Research Tuesday: Photos Versus PCS – Babies Weigh In
We’re back again with another Research Tuesday post, a series organized by Rachel Wynn of Gray Matter Therapy, in which bloggers are encouraged to write about a research article that they’ve read recently. (You may also know Rachel from her amazing work in advocating for ethical services in skilled nursing facilities.) For our September post, we look at a study done with babies to see how they like different AAC symbols.
SLPs frequently assume that children with AAC needs better understand and prefer photos to other forms of picture symbols used in AAC. In this article, we look at the work of special educator Alexandra DaFonte whose work gives us some insight into this issue.
In this study, she sought to determine if typically developing infants at 6, 9, and 12 months of age responded to two types of graphic symbols used in AAC: actual photographs and Picture Communication Symbols (PCS). An alternating treatment design with counterbalancing was used to see if the infants demonstrated a preference for one type of graphic symbol over another.
Photographs and PCS represented three categories of referents: food, toys, and “other items.” Using a survey, parents identified 12 preferred and 12 non-preferred objects. The researcher used generic items and not things specific to each infant’s personal life experience. Eight foods and eight toys were selected as referents for each infant. Half were preferred and half were non-preferred. Each referent was depicted with both photos and PCS.
The dependent variables measured in this study were the infant’s communicative behaviors, specifically vocalizations, eye gaze, and physical contact (e.g., reaching, grabbing). The active independent variables were the two types of graphic symbols mentioned earlier.
After a warm-up period, the infant was shown a board with a field of four symbols and asked “Where is the ___?” Responses were coded as correct if the baby demonstrated interest in the appropriate symbol by looking at it for at least 3 seconds, making physical contact with it, and/or smiling or vocalizing while looking at it. If the infants did these things for symbols that represented anything else, it was scored as incorrect.
In the intervention condition, three babies received 30 sessions of graphic symbol instruction over two weeks. Graphic symbols for four food items were used in each session. The researcher showed the infant one symbol at a time, labelling it twice. The symbols were put onto a communication board and labelled again (e.g.,”squash, prunes, pear, yogurt”). The researcher then asked which one the baby wanted. The infant was given a spoonful of whichever one was chosen. The three infants who served as controls were exposed to graphic symbols over the same amount of time, but no specific instruction was provided.Both procedural integrity and reliability of data were high (94-97%).
The results demonstrated that infants in any of the age groups did not have a statistically significant preference for one type of symbol over another.
- 6 months: photographs (mean = 58% ) and PCS (mean = 66%)
- 9 months: photographs (mean = 67%) and PCS (mean = 78%)
- 12 months: photographs (mean = 89%) and PCS (mean = 79%)
In terms of communicative modality, only babies in the oldest cohort used vocalizations for communication, which is consistent with existing developmental literature.
It’s still not known the extent to which this applies to older kids or those with developmental disabilities. It reminds us, though, to question our assumptions.
Da Fonte, M. A., & Taber-Doughty, T. (2010). The use of graphic symbols in infancy: How early can we start? Early Child Development and Care, 180 (4), 417-439.
Filed under: PrAACtical Thinking
This post was written by Carole Zangari