Table 1.

Characteristics of the sample (N = 28).

Age in years; mean (SD)	11.29 (0.40)
Proportion male	89.3%
Proportion identified as ‘White British’	77.8%
Proportion with parents ‘married or cohabiting’	70.4%
WISC-IV verbal comprehension index; mean (SD)	90.46 (18.35)
WISC-IV perceptual reasoning index; mean (SD)	98.54 (16.39)
WISC-IV working memory index; mean (SD)	87.04 (15.46)
WISC-IV processing speed index; mean (SD)	82.32 (17.44)
WISC-IV full-scale IQ; mean (SD)	87.86 (17.44)

SD: standard deviation; WISC-IV: Wechsler Intelligence Scale for children, fourth UK edition.