Cognition researchers should beware assuming that people's mental faculties have finished maturing when they reach adulthood. So say Laura Germine and colleagues, whose new study shows that face learning ability continues to improve until people reach their early thirties. Although vocabulary and other forms of acquired knowledge grow throughout the life course, it's generally accepted that the speed and efficiency of the cognitive faculties peaks in the early twenties before starting a steady decline. This study challenges that assumption.