Second, they were designed to examine the origins and developmental timetable for the emergence of this ability. The literature suggests that infants as young as 7 months of age are able to encode correlations among two features that are presented simultaneously (Younger & Cohen, 1986), but it remains to be seen whether infants at this age are also able to associate features that are not presented together. Third, the experiments were designed to investigate the mental representation that infants form when they engage in second-order correlation learning.