Figure 12.3: Interaction between genes and environment Security of attachments to their mothers was positively correlated with the sensitivity of maternal care for most infants, but not for those with the // genotype, who showed secure attachment regardless of quality of care. Attachment security was scored numerically, based on each infant’s behavior in the strange situation, and the scores were standardized, such that 0 is the average overall of the infants combined. (Standardized scores are explained in the Statistical Appendix.) The upward slope for the ss/sl infants is statistically significant; the slight downward slope for the // infants is not significant.

(Based on data from Barry et al., 2008.)