• Autism;
  • developmental sequence;
  • developmental structure;
  • mental retardation

Abstract Aspects of developmental sequences and structures were assessed in low- and high-Functioning autistic and non-autistic developmentally disabled children. Specific developmental issues examined included sequences, regressions and profiles. Classification into the high- or low-functioning groups was based on a full stale IQ cutoff of 50. In general, there were few differences in the sequences of development among the groups. However, the autistic children were more likely than non-autistic children to display developmental regressions and unevenness across developmental domains. These developmental peculiarities were more pronounced in the low- as compared to high-functioning autistic children. These findings are discussed with regard to issues of developmental processes, classification and autism.