Table 2.

Participants’ performance over time among the three groups.

	1 High-high (n=85)		2 Low-high (n=137)		3 Low-low (n=42)
Variable	M	SD	M	SD	M	SD	F(comparison)
VD
Age 4.4	9.40	2.96	4.09	2.47	5.93	3.16	97.54**(1>3>2)
Age 5.4	11.76	3.03	6.27	2.96	5.85	3.10	98.77**(1>2=3)
Age 6.4	16.48	3.22	12.55	3.47	11.63	3.28	44.28**(1>2=3)
Age 7.4	20.12	4.06	15.55	4.06	12.54	3.70	58.05**(1>2>3)
Age 8.4	28.45	4.18	23.55	4.99	17.85	5.04	71.81**(1>2>3)
Age 10.4	50.91	6.45	47.30	6.40	33.28	7.19	102.00**(1>2>3)
SD
Age 4.4	9.52	4.51	7.34	4.85	7.98	4.82	5.59**(1>2)
Age 5.4	13.01	2.50	11.60	2.99	10.74	3.70	9.87**(1>2=3)
Age 6.4	14.71	2.29	14.06	2.84	12.33	3.79	9.80**(1>2>3)
TD
Age 7.4	18.35	4.62	17.23	4.74	15.36	5.16	5.56**(1=2>3)
Age 8.4	18.29	4.96	18.36	4.84	16.00	5.01	3.94*(1=2>3)
Age 9.4	20.28	4.34	19.96	4.26	17.95	5.17	4.14*(1=2>3)
MC
Age 4.4	11.87	1.92	9.37	3.25	9.19	3.97	20.39**(1>2=3)
Age 5.4	13.05	2.66	10.77	3.24	10.79	3.38	15.57**(1>2=3)
Age 6.4	11.81	3.18	10.20	2.97	9.76	3.67	8.80**(1>2=3)
MP
Age 7.4	15.02	4.25	13.42	3.51	10.50	4.09	19.38**(1>2>3)
Age 8.4	18.68	3.53	17.01	3.75	13.61	4.43	24.72**(1>2>3)
Age 9.4	22.24	2.74	20.42	3.36	17.54	3.94	28.73**(1>2>3)
Age 10.4	23.95	3.14	22.16	3.45	19.25	4.04	25.52**(1>2>3)
OJ
Age 6.4	42.51	5.72	42.45	4.98	41.57	4.13	<1(1=2=3)
Age 7.4	54.91	5.64	54.04	6.22	51.14	7.03	5.34**(1=2>3)
Age 8.4	59.67	3.46	59.48	3.32	57.12	5.26	7.45**(1=2>3)
RN
Age 5.4	20.46	6.23	23.68	7.89	26.13	7.16	9.66**(1<2=3)
Age 6.4	16.61	5.51	17.01	5.00	18.90	5.44	2.82**(1<3)
Age 7.4	11.45	3.03	12.30	3.47	14.00	3.84	7.95**(1=2<3)
Age 8.4	9.58	2.20	10.21	2.71	11.85	2.98	10.46**(1=2<3)
Age 9.4	8.54	2.13	8.22	2.16	9.94	2.63	9.54**(1=2<3)
Age 10.4	8.04	0.84	8.06	0.97	9.32	1.14	7.39**(1=2<3)
CR1	126.54	9.63	123.26	11.18	116.23	15.18	11.09**(1>2>3)
RF1	1303.40	460.89	1126.00	339.48	883.27	331.71	16.81**(1>2>3)
RC1	32.33	5.21	29.82	6.52	26.62	7.82	11.35**(1>2>3)
IQ2	11.12	2.67	9.77	2.11	10.33	2.62	8.44**(1>2)
ME	4.84	1.03	4.48	1.01	4.43	0.94	3.86**(1>2=3)

Note 1: ME=Mother's Education.

¹Tested at age 11.4.

²Tested at age 4.4.

Note 2: Scores were calculated in seconds in the RN (Rapid Digit Naming task). Thus the quicker, the better.