Women undergo profound psychological and cognitive shifts throughout their life course, and motherhood entails dramatic mind–body adjustments. Growing maternal responsibilities and evidence from social sciences suggest motherhood enhances cognitive functioning, but mothers typically claim otherwise. This article uses maternal life stories to reveal cultural schemas of mommy brain as told by mothers in the United States. Our findings illustrate what mommy brain is in practice and how cultural narratives promote associations between motherhood and diminished cognitive functioning. We found that interruptions, cognitive overload, and newfound anxieties were fundamental components in mothers’ mommy brain experiences. We believe that these factors, along with social isolation, play a salient role in self‐reported deficits in maternal cognition. Understandings of mommy brain must move beyond neurobiology and attention and memory studies and consider how interruptions, overload, and other subjective experiences shape our definitions and what we know about maternal cognition.