Modal concepts in infants and/or baboons
Language represents possible alternatives. Modal information, information about what could be or must be the case as opposed to what the state of the world really is, is lexicalized in natural languages, using words such as “could”, “should”, “might”, “possible”, etc. Do modal concepts exist in the absence of language? Recent research suggest that preschoolers and great apes struggle with these concepts (cf Leahy and Carey).