. Author manuscript; available in PMC: 2023 Mar 1.

Published in final edited form as: Dev Sci. 2022 May 30;26(2):e13281. doi: 10.1111/desc.13281

Table 2.

HLM models of change: Longitudinal growth for all measures of dyadic interaction.

Measure	Parameter	Coeff.	SE
Prop. of intervals in each posture
Supine	Intercept, β₀₀	0.65^***	0.10
	Linear Growth, β₁₀	−0.19^***	0.03
	Quadratic Growth, β₂₀	0.01^***	0.002
Supported sitting	Intercept, β₀₀	0.30^***	0.07
Supported sitting	Linear Growth, β₁₀	−0.04^**	0.01
Independent sitting	Intercept, β₀₀	−0.03	0.05
	Linear Growth, β₁₀	0.21^***	0.03
	Quadratic Growth, β₂₀	−0.01^***	0.004
Posture transitions	Intercept, β₀₀	0.02	0.01
Posture transitions	Linear Growth, β₁₀	0.01^***	0.003
Prop. of intervals in each orientation type
Facing	Intercept, β₀₀	0.78^***	0.08
Facing	Linear Growth, β₁₀	−0.06^***	0.01
Right angles	Intercept, β₀₀	0.21^**	0.07
Right angles	Linear Growth, β₁₀	0.04^**	0.01
Back-to-front	Intercept, β₀₀	0.06^**	0.02
Different directions	Intercept, β₀₀	0.02^**	0.01
Orientation transitions
Prop. of intervals	Intercept, β₀₀	0.001	0.01
Prop. of intervals	Linear Growth, β₁₀	0.01^***	0.002
Object density
Mean number of objects	Intercept, β₀₀	1.85^**	0.58
Mean number of objects	Linear Growth, β₁₀	1.81^***	0.40
Object placement
Prop. of intervals	Intercept, β₀₀	0.17^***	0.01
Prop. infant-initiated	Intercept, β₀₀	0.05	0.03
	Linear Growth, β₁₀	0.03^***	0.01

p < .05

^**

p < .01

^***

p < .001