Table 1.

Number of days to reach criterion on t he Two-item and Two-item Reversal tasks, number of boxes opened on day 5 for Hamilton Search and Hamilton Search Set-Breaking tasks, and proportion of correct choices for the Hamilton Search Forced Set-Breaking task, by sex and birth weight category.

Performance	Two-item	Two-item Reversal	Hamilton Search	HS-Set Breaking	HS-Forced Set Breaking
Low BW, Female
N	13	13	6	6	6
Mean	3.69	8.08	3.48	2.03	13.00
Stdev	1.60	3.71	0.48	0.47	8.51
Normal BW, Female
N	74	60	31	13	11
Mean	4.13	7.05	2.91	2.36	11.18
Stdev	2.38	3.25	0.61	0.55	6.306
High BW, Female
N	20	17	10	6	7
Mean	3.55	5.88	2.94	1.97	5.14
Stdev	2.09	2.29	0.30	0.26	5.43
Low BW, Male
N	13	13	5	6	6
Mean	3.15	5.77	2.89	2.28	7.67
Stdev	1.62	2.71	0.48	0.50	8.07
Normal BW, Male
N	84	72	45	21	22
Mean	3.75	6.22	2.96	2.33	9.59
Stdev	1.85	2.89	0.52	0.50	9.05
High BW, Male
N	16	10	7	4	4
Mean	3.75	6.50	2.83	2.10	12.00
Stdev	2.11	3.03	0.26	0.58	9.76
Overall
N	220	185	104	56	56
Mean	3.82	6.57	2.96	2.25	9.68
Stdev	2.06	3.04	0.52	0.50	8.03