Remembering when Words are Mutually Exclusive

During the second year of life, infants develop a ‘mutual exclusivity’ bias to attach novel object labels to novel, nameunknown objects, rather than familiar, name-known objects (Markman, 1989). In an intermodal preferential looking experiment with 19.5and 22.5-month-old infants, stimulus repetition was critical for observing mutual exclusivity. On the first occasion that a novel label was presented with a familiar and novel object, looking behaviour was unsystematic. Upon re-exposure to the same stimuli, 22.5month-olds looked preferentially at the novel object prior to the re-presentation of the novel label. These findings suggest a powerful memory mechanism for novel labels and objects, enabling mutual exclusivity to emerge across repeated exposures to potential referents.