Until her suicide in 1971, photographer Diane Arbus made a career out of documenting "freaks." Her archive is a hall of fame and mirrors, housing giants, dominatrixes, twins and triplets, and one-of-a-kind oddities like a woman with a baby monkey swaddled like a child. Even regular people became freakish behind her lens.

In An Emergency in Slow Motion: The Inner Life of Diane Arbus, William Todd Schultz, a psychology professor at Pacific University, pre-sents a psychobiography of Arbus—a novel blend of character study, art criticism, and cold case. He seeks the motives behind her freak fixation, to shed light on both the art and the artist. Photography, he argues, was how she let out her demons, but never fully released them, accounting for just one of several factors in her demise.

Examining a life in this way has its perks, especially for those new to Arbus. Schultz forgoes completeness and jumps straight to her most formative experiences; it's a circuit map, not a blueprint. Thankfully, Schultz doesn't try to draw a straight line between Arbus' childhood and her life as an artist. She suffered typical parents for a rich girl turned creative: Her father was a distant department store owner and grinning philanderer whose affinity for Diane might have gone too far; her mother a depressed "zombie;" her brother was an ally in the mess, but this may have led to sexual experimentation and subsequent shame.

Schultz nimbly accounts for family's influence on Arbus without crowding out the role of her own experiences and character. Susan Sontag wrote that "Arbus' interest in freaks expresses a desire to violate her own innocence, to undermine her sense of being privileged, to vent her frustration at being safe." Schultz strengthens this point by locating the pattern's inception: As a Depression-era child, Arbus' bubble of privilege burst when she stumbled upon a shantytown in Central Park. According to Schultz, "The shantytown visit is emblematic, encapsulating the art's motive. She was born into shadow-immunizing wealth that she spent her life painting black."

While Arbus' choice of subject may have been the product of her upbringing, Schultz believes she was born an artist. Although biographical evidence here tells the story—Arbus photographed compulsively, even in her dreams—Schultz layers on personality theory to make his point. The classifications read more like a filing system than an analysis—she's high in "openness," or "O," which correlates to "sensation seeking" (SS) and "experience seeking." It's one of very few places where his psychological dissection slows down our understanding of Arbus.

On the other hand, Schultz gains momentum when aimed at Arbus' mysterious "genius." He judges emphatically. "Nothing got Arbus going like secrets," he says, "her own and her subjects'." Elsewhere, hunger for experience reigns. He declares, "What Arbus was about, maybe more than anything else, was just that. Experience... It was the source of her adventurousness, her explorer mentality." It's difficult to resolve these motivations, and even harder to know if Arbus acted consciously or compulsively.

Yet these limitations speak more to the nature of the material than to Schultz's treatment of it. A scrupulous academic, Schultz doesn't make declarations where the evidence doesn't allow. Though he forcefully identifies patterns, he sometimes stops short of, or hovers around, decisive conclusions. He finds "truth, but as direction not destination, more a pathway than a location. We never know everything," he concludes, "but we don't know nothing." Psychology may be a softer science than the rest of them, but An Emergency in Slow Motion is undoubtedly a successful experiment.