Table 1.

Uncorrected Means and Standard Deviations (SDs) for PI, N170 and P400 recorded from children in the two groups (No-sibling, Sibling).²

P1
	Condition	No-sibling group		Sibling group
		Means	SDs	Means	SDs
P1 amplitude	Adult upright	15.62	5.3	12.30	6.4
	Adult inverted	16.53	5.6	13.31	8.4
	Newborn upright	13.56	4.6	12.59	7.9
	Newborn inverted	14.83	6.8	11.26	6.6
P1 latency	Adult upright	128.83	19.8	129.10	17.5
	Adult inverted	124.77	16.0	122.10	17.2
	Newborn upright	123.75	21.8	125.02	11.3
	Newborn inverted	123.78	20.8	121.56	8.4

N170
	Condition	No-sibling group		Sibling group
		Means	SDs	Means	SDs
N170 amplitude	Adult upright	1.00	7.1	−2.27	5.5
	Adult inverted	2.03	6.4	−1.60	5.2
	Newborn upright	2.10	6.2	−1.40	5.9
	Newborn inverted	0.82	8.0	−2.42	4.6
N170 latency	Adult upright	211.10	33.5	218.83	30.4
	Adult inverted	210.89	32.9	216.61	32.5
	Newborn upright	212.80	39.6	220.76	37.4
	Newborn inverted	209.35	29.0	213.77	32.9

P400
	Condition	No-sibling group		Sibling group
		Means	SDs	Means	SDs
P400 amplitude	Adult upright	15.95	5.3	14.41	6.2
	Adult inverted	16.84	5.1	15.28	7.6
	Newborn upright	15.85	5.6	11.83	5.9
	Newborn inverted	18.41	8.0	13.87	6.7