Exploring size-action and number-action associations in infancy

In the last decades, a growing body of research has assessed the link between numerical and action processing. However, this relationship has not been widely explored in the early stages of development. In this study, we aimed to investigate the number-action mapping during infancy with a novel action and to extend previous research by examining both size-action and quantity-action mappings. In the context of our study, 'size' is related to the perceptual attribute of how big or small an object appears and 'quantities' are connected to the numerical aspect, representing the number of items in a set. Using the habituation technique, 7-month-old infants were presented with videos of a character performing mouth openings directed towards objects of different sizes (Experiment 1; N = 40; 14 females) or quantities (Experiment 2; N = 40; 18 females). The findings suggest that infants are sensitive to the congruency of the pairings, highlighting the early presence of both number-action and size-action mappings. • The study investigates size-action and number-action link in infancy, implementing a novel action (i.e., mouth opening). • In two experiments, 7-month-old infants were tested using the habituation technique. • We found that infants are sensitive to the congruency of the pairings. • We support the idea of early presence of magnitudes-action mappings in infancy.