Kids think with their brains cracked wide open; becoming an adult, I've decided, is only a slow sewing shut.

Picoult contrasts childhood’s unfiltered imagination with adulthood’s gradual self-censorship. “Brains cracked wide open” evokes a mind receptive to wonder, novelty, and unconventional connections—traits often encouraged in children and disciplined out of adults through schooling, work, and social norms. The metaphor of “slow sewing shut” suggests this narrowing happens incrementally: each rule learned, fear of judgment, or demand for practicality stitches the mind a little tighter. The line functions as both lament and warning, implying that maturity can mean losing cognitive openness rather than gaining wisdom, and inviting readers to preserve curiosity and creative risk-taking even as responsibilities accumulate.