"The COIN project aims at providing me with training experience in the Harvard Laboratory for Developmental Studies, in collaboration with innovative scholars studying infant cognition. I aim at acquiring expertise on conceptual development, further developing my experimental skills, gaining teaching and mentoring experience as a Teaching Assistant and returning to Europe to develop a pioneer field of research. I will investigate compositionality, a possibly human-specific computational ability that gives rise to the expressive power of human languages and thoughts. It consists in the ability to combine known concepts to create novel concepts. Thirty years of experimental work has shown that infants are equipped with core conceptual representations about objects, numbers and agency. Compositionality allows to go beyond core conceptual domains. However, it is still unknown whether pre-lexical infants can combine mental representations. As a case study, I ask whether young infants can compose representations of ‘same’ and ‘negation’ to generate the representation of ‘different’. Infants as young as 7-months can generalize a structure based on the concept ‘same’ (i.e. pairs of identical elements, AA), but no evidence were yet reported of the generalization of the concept ‘different’ (i.e. AB). I first seek to find the age at which infants can use both the concepts ‘same’ and ‘different’, asking whether the maturation of the language system correlates with the emergence of this ability. Second, I explore under what conditions younger infants might be induced to represent ‘different’, in order to further specify the representational and computational resources from which compositional logical structures are built in infancy. Specifically, I study the role of linguistic labels, which may allow infants to form summary mental symbols for what are previously analogical similarities. This transformation may be necessary for, or at least conductive to, compositionality."