A Picture's Worth a Thousand Words: Examination of Pre-Requisite Skills for the Picture Exchange Communication System

Background: Disordered communication is one of the core deficits of autism. Interventions logically focus on the development of functional communication systems. One of the most frequently used approaches with children who lack speech is the Picture Exchange Communication System (PECS; Bondy & Frost, 2002). In general, PECS users communicate by exchanging pictures for preferred items or activities. Despite PECS growing empirical support, communication outcomes vary considerably and little is known about what accounts for this variation. There has long been debate as to whether there are prerequisite skills, such as picture discrimination or a symbolic understanding of pictures, required for children to use PECS successfully. The present study is an examination of these child characteristics as they relate to communication outcomes using PECS.

Objectives: An overall objective of this study is to determine those children with ASD who benefit most from PECS. Such results will increase our ability to provide early communication interventions that are tailored to match the individual characteristics of children.

Methods: Twenty-two children with a previous diagnosis of an ASD were recruited from a therapeutic summer camp and participated in a 7-week PECS intervention. Data were collected according to a pre-post longitudinal research design. Each child was assessed for entry level/phase of PECS at the beginning of camp, along with a number of child characteristics: age, developmental level (Mullen Scales of Early Learning or Stanford Binet-5), and severity of autism symptoms (Childhood Autism Rating Scale).  Specific cognitive skills assessed pre-treatment included the ability to learn associations between words and pictures and a symbolic understanding of pictures. Outcome variables assessed post-treatment were the phase of PECS attained and speech production.

Results: Most children mastered at least one or two phases of PECS by the end of camp, with a subset mastering three to five phases. Developmental level was highly related to PECS outcomes, while severity of symptoms of autism was not. Associative learning and symbolic ability with pictures were developmental constructs that predicted the phase of PECS attained post-treatment. The majority of children with a symbolic understanding of pictures, that a picture represents real-world items, mastered a more complex, high PECS phase. However, there were a number of children who mastered these phases without a symbolic understanding. These children demonstrated the ability to learn that a particular picture would result in them receiving a specific object through repeated pairings or operant conditioning principles. A subset of children demonstrated functional speech post-treatment.

Conclusions: Even children with significant cognitive delays and severe symptoms of autism can use PECS as a functional communication system. Associative learning is highly predictive of mastering a complex PECS phase and supports the use of behaviourally based teaching strategies with this population. Symbolic ability is facilitative, although not necessary. Implications for outcome expectations and teaching will be discussed.