Assessing a continuum of lexical-semantic knowledge in the second year of life: A multimodal approach

•Behavioral dissociations reported in a 2AFC word comprehension task at 22 months.•Incorrect haptic responses in this task appear to represent partial word knowledge.•Young children leverage partial knowledge for future word recognition.•Visual RT and haptic response likely tap different levels of word knowledge.

Behavioral dissociations in young children's visual and haptic responses have been taken as evidence that word knowledge is not all-or-none but instead exists on a continuum from absence of knowledge, to partial knowledge, to robust knowledge. This longitudinal study tested a group of 16- to 18-month-olds, 6 months after their initial visit, to replicate results of partial understanding as shown by visual-haptic dissociations and to determine whether partial knowledge of word-referent relations can be leveraged for future word recognition. Results show that, like 16-month-olds, 22-month-olds demonstrate behavioral dissociations exhibited by rapid visual reaction times to a named referent but incorrect haptic responses. Furthermore, results suggest that partial word knowledge at one time predicts the degree to which that word will be understood in the future.