Trainor , et al. ( 2003 ) hypothesized that these results indicated that responses from infants less than four months of age are produced by subcortical auditory structures , .
With older infants responses tend to originate in the higher cortical structures .
Trainor , et al. ( 2003 ) hypothesized that these results indicated that responses from infants less than four months of age are produced by subcortical auditory structures , whereas with older infants responses tend to originate in the higher cortical structures .