What am I supposed to be looking at? Controls and measures in inter-modal preferential looking

Intermodal preferential looking (IMPL) is widely used in experimental studies of infant development, especially language development. Control measures vary, and it is not clear how these affect findings. We examined effects of parental awareness of stimuli. Infants (17-19 months) looked at paired pictures, one name-known and one name-unknown, each assigned target status in 50 % of trials. Infants looked longer at a name-known than a name-unknown target, regardless of parents' awareness. When parents were aware, looking to a name-unknown target increased over a paired name-known non-target. There is evidence that infants' looking at pictures in this paradigm is not due to direct matching of targets to novel names, but is influenced by additional cues present, in a way that could alter the conclusions of studies of infant word learning and other aspects of infant learning. Implications of these findings are discussed, emphasising replicability and theoretical conclusions drawn from studies using this method.