello tones that shade the introduction, and in the chaotic swirl of instruments toward the end.

Certainly, not every tune here comes freighted with hidden meaning. (Freud begone!) The English lyric to “Suddenly” – a Brazilian melody loaded with saudade (that nation’s trademark mix of joy and longing) – carries enough psychological import as is, in the recognition that most heartbreaks eventually heal. And the message of measured optimism contained in “Tomorrow’s Another Day” needs no extraneous analysis. Yeager sings it with an understated wisdom that highlights its place as an “antidote to despair,” as she puts it. (The melody started out as a 19th -century Swedish folk song; after the bop generation transformed it into the jazz standard “Dear Old Stockholm,” vocalist King Pleasure provided the words and a new title.)

But then there’s “I Could Write a Book.” At face value it’s an unadorned statement of amatory admiration – part of the reason it has become a hallowed standard – and Yeager sings it accordingly, without apparent irony or subterfuge. But in the 1940 musical Pal Joey, where this song first appeared, “I Could Write a Book” actually underscores the title character’s duplicitous and manipulative nature – his willingness to say anything and even feign sincerity in pursuit of his goals. That fact is not lost on Yeager (who admits to a certain fascination with Joey’s ability to mystify and persuade); she may not emphasize that knowledge here, but it’s enough that she had it in mind when she included the song.

The implications of this material seep in almost without you noticing, because Yeager is first and foremost a charming vocalist, beckoning the listener to lean in close and appreciate her musicianship on its own merits. She sings with a mix of confidence and vulnerability, in a pearly alto that caresses each melody; she improvises sparingly, allowing her unforced swing to carry the up-tempo tunes and gently animate the ballads. And her hand-picked band, sporting top-notch soloists and an unimpeachable rhythm section, has no trouble earning the spotlight when it shines on them. Music shouldn’t depend on its backstory to convey nuance and beauty, and with artists like this, there’s no need to do so.

They help make each track a distinctive, carefully wrought cameo highlighted by Yeager’s imperturbable approach. It’s a style that fits squarely in the lineage of the iconic vocalists who helped shape the Cool Jazz movement of the 1950s – singers like June Christy and Chris Connor, Dorough and trumpeter-vocalist Chet Baker. Yeager directly acknowledges Baker’s influence in “Hear Me Blow,” in which she’s put words to his brief but grand 1958 solo on the little-known Rodgers & Hart gem, “Do It the Hard Way”; it might (and should) remind you of similar forays by Annie Ross. And like Ross, Yeager tells her stories without bombast: less sound and less fury than you’ll hear from a lot of singers, and a good deal more significance for just that reason.

Speaking of “reason,” pay special attention to “Without Rhyme or Reason,” composed by Dorough, with words by the remarkable Fran Landesman – a song redolent of its time (the mid-60s), which ought to sound dated but which has remained charismatic nonetheless. Ron Stout pours a perfect solo from his flugelhorn, and Goldberg, as he does throughout the album, balances pure technique with melodic flow. It’s the longest performance on the disc,
and it encapsulates the many underlying currents contained in this album. It intertwines romance and knowledge, threads of clear-eyed wonder and hardened filaments of experience; the cello lends a dolorous contrast to Yeager’s feathery phrasing.

It’s lovely and complicated, and if you have a better description of the human condition – the premise for Yeager’s music, and the premise for this album – please send that along.

NEIL TESSER