Supplemental Materials

Supplemental Materials Genetic Moderation of Stability in Attachment Security From Early Childhood to Age 18 Years: A Replication Study by K. L. Raby et al., 2015, Developmental Psychology http://dx.doi.org/10.1037/dev0000053

Detailed results of the focal analyses

The tables below contain the results of the analyses involving the composite measure of early childhood attachment security and OXTR SNPs as predictors of coherence of mind during the AAI (Tables A1 and A2), dismissing states of mind (Tables A3 and A4), and preoccupied states of mind (Tables A5 and A6). Table A1 Predicting Coherence of Mind During the Adult Attachment Interview From Early Childhood

Attachment Security and OXTR rs53576 2 B SE β p R change p Step 1 .05 <.01 Intercept 4.68 0.15 <.01 Ethnicity 0.52 0.15 .15 <.01 Early childhood attachment security (ECAS) 0.63 0.20 .13 <.01 OXTR rs53576 -0.07 0.12 -.03 .54 Step 2 .00 .18 Intercept 4.68 0.15 <.01 Ethnicity 0.52 0.15 .15 <.01 Early childhood attachment security (ECAS) 0.30 0.32 .06 .34 OXTR rs53576 -0.07 0.12 -.03 .55 ECAS × rs53576 0.55 0.41 .09 .18 Note: Ethnicity was coded: 1 = White/non-Hispanic, 0 = otherwise. ECAS = early childhood attachment security. OXTR rs53576 was coded: G/G = 0, A/A or A/G = 1. n = 564. Table A2 Predicting Coherence of Mind During the Adult Attachment Interview From Early Childhood

Attachment Security and OXTR rs2254298 2 B SE β p R change p Step 1 .05 <.01 Intercept 4.68 0.14 <.01 Ethnicity 0.51 0.15 .15 <.01 Early childhood attachment security (ECAS) 0.65 0.20 .14 <.01 OXTR rs2254298 -0.22 0.14 -.07 .12 Step 2 .00 .16 Intercept 4.68 0.14 <.01 Ethnicity 0.51 0.15 .15 <.01 Early childhood attachment security (ECAS) 0.51 0.22 .11 .02 OXTR rs2254298 -0.22 0.14 -.07 .11 ECAS × rs2254298 0.69 0.49 .07 .16 Note: Ethnicity was coded: 1 = White/non-Hispanic, 0 = otherwise. ECAS = early childhood attachment security. OXTR rs2254298 was coded: G/G = 0, A/A or A/G = 1. n = 576. Table A3

Predicting Dismissing Attachment States of Mind During the Adult Attachment Interview From

Early Childhood Attachment Security and OXTR rs53576 2 B SE β p R change p Step 1 .04 <.01 Intercept 0.08 0.04 .06 Ethnicity -0.14 0.04 -.14 <.01 Early childhood attachment security (ECAS) -0.15 0.06 -.11 <.01 OXTR rs53576 0.02 0.03 .02 .66 Step 2 .00 .48 Intercept 0.08 0.04 .06 Ethnicity -0.14 0.04 -.14 <.01 Early childhood attachment security (ECAS) -0.10 0.09 -.07 .26 OXTR rs53576 0.02 0.03 .02 .66 ECAS × rs53576 -0.08 0.11 -.05 .48 Note: Ethnicity was coded: 1 = White/non-Hispanic, 0 = otherwise. ECAS = early childhood attachment security. OXTR rs53576 was coded: G/G = 0, A/A or A/G = 1. n = 564.

Table A4 Predicting Dismissing Attachment States of Mind During the Adult Attachment Interview

From Early Childhood Attachment Security and OXTR rs2254298 2 B SE β p R change p Step 1 .06 <.01 Intercept 0.06 0.04 .13 Ethnicity -0.13 0.04 -.14 <.01 Early childhood attachment security (ECAS) -0.16 0.06 -.12 <.01 OXTR rs2254298 0.12 0.04 .13 <.01 Step 2 .00 .83 Intercept 0.06 0.04 .13 Ethnicity -0.13 0.04 -.14 <.01 Early childhood attachment security (ECAS) -0.16 0.06 -.12 .01 OXTR rs2254298 0.12 0.04 .13 <.01 ECAS × rs2254298 -0.03 0.14 -.01 .83 Note: Ethnicity was coded: 1 = White/non-Hispanic, 0 = otherwise. ECAS = early childhood attachment security. OXTR rs2254298 was coded: G/G = 0, A/A or A/G = 1. n = 576.

Table A5 Predicting Preoccupied Attachment States of Mind During the Adult Attachment Interview

From Early Childhood Attachment Security and OXTR rs53576 2 B SE β p R change p Step 1 .03 <.01 Intercept -0.21 0.02 <.01 Ethnicity -0.06 0.02 -.11 .01 Early childhood attachment security (ECAS) -0.08 0.03 -.11 <.01 OXTR rs53576 0.01 0.02 .02 .72 Step 2 .00 .20 Intercept -0.21 0.02 <.01 Ethnicity -0.06 0.02 -.10 .01 Early childhood attachment security (ECAS) -0.03 0.05 -.05 .49 OXTR rs53576 0.01 0.02 .02 .72 ECAS × rs53576 -0.08 0.06 -.09 .20 Note: Ethnicity was coded: 1 = White/non-Hispanic, 0 = otherwise. ECAS = early childhood attachment security. OXTR rs53576 was coded: G/G = 0, A/A or A/G = 1. n = 564.

From Early Childhood Attachment Security and OXTR rs2254298 2 B SE β p R change p Step 1 .03 <.01 Intercept -0.20 0.02 <.01 Ethnicity -0.06 0.02 -.11 <.01 Early childhood attachment security (ECAS) -0.09 0.03 -.12 <.01 OXTR rs2254298 -0.02 0.02 -.03 .45 Step 2 .00 .36 Intercept -0.20 0.02 <.01 Ethnicity -0.06 0.02 -.11 <.01 Early childhood attachment security (ECAS) -0.07 0.03 -.10 .01 OXTR rs2254298 -0.02 0.02 -.03 .46 ECAS × rs2254298 -0.07 0.07 -.04 .36 Note: Ethnicity was coded: 1 = White/non-Hispanic, 0 = otherwise. ECAS = early childhood attachment security. OXTR rs2254298 was coded: G/G = 0, A/A or A/G = 1. n = 576.

Moderation by family financial resources

Within the SECCYD, family income was reported by mothers at each major data collection point from infancy (1 month) through mid-adolescence (15 years) and converted to an income-to-needs ratio by dividing total family income by the US Census-based poverty level income for that family size. This information was used to create the two measures of family financial resources that were used in the present analyses. First, families were classified as below the federal poverty level or not, based on information at the time of the first assessment (1 month). This measure allowed for the most straightforward comparison to the MLSRA study, and 16% of the SECCYD families in this subsample were below the federal poverty line.

Because 4% of the families were missing income data for the 1 month assessment, the sample sizes for the analyses involving poverty status were slightly reduced. Second, family income-to- needs ratios from 1 month through 15 years were averaged to create a dimensional index of family income across childhood and adolescence. Separate models were conducted for poverty status at birth and family income from birth to age 15.

The three-way interactions involving the composite measure of early attachment security,

OXTR SNPs, and family financial resources were not statistically significant as predictors of coherence of mind during the AAI (Tables A7 and A8) or dismissing states of mind (Tables A9 and A10). However, the three-way interaction involving early childhood attachment security,

OXTR rs5376, and poverty status at birth predicted preoccupied attachment states of mind (p = .

005; see Table A11). Follow-up analyses indicated among individuals born into poverty, early childhood attachment security was a marginally significant predictor of lower preoccupied scores for G/G carriers (rpartial = -.33, p = .06, n = 34) but not A allele carriers (rpartial = -.01, p = .97, n = 52). In contrast, among individuals not born into poverty, early childhood attachment security predicted lower preoccupied states of mind for A allele carriers (rpartial = -.19, p = .002, n = 261) but not G/G carriers (rpartial = .07, p = .37, n = 194). The three-way interaction involving early childhood attachment security, OXTR rs53576, and family income-to-needs across childhood and adolescence was not significant. In addition, the three-way interaction between early childhood attachment security, OXTR rs53576, and poverty status at birth did not survive a Bonferroni correction (.05 divided by 12 [the number of three-way interactions tested] = corrected alpha of .

004). The three-way interactions involving OXTR rs2254298 were not statistically significant

(Table A12). Table A7 Predicting Coherence of Mind During the Adult Attachment Interview From Early

Childhood Attachment Security, Family Financial Resources, and OXTR rs53576 B SE β p R2 p Model 1a .05 <.01 Intercept 4.70 0.17 <.01 Ethnicity 0.53 0.16 .14 <.01 Early childhood attachment security (ECAS) 0.25 0.37 .05 .51 OXTR rs53576 -0.08 0.13 -.03 .55 Poverty status -0.20 0.27 -.05 .45 ECAS × rs53576 0.63 0.48 .10 .19 ECAS × poverty status 0.28 0.82 .03 .73 rs53576 × poverty status 0.13 0.34 .03 .71 ECAS × rs53576 × poverty status -0.18 1.06 -.01 .86

Model 2b .09 <.01 Intercept 4.80 0.15 <.01 Ethnicity 0.39 0.15 .11 <.01 Early childhood attachment security (ECAS) 0.09 0.32 .02 .78 OXTR rs53576 -0.11 0.12 -.04 .37 Family income-to-needs 0.11 0.03 .23 <.01 ECAS × rs53576 0.71 0.41 .11 .09 ECAS × family income-to-needs -0.20 0.11 -.12 .08 rs53576 × family income-to-needs -0.04 0.04 -.06 .29 ECAS × rs53576 × family income-to-needs 0.24 0.14 .11 .10 Note: Ethnicity was coded: 1 = White/non-Hispanic, 0 = otherwise. ECAS = early childhood attachment security. OXTR rs53576 was coded: G/G = 0, A/A or A/G = 1. an = 541. bn =

564. Table A8 Predicting Coherence of Mind During the Adult Attachment Interview From Early

Childhood Attachment Security, Family Financial Resources, and OXTR rs2254298 B SE β p R2 p Model 1a .06 <.01 Intercept 4.63 0.16 <.01 Ethnicity 0.55 0.16 .15 <.01 Early childhood attachment security (ECAS) 0.57 0.26 .12 .03 OXTR rs2254298 -0.06 0.16 -.02 .68 Poverty status 0.12 0.20 .03 .56 ECAS × rs2254298 0.31 0.60 .03 .60 ECAS × poverty status 0.16 0.59 .02 .79 rs2254298 × poverty status 0.73 0.38 -.10 .06 ECAS × rs2254298 × poverty status 0.34 1.23 .02 .79

Model 2b .09 <.01 Intercept 4.76 0.14 <.01 Ethnicity 0.42 0.15 .12 <.01 Early childhood attachment security (ECAS) 0.42 0.22 .09 .06 OXTR rs2254298 -0.23 0.14 -.07 .09 Family income-to-needs 0.08 0.02 .17 <.01 ECAS × rs2254298 0.74 0.51 .07 .15 ECAS × family income-to-needs -0.11 0.08 -.07 .16 rs2254298 × family income-to-needs 0.01 0.04 .01 .91 ECAS × rs2254298 × family income-to-needs 0.20 0.17 .06 .23 Note: Ethnicity was coded: 1 = White/non-Hispanic, 0 = otherwise. ECAS = early childhood attachment security. OXTR rs2254298 was coded: G/G = 0, A/A or A/G = 1. an =

551. bn = 576. Table A9 Predicting Dismissing Attachment States of Mind During the Adult Attachment

Interview From Early Childhood Attachment Security, Family Financial Resources, and OXTR rs53576 B SE β p R2 p Model 1a .04 .01 Intercept 0.06 0.05 .24 Ethnicity -0.13 0.05 -.12 <.01 Early childhood attachment security (ECAS) -0.09 0.10 -.06 .41 OXTR rs53576 0.01 0.04 .02 .72 Poverty status 0.04 0.08 .04 .60 ECAS × rs53576 -0.08 0.13 -.04 .57 ECAS × poverty status -0.06 0.23 -.02 .81 rs53576 × poverty status -0.01 0.10 -.01 .92 ECAS × rs53576 × poverty status -0.04 0.30 -.01 .90

Model 2b .07 <.01 Intercept 0.05 0.04 .28 Ethnicity -0.11 0.04 -.11 .01 Early childhood attachment security (ECAS) -0.05 0.09 -.04 .57 OXTR rs53576 0.02 0.03 .03 .50 Family income-to-needs -0.03 0.01 -.22 <.01 ECAS × rs53576 -0.11 0.12 -.07 .32 ECAS × family income-to-needs 0.04 0.03 .08 .24 rs53576 × family income-to-needs 0.01 0.01 .07 .25 ECAS × rs53576 × family income-to-needs -0.05 0.04 -.09 .19 Note: Ethnicity was coded: 1 = White/non-Hispanic, 0 = otherwise. ECAS = early childhood attachment security. OXTR rs53576 was coded: G/G = 0, A/A or A/G = 1. an = 541. bn = 564.

Table A10 Predicting Dismissing Attachment States of Mind During the Adult Attachment

Interview From Early Childhood Attachment Security, Family Financial Resources, and OXTR rs2254298 B SE β p R2 p Model 1a .06 <.01 Intercept 0.06 0.04 .16 Ethnicity -0.13 0.04 -.13 <.01 Early childhood attachment security (ECAS) -0.15 0.07 -.11 .04 OXTR rs2254298 0.07 0.04 .08 .10 Poverty status -0.04 0.06 -.04 .46 ECAS × rs2254298 0.06 0.17 .02 .74 ECAS × poverty status -0.10 0.17 -.03 .54 rs2254298 × poverty status 0.22 0.11 .11 .04 ECAS × rs2254298 × poverty status -0.01 0.34 -.01 .98

Model 2b .08 <.01 Intercept 0.04 0.04 .34 Ethnicity -0.11 0.04 -.11 <.01 Early childhood attachment security (ECAS) -0.13 0.06 -.10 .03 OXTR rs2254298 0.12 0.04 .12 <.01 Family income-to-needs -0.02 0.01 -.15 <.01 ECAS × rs2254298 -0.01 0.14 -.01 .96 ECAS × family income-to-needs 0.02 0.02 .04 .38 rs2254298 × family income-to-needs -0.01 0.01 -.03 .57 ECAS × rs2254298 × family income-to-needs -0.02 0.05 -.02 .71 Note: Ethnicity was coded: 1 = White/non-Hispanic, 0 = otherwise. ECAS = early childhood attachment security. OXTR rs2254298 was coded: G/G = 0, A/A or A/G = 1. an = 551. bn = 576.

Table A11 Predicting Preoccupied Attachment States of Mind During the Adult Attachment

Interview From Early Childhood Attachment Security, Family Financial Resources, and OXTR rs53576 B SE β p R2 p Model 1a .06 <.01 Intercept -0.22 0.03 <.01 Ethnicity -0.06 0.02 -.12 <.01 Early childhood attachment security (ECAS) -0.04 0.05 .06 .42 OXTR rs53576 0.02 0.02 .05 .29 Poverty status 0.07 0.04 .12 .08 ECAS × rs53576 -0.20 0.07 -.21 <.01 ECAS × poverty status -0.28 0.12 -.18 .02 rs53576 × poverty status -0.06 0.05 -.09 .23 ECAS × rs53576 × poverty status 0.44 0.16 .21 <.01

Model 2b .05 <.01 Intercept -0.22 0.02 <.01 Ethnicity -0.05 0.02 -.09 .04 Early childhood attachment security (ECAS) -0.01 0.05 -.01 .91 OXTR rs53576 0.01 0.02 .02 .58 Family income-to-needs -0.01 0.01 -.08 .21 ECAS × rs53576 -0.10 0.06 -.10 .12 ECAS × family income-to-needs 0.04 0.02 .16 .02 rs53576 × family income-to-needs 0.01 0.01 -.03 .64 ECAS × rs53576 × family income-to-needs -0.03 0.02 -.10 .12 Note: Ethnicity was coded: 1 = White/non-Hispanic, 0 = otherwise. ECAS = early childhood attachment security. OXTR rs53576 was coded: G/G = 0, A/A or A/G = 1. an = 541. bn = 564.

From Early Childhood Attachment Security, Family Financial Resources, and OXTR rs2254298 B SE β p R2 p Model 1a .04 <.01 Intercept -0.21 0.02 <.01 Ethnicity -0.06 0.02 -.12 <.01 Early childhood attachment security (ECAS) -0.08 0.04 -.11 .05 OXTR rs2254298 -0.02 0.02 -.05 .33 Poverty status 0.02 0.03 .04 .46 ECAS × rs2254298 -0.02 0.09 -.01 .81 ECAS × poverty status 0.02 0.09 .01 .85 rs2254298 × poverty status 0.04 0.06 .04 .51 ECAS × rs2254298 × poverty status -0.11 0.18 -.03 .56

Model 2b .05 <.01 Intercept -0.21 0.02 <.01 Ethnicity -0.05 0.02 -.10 .02 Early childhood attachment security (ECAS) -0.06 0.03 -.08 .08 OXTR rs2254298 -0.01 0.02 -.02 .65 Family income-to-needs -0.01 0.01 -.14 <.01 ECAS × rs2254298 -0.10 0.08 -.06 .20 ECAS × family income-to-needs 0.03 0.01 .11 .02 rs2254298 × family income-to-needs 0.01 0.01 .07 .14 ECAS × rs2254298 × family income-to-needs -0.05 0.03 -.09 .07 Note: Ethnicity was coded: 1 = White/non-Hispanic, 0 = otherwise. ECAS = early childhood attachment security. OXTR rs2254298 was coded: G/G = 0, A/A or A/G = 1. an = 551. bn =