Defining Category Abilities and Challenges in Adolescents with Autism VS. Those with Optimal Outcomes

Background:

Many children with autism spectrum disorder (ASD) acquire a sizeable lexicon; however, they may understand and/or store the meanings of words differently from typically developing children (Gastgeb et al., 2006; Kelley et al., 2006; Rapin & Dunn, 2003).  In particular, Kelley et al., (2006) found continuing difficulties with categorical induction, which involves realizing when properties associated with object A should also be associated with object B—such as when A and B have the same labels—in children originally diagnosed with autism who by the age of 7 years had achieved an optimal outcome. 

Objectives:

We assess category induction abilities in more depth, comparing the optimal outcome children when they reached adolescence with mental age-matched typically developing children and high-functioning children with autism.

Methods:

Three groups of young adolescents are being tested:  typically developing (TD, n = 18, M(age) = 13.4 years), high-functioning with autism (HFA, n = 6, M(age) = 12.8 years), and optimal outcome (OO, n = 11, M(age) = 13.0 years).  The children were matched on their WASI scores (M(TD) = 116.39, M(HFA) = 115.83, M(OO) = 116.73), and scored at age level or above on the PPVT (M(TD) = 122.11, M(HFA) = 105.32, M(OO) = 113.73).  All children were given a categorical induction task adapted from Guthiel and Gelman (1997).  Children were shown two sets of pictures.  Set A included five identical animals in different positions (e.g., five yellow snakes) or a single animal (e.g., one yellow snake);  set B included five animals of the same kind but of different appearance (e.g., five snakes of varying colors and patterns, none yellow).  Different properties were assigned to the animals of set A (e.g., blue eyes) vs. set B (e.g., gray eyes).  For the test trial, an entirely new animal of the same kind was presented (e.g., a new snake), and the children were asked whether this animal was likely to have the same property as those in set B or those in set A.  Guthiel and Gelman reported that typically developing adults, and children as young as 9 years of age, consistently extended the property belonging to the more diverse set (e.g., B) to the new animal.

Results:

All groups performed similarly with control questions (comparing single vs. identical sets), showing they understood the task.  The TD children consistently extended the property belonging to the more diverse set (M = 4.67 out of 6, SD = .91), as did the OO children (M = 4.45, SD = .82). In contrast, the HFA children were more likely to extend the property belonging to the homogeneous or single sets (M = 3.67, SD = 1.03).  Both TD and OO children performed significantly better than HFA children (t(22) = 2.26, p< .05 and t(15) = 1.73, p = .05, respectively).

Conclusions:

These OO children seem to have overcome their earlier difficulties with categorical induction as they extended properties much like the TD children.  In contrast, such category difficulties are still evident in high-functioning adolescents who carry the autism diagnosis.