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.)