Thesis Type

Open Access

Degree Name

Master in Applied Behavior Analysis and Clinical Science


Health Professions

Committee Member(s)

Dr. Michele Williams

Stephanie da Silva

Dr. Rachelle Yankelevitz

Supervising Faculty Member

Dr. Michele Williams


Stimulus-stimulus pairing (SSP) is a respondent conditioning procedure often implemented to elicit vocalizations in children with language delays. Unfortunately, the research showing the effect of increased rates of vocalizations is mixed. Through analogies drawn between SSP and autoshaping, da Silva and Williams (under review) identified variables potentially responsible for increasing the efficacy of SSP (da Silva & Williams, under review). The present study sought to evaluate the relative duration of the inter-trial interval (ITI) and the inter-stimulus interval (ISI). Specifically, the duration of the ITI was systematically varied from 15 s to 60 s and the value of ISI was proportional to the value of ITI. Nine typically developing children, aged 15 to 21 months participated and were randomly assigned to one of three groups. Pairing (trials in which the sound model preceded the delivery of food) and control (trials in which there was no programmed pairing of the delivery of the sound and food) conditions alternated for all subjects. Results were higher rates of vocalizations in the pairing conditions across all subjects. The ratio of approach/withdrawal to the sound differed systematically among the groups with more approach behavior observed with longer ITIs. Moderate and stable rates of vocalizations were observed in 30-s ITI and 60-s ITI conditions. Contrarily, high but decreasing levels of vocalizations were observed in 15-s ITI condition, with more withdrawal behavior from the CS.

Rights Holder

Patricia Eberhardt