Participants
Participants were recruited from a larger, ongoing study of cognitive
control development in early childhood at
[details omitted for
double-anonymized peer review]. Participants were originally recruited
using research registries, community events and advocacy groups,
clinics, early intervention programs, and word of mouth. Exclusionary
criteria included medical disorders or medications impacting the central
nervous system, a history of seizures or seizure medication, inability
to complete parent questionnaires or testing in English, prolonged
prenatal substance exposure, and significant sensory or motor
impairments or major physical abnormalities which limited ability to
complete the testing battery.
Participants included 19 verbal autistic children (16 male) aged 3.9 to
6.8 years (Mage = 5.6, SD = 0.82 years) at their initial
visit. Sixteen children returned for the follow-up visit aged 4.0 to 6.9
years (Mage = 5.6 SD = 0.89). All participants used
flexible phrase speech and had an age equivalent of at least 18 months
as assessed via the Visual Reception domain of the Mullen Scales of
Early Learning (MSEL; Mullen, 1995) as part of their participation in
the larger study within the previous two years. Diagnosis of an autism
spectrum disorder was determined using the ADOS-2 (Lord, Luyster, et
al., 2012, Lord, Rutter et al., 2012) and the ADI-R (Rutter et al.,
2003; Kim & Lord, 2012) and DSM-5 criteria (American Psychiatric
Association, 2013) based on expert judgment of a licensed clinical
psychologist11During the COVID-19 pandemic, the CARS-2 was added
to the protocol to further confirm that children met standardized
criteria for an autism spectrum disorder.. Sample characteristics are
reported in Table 1.