Table 1.

Participant Characteristics by Diagnostic Group

Characteristic	Groupa
	DS (n = 22)		FX (n = 18)		TD (n = 17)
	Mean	SD	Mean	SD	Mean	SD
CA (in years)	17.59**	3.68	17.58**	3.35	4.54	.58
S-Bb Nonverbal MA (in years)	5.22	1.06	5.03	1.52	4.50	.70
S-Bb Nonverbal IQ	42.32**	6.38	42.56**	8.42	98.00	6.90
OESc age-equivalent (in years)	4.60*	1.78	8.09	4.34	5.62*	.89
TACL–3d age-equivalent (in years)	5.62*	1.47	6.83	1.69	5.95	1.06
Proportion correct false belief	.29	.28	.47	.35	.50	.39
No. correct digit sequencese	3.14	2.42	3.33	2.03	4.35	1.93
Child Behavior Checklist Total T scoref	55.09	8.29	57.06	9.67		—
No. Caucasians	22	—	16	—	14
No. mothers with college degreeg	15	—	13	—	15	—
No. males	12	—	13	—	8	—

^aDS = Down syndrome, FX = fragile X syndrome, TD = typically developing.

^bBased on administration of the Pattern Analysis, Copying, and Bead Memory subtests of the Stanford-Binet Intelligence Scale, 4^th ed.

^cOral Expression Scale of the Oral and Written Language Scales. Age-equivalents are missing for 1 participant with DS and 2 TD participants.

^dTest of Auditory Comprehension of Language–3.

^eBased on the forward recall portion of the Digit Span subtest of the Wechsler Scales of Intelligence for Children, 3rd edition.

^fChild Behavior Checklist/4–18.

^gLevel of maternal education was not available for 1 participant with FX.

^*Significantly different, p < .05, from FX.

^**Significantly different, p <.05, from TD.