The executive dysfunction hypothesis of autism has received support from mo
st studies of older people with autism; however, studies of young children
have produced mixed results. Two studies are presented that compare the per
formance of preschoolers with autism (mean = 51 months/4.3 years of age) to
a control group matched on age, and verbal and nonverbal ability The first
study (n = 18 autism and 17 control) found no group differences in perform
ance on 8 executive function tasks (A not B, Object Retrieval, A not B with
Invisible Displacement, 3-Boxes Stationary and Scrambled, 6-Boxes Stationa
ry and Scrambled, and Spatial Reversal), but did find that children with au
tism initiated fewer joint attention and social interaction behaviors. The
second (longitudinal) study of a subset of the children (n = 13 autism and
11 control) from the first study found that neither groups' performance on
Spatial Reversal changed significantly over the course of a year. The resul
ts of these studies pose a serious challenge to the executive dysfunction h
ypothesis of autism.