Six experiments elucidate this issue. Infants look at this named image-but only if it depicts an object reported by their parents to be in their vocabulary. This result validates preferential looking and parental report.
Subsequent experiments investigate word learning.
Experiment 6 replicates Experiment 3 and further shows that the learning in that experiment is disrupted by a change in the gender of the speaker between training and testing. It is concluded that word learning in infancy may be associative in nature. It is, however, admitted that this is not the only interpretation of the data.