Date of Award


Degree Type


Degree Name

Doctor of Philosophy (PhD)



First Advisor

Diana L. Robins - Chair

Second Advisor

Roger Bakeman

Third Advisor

Chris Henrich

Fourth Advisor

Lauren B. Adamson


Autism spectrum disorders (ASDs) are a group of disorders that affect social, communication, and behavioral development. Identification of clinically distinct subtypes of ASDs, especially in the developmental period when delays or deficits are first recognized (i.e., in the first few years of life), can lend clues to etiology and trajectory and enhance current knowledge on early manifestations of the disorders. Moreover, identification of clinically distinct subtypes of ASDs may inform early identification efforts. Past research suggests that social relations, verbal abilities, nonverbal abilities, and the presence of certain stereotyped interests and behaviors (SIB) may be important factors in delineating subtypes of ASDs in toddlers. Yet there is no published study that examines empirically derived subtypes in a sample of such young children. Therefore, the purpose of this study was to determine whether clinically distinct subtypes can be derived from a sample of toddlers who fail an autism screen and are subsequently diagnosed with developmental concerns, including an ASD. Results found that subtypes delineated by social-communicative maturity were found in both of the aforementioned samples of children. Furthermore, the ASD only sample was also distinguished by rate and intensity of certain types of SIB. Implications for autism theory, early identification, and early intervention are discussed.


Included in

Psychology Commons