 There are many ways to try to draw the further distinction between perceptual maturation and perceptual learning. Some such ways are found in the debate between nativism and empiricism (see Samet 2008 and Markie 2015) and specifically in the difference between innate and acquired characteristics (see Griffiths 2009 and Cowie 2016). One potential criterion here is that cases of perceptual maturation involve perceptual abilities that are typical of the species, while cases of perceptual learning involve perceptual abilities that are not typical of the species. This criterion seems to get it right for some instances of perceptual learning, say, for those involved in birdwatching. After all, the perceptual abilities acquired in birdwatching are unique to birdwatchers, not typical of the entire human species. However, the criterion seems to get it wrong for other, more universal, instances of perceptual learning. For instance, since human faces are both ubiquitous and important to humans, the perceptual learning involved in face perception is in fact typical of the species.