Different structures for concepts of individuals, stuffs, and real kinds: One mama, more milk, and many mice

Although our concepts of “Mama,” “milk,” and “mice” have much in common, the suggestion that they are identical in structure in the mind of the prelinguistic child is mistaken. Even infants think about objects as different from substances and appreciate the distinction between kinds (e.g., mice) and individuals (e.g., Mama). Such cognitive capacities exist in other animals as well, and have important adaptive consequences.