Research support - Field et al
-Gathered 36 infants divided them into 3 groups: group 1 is infants interacting with PGC mothers, group 2 infants interacting with PCG fathers and group 3 infants interacting with their secondary caregiver fathers.
-Found that fathers who were not PCG's engaged in game playing.
-The PCG's of both genders showed smiling, imitation of facial expressions and and high pitched vocalisations.
-Suggests sex of parental figure doesn't matter but its the quality of the interaction.