. Author manuscript; available in PMC: 2018 Mar 8.

Published in final edited form as: Nature. 2017 Jul 12;547(7663):340–344. doi: 10.1038/nature22999

Extended Data Table 2. Concordance in social visual engagement at 21 months, at 36 months, and from 21 until 36 months.

a, Concordance in social visual engagement at 21 months. b, Concordance in social visual engagement in subset seen for repeated testing at 36 months (see Methods). c, Cross-twin concordance in social visual engagement from 21 (time 1, twin 1) until 36 months (time 2, twin 2). In all cases, results are given as intraclass correlation coefficient (ICC) with 95% confidence intervals in parentheses.

a

	Eyes	Mouth	Body	Object	Time Spent Attending to Task
MZ Twins	0.91 (0.85 – 0.95)^**	0.86 (0.76 – 0.92)^**	0.71 (0.52 – 0.83)^**	0.66 (0.46 – 0.80)^**	0.46 (0.19 – 0.67)^*
(N = 41 pairs)	0.91 (0.85 – 0.95)^**	0.86 (0.76 – 0.92)^**	0.71 (0.52 – 0.83)^**	0.66 (0.46 – 0.80)^**	0.46 (0.19 – 0.67)^*
DZ Twins	0.35 (0.07 – 0.59)^*	0.44 (0.16 – 0.65)^*	0.33 (0.04 – 0.57)^*	0.09 (0.00 – 0.38)	0.34 (0.05 – 0.58)^*
(N = 42 pairs)	0.35 (0.07 – 0.59)^*	0.44 (0.16 – 0.65)^*	0.33 (0.04 – 0.57)^*	0.09 (0.00 – 0.38)	0.34 (0.05 – 0.58)^*
Age-, Sex-Matched Non-Siblings	0.16 (0.00 – 0.44)	0.13 (0.00 – 0.42)	0.29 (0.00 – 0.55)	0.14 (0.00 – 0.42)	0.14 (0.00 – 0.43)
(N = 42 pairs)	0.16 (0.00 – 0.44)	0.13 (0.00 – 0.42)	0.29 (0.00 – 0.55)	0.14 (0.00 – 0.42)	0.14 (0.00 – 0.43)
Randomly-Matched Non-Siblings	0.00 (0.00 – 0.29)	0.00 (0.00 – 0.29)	0.00 (0.00 – 0.29)	0.00 (0.00 – 0.30)	0.00 (0.00 – 0.30)
(N = 42 pairs; 10,000 resamplings)	0.00 (0.00 – 0.29)	0.00 (0.00 – 0.29)	0.00 (0.00 – 0.29)	0.00 (0.00 – 0.30)	0.00 (0.00 – 0.30)

b

	Eyes	Mouth	Body	Object	Time Spent Attending to Task
MZ Twins	0.93 (0.75 – 0.98)^**	0.93 (0.77 – 0.98)^**	0.63 (0.08 – 0.88)^*	0.95 (0.81 – 0.99)^**	0.80 (0.19 – 0.94)^**
(N = 11 pairs)	0.93 (0.75 – 0.98)^**	0.93 (0.77 – 0.98)^**	0.63 (0.08 – 0.88)^*	0.95 (0.81 – 0.99)^**	0.80 (0.19 – 0.94)^**
DZ Twins	0.25 (0.00 – 0.60)	0.14 (0.00 – 0.52)	0.21 (0.00 – 0.58)	0.00 (0.00 – 0.41)	0.23 (0.00 – 0.59)
(N = 22 pairs)	0.25 (0.00 – 0.60)	0.14 (0.00 – 0.52)	0.21 (0.00 – 0.58)	0.00 (0.00 – 0.41)	0.23 (0.00 – 0.59)
Randomly-Matched Pairs	0.00 (0.00 – 0.33)	0.00 (0.00 – 0.33)	0.00 (0.00 – 0.33)	0.00 (0.00 – 0.33)	0.00 (0.00 – 0.33)
(N = 33 pairs)	0.00 (0.00 – 0.33)	0.00 (0.00 – 0.33)	0.00 (0.00 – 0.33)	0.00 (0.00 – 0.33)	0.00 (0.00 – 0.33)

c

	Eyes	Mouth	Body	Object	Time Spent Attending to Task
MZ Twins	0.70 (0.40 – 0.86)^**	0.73 (0.45 – 0.88)^**	0.21 (0.00 – 0.58)	0.74 (0.47 – 0.88)^**	0.09 (0.00 – 0.49)
(N = 11 pairs)	0.70 (0.40 – 0.86)^**	0.73 (0.45 – 0.88)^**	0.21 (0.00 – 0.58)	0.74 (0.47 – 0.88)^**	0.09 (0.00 – 0.49)
DZ Twins	0.22 (0.00 – 0.49)	0.07 (0.00 – 0.36)	0.02 (0.00 – 0.31)	0.07 (0.00 – 0.35)	0.00 (0.00 – 0.30)
(N = 22 pairs)	0.22 (0.00 – 0.49)	0.07 (0.00 – 0.36)	0.02 (0.00 – 0.31)	0.07 (0.00 – 0.35)	0.00 (0.00 – 0.30)

Single asterisk (*) signifies P < 0.05 significance value, one-sided comparison relative to 0.

Double asterisk (**) signifies P < 0.01 significance value, one-sided comparison relative to 0.