Jessie B. Northrup

The development of autism spectrum disorders: variability and causal complexity.

The autism spectrum is highly variable, both behaviorally and neurodevelopmentally. Broadly speaking, four related factors contribute to this variability: (1) genetic processes, (2) environmental events, (3) gene × environment interactions, and (4) developmental factors. Given the complexity of the relevant processes, it appears unlikely that autism spectrum atypicalities can be attributed to any one causal mechanism. Rather, the development of neural atypicality reflects an interaction of genetic and environmental risk factors. As the individual grows, changes in neural atypicality, consequent variation in behavior, and environmental response to that behavior may become linked in a positive feedback loop that amplifies deviations from the typical developmental pattern. WIREs Cogn Sci 2017, 8:e1426. doi: 10.1002/wcs.1426 For further resources related to this article, please visit the WIREs website.

Contingency detection in a complex world A developmental model and implications for atypical development

The present article proposes a new developmental model of how young infants adapt and respond to complex contingencies in their environment, and how this influences development. The model proposes that typically developing infants adjust to an increasingly complex environment in ways that make it easier for them to allocate limited attentional resources and increase opportunities for positive learning experiences. Increased positive experiences with contingency lead to improvements in contingency detection, social behavior, and, ultimately, the development of social and communicative competency. Research relevant to the proposed model will be reviewed and analyzed. In addition, implications for atypical development in the case of autism spectrum disorder will be examined. Specifically, it is predicted that difficulty detecting and responding to increasingly complex contingencies in the environment would lead to particular deficits in interacting with the social world due to the inherent relative complexity of the social world compared to the non-social world. Furthermore, experiences with an unpredictable and confusing social world may lead individuals to increase their experiences with predictability and contingency through restricted and repetitive behaviors and interests. Limitations and areas for future research are presented.

From Using Tools to Using Language in Infant Siblings of Children with Autism

Forty-one high-risk infants (HR) with an older sibling with autism spectrum disorder (ASD) were observed longitudinally at 10, 12, 18 and 24 months of age during a tool use task in a play-like scenario. Changes in grasp types and functional actions produced with a spoon were assessed during elicited tool use. Outcome and vocabulary measures were available at 36 months, distinguishing: 11 HR-ASD, 15 HR-language delay and 15 HR-no delay. Fewer HR-ASD infants produced grasp types facilitating spoon use at 24 months and functional actions at 10 months than HR-no delay. Production of functional actions in HR infants at 10 months predicted word comprehension at 12 months and word production at 24 and 36 months.

Resistance to temptation in toddlers at genetic risk for autism spectrum disorder

Children with autism spectrum disorder often demonstrate difficulties with self-regulation, although studies of this construct in young children with autism spectrum disorder are limited. In this study, developmental changes were examined using a measure of self-regulation appropriate for young children, resistance to temptation. At 22, 28, and 34 months, toddlers with an older sibling with autism spectrum disorder (high risk) and toddlers with typically developing older siblings (low risk) were presented with an appealing toy and instructed not to touch it. Observers coded whether or not children touched the toy and the strategies they used to resist touching it. At 36 months, children were assessed for autism spectrum disorder, yielding three groups: high risk children with autism spectrum disorder, high risk children without autism spectrum disorder, and low risk children. At 22 months, most children, regardless of group, touched the forbidden toy; at 28 and 34 months, many high risk children without autism spectrum disorder and low risk children resisted the temptation to touch the toy, whereas most of the children with autism spectrum disorder did not. Differences in delay strategies were also evident. Some, but not all group differences, were accounted for by differences in language ability. Results highlight one early index of impulse control that differentiates children with emerging autism spectrum disorder from age-mates prior to the third birthday.

Response to changing contingencies in infants at high and low risk for autism spectrum disorder

One recently proposed theory of autism spectrum disorder (ASD) hypothesizes that individuals with the disorder may have difficulty using prior experiences to predict future events [Hellendoorn et al., 2015; Northrup, 2016; Sinha et al., 2014]. To date, this theory has not been tested in infancy. The current study analyzed how young infants at heightened (HR; older sibling with ASD) vs. low risk (LR; no first degree relatives with ASD) for ASD responded to changing contingencies when interacting with two visually identical rattles—one that produced sounds during shaking (Sound), and one that did not (Silent). Infants were given the rattles in a Sound‐Silent‐Sound order at 6 and 10 months, and shaking behavior was coded. Results indicated that LR and HR infants (regardless of ASD diagnosis) did not differ from each other in shaking behavior at 6 months. However, by 10 months, LR infants demonstrated high initial shaking with all three rattles, indicating expectations for rattle affordances, while HR infants did not. Significantly, HR infants, and particularly those with an eventual ASD diagnosis, did not demonstrate an “extinction burst”—or high level of shaking—in the first 10 sec with the “silent” rattle, indicating that they may have difficulty generalizing learning from one interaction to the next. Further, individual differences in the strength of this “extinction burst” predicted cognitive development in toddlerhood among HR infants. Difficulty forming expectations for new interactions based on previous experiences could impact learning and behavior in a number of domains. Autism Res 2017.