Baby brain? Evidence for no objective cognitive differences between mothers, fathers and non-parents in the post-partum period.

Becoming a parent is a significant life transition, leading to extensive change and uncertainty in one's daily environment. Parenthood is often thought to have adverse consequences across multiple cognitive domains, such as memory, a phenomenon known colloquially as 'baby brain'. Evidence supporting an objective cognitive decline in the postpartum period is unconvincing, and it is unknown whether fathers experience similar changes in cognitive function. Here we examine cognitive differences in birthgiving mothers and non-birthgiving fathers up to two years postpartum. Four hundred participants (300 parents and 100 non-parents) completed a cognitive battery assessing executive function, working and episodic memory, processing speed and subjective memory. Parents showed similar performance to non-parent controls on all objective cognition measures, and we found evidence for no differences in cognitive performance between mothers and fathers, suggesting the absence of so-called "baby brain" effects. Significant group differences in subjective memory were driven by a self-promotion bias, where male non-fathers reported better subjective memory than all other groups. A commonly shown phenomenon in males, this self-promotion bias appeared to be lost in fathers, an effect driven by lack of sleep. Strikingly, there was no effect of time postpartum on any cognitive measure. Therefore, these results challenge the societal 'baby brain' stereotype, and provide a new foundation to support family units together irrespective of birth-giving status.