Description:
<jats:p>Atypical motor behaviors are common among children with autism spectrum disorders (<jats:styled-content style="fixed-case">ASD</jats:styled-content>). However, little is known about onset and functional implications of differences in early motor development among infants later diagnosed with <jats:styled-content style="fixed-case">ASD</jats:styled-content>. Two prospective experiments were conducted to investigate motor skills among 6‐month‐olds at increased risk (high risk) for <jats:styled-content style="fixed-case">ASD</jats:styled-content> (<jats:italic>N</jats:italic><jats:sub>1</jats:sub> = 129; <jats:italic>N</jats:italic><jats:sub>2</jats:sub> = 46). Infants were assessed using the Mullen Scales of Early Learning (<jats:styled-content style="fixed-case">MSEL</jats:styled-content>) and during toy play. Across both experiments, high‐risk infants exhibited less mature object manipulation in a highly structured (<jats:styled-content style="fixed-case">MSEL</jats:styled-content>) context and reduced grasping activity in an unstructured (free‐play) context than infants with no family history of <jats:styled-content style="fixed-case">ASD</jats:styled-content>. Longitudinal assessments suggest that between 6 and 10 months, grasping activity increases in high‐risk infants.</jats:p>