A Japanese scientist studied the brains of 50 people in their 20s and had them fill out a survey about their relationships with their parents. He found that people with neglectful or overbearing parents had less gray matter in the prefrontal cortex, which is associated with personality development. However, an Australian scientist critiqued the study for not accounting for other factors like socioeconomic status that could also influence brain development and cognitive tests. The effects found could be real but larger factors may be at play.