Objectives: The study aimed to discern whether caregiver culture influenced infant pain expression at the 12-month immunization through caregiver behaviours. A moderated mediation model was developed to examine how caregiver behaviours mediate the relationship between caregiver heritage culture and infant pain. Caregiver North American acculturation was introduced as a moderator to examine how the model was impacted when heritage cultural identification and North American acculturation were congruent or incongruent. Methods: Infants (N = 393) with immunization data at 12 months of age were examined. Caregiver behaviour measures were emotional availability rating and proximal soothing behaviour frequency. North American acculturation was measured with a numeric rating scale. Heritage culture was a novel index created from an objectively derived, ‘individualism’ rating assigned to the caregiver’s self-reported heritage culture and the caregiver’s self-reported identification with their heritage culture (i.e., the Heritage Culture Identification and Individualism Index [HCIII]). Two moderated mediation models were estimated, examining infant pain at 1 and 2 minutes post-needle. Results: Regardless, North American acculturation, caregivers who had higher identification with heritage cultures that were highly individualistic (higher HCIII) tended to show greater emotional availability, which in turn predicted decreased infant pain at both 1 and 2 minutes post-needle. Next, caregivers who had higher HCIII scores showed more proximal soothing behaviours, which in turn predicted higher infant pain at 1 minute. Conclusion: The present findings further our understanding of the mechanism by which caregiver culture (and identification with that culture) impacts infant acute pain
