Take a story's temperature by studying its tone. Is it hopeful? Cynical? Snarky? Playful?
Objective, Ironic
Alice Walker slips inside the heads of her characters, allowing them to do most of the talking.
So when we're in Meridian's head, we look at the world through her eyes. Same for Truman and Lynne. Given the controversial subject matter, it would be easy for Walker to let her own voice overwhelm her characters' voices, but she strikes the perfect balance here.
While it might seem simple, Walker uses this technique to great ironic effect. There are countless instances when we can tell that the characters perceive the world a lot differently than Walker. For example, Truman's assertion that "b****es are dispensable" opens our eyes to his misogyny rather than making us empathize with him, as he might expect (2.17.29). We feel similarly when Lynne fears that "the sight of her naked would turn [her black friends] into savages" (2.22.36). By exposing these contradictory ideas (and allowing them to exist on their own), Walker is able to get at the harsh truths that lie beneath the surface of everyday life.