Stability of Temperament in Toddlers with Autism Spectrum Disorders

Background: Temperament has been defined as individual differences in behavioral styles relating to emotional reactivity, attention, and self-regulation (Rothbart and Bates, 1998). Previous studies have shown that three major domains of temperament, surgency/extraversion, negative affectivity, and attentional control, are stable in typically-developing children from toddlerhood to preschool age (Putnam et al., 2006). However, little is known about the stability of temperament over time in toddlers with ASD. Given the complex and variable patterns of development in ASD, particularly in the toddler and preschool years, understanding whether temperament is a stable construct may provide support for the use of temperament as an additional tool for exploring the heterogeneity of ASD and for understanding variation in individual children.

Objectives: To examine the stability of toddlers’ temperamental traits from age 2 to age 3. 

Methods: Participants included 64 toddlers with ASD who were derived from a clinic- referred sample and assessed by a multidisciplinary team. Measures includes the Toddler Behavior Assessment Questionnaire-Supplemental (TBAQ-S; Goldsmith, 1996). Parents completed the temperament scale prior to their child’s first visit at the mean age of 23 months (range 16.4- 30.8 months) and before their child’s second visit at the mean age of  37 months (range 31.0-48.0 months). The TBAQ consists of 3 composite scales: Surgency, Negative Affectivity, and Attention. Surgency is demonstrated through approach behaviors such as smiling, laughter, and body movements. Negative Affectivity behaviors relate to anger, fear and frustration. Attention is defined by the ability to regulate attention and exercise inhibitory control over behaviors.   

Results: Pearson’s r correlations were computed to assess the association between each composite scale across the first and second visits.  All composite scales demonstrated strong associations over time: Surgency (r =.481, p <.001), Negative Affectivity (r =.559, p <.001), and Attention (r =.561, p <.001). In addition, paired-samples t-tests were conducted to compare changes over time. Results showed a significant positive increase in the Attention composite scale across the two time points (p <.001, d= 0.583) with a moderately large effect size (d = 0.583). This improvement in attention regulation appears to be driven by the subscale Inhibitory Control (p < .001, d = 0.78). 

Conclusions: These findings indicate that, similar to typically developing children, the three major domains of temperament are stable from age 2 to age 3 in toddlers with ASD. Furthermore, like very young children developing typically, their peers with ASD demonstrate significant improvements in attention over this period of time. These results suggest that temperamental factors in young children with ASD behave in a similar manner to those in TD children over the early preschool years, and can be viewed as separate axes for understanding intrinsic characteristics of individual children with ASD.