ASD is a neurodevelopmental disorder characterised by difficulties in social interaction and communication coupled with repetitive behaviours and restricted interests.
Whereas typically developing (TD) children usually speak their first words by 12 months, many children with ASD only start to speak after their third birthday. Although the majority of individuals with ASD eventually acquire some language skills, 25-30% of children use minimal spoken words throughout childhood. In order to inform the design of interventions that can effectively promote word learning, our research at Lancaster University’s Psychology Department explores how children with ASD learn words in comparison to TD children.
Despite the early age that TD children begin to understand and use language, learning words is deceptively complex. In order to learn a new word, children must first identify what it means. This process is complicated by the fact that there could be lots of unfamiliar things in the child’s environment that they don’t know names for (and a new word could refer to any one of them). TD children overcome this ambiguity by paying attention to social cues (e.g. eye gaze and gestures), developing “assumptions” about how language works (e.g. assuming that one word only refers to one type of thing, so unfamiliar words must refer to unfamiliar objects), and keeping track of associations between words and objects that they experience together.
Once a new word’s meaning has been identified, children must retain its meaning for later use. Importantly, research with TD pre-schoolers has shown that identifying meaning does not guarantee retention – they often forget new words after just 5 minutes! Children’s retention of word meanings is thought to be a gradual process that involves repeatedly pairing words and objects across different times and places.
Once a word’s meaning has been retained, children must learn how to generalise it appropriately. Many words that children first learn are labels for categories that apply to more than one specific object (e.g. “car”, “dog”, “bottle”). The process of learning category names teaches children to pay special attention to the shape of objects, rather than other visual properties such as size, texture, or colour. This is because, for the most part, the shape of an object determines what a thing is and therefore the label it should receive.
Identifying and retaining new words with ASD
In a series of four studies, funded by the UK’s Economic and Social Research Council, we investigated how ASD impacts children’s ability to identify, retain, and generalise the meanings of new words. Our participants included children with ASD (aged 8 years on average) and TD children (aged 5 years on average) matched on language comprehension age (5 years on average for both groups). Matching in this way ensured that children with ASD would be compared against children of a similar developmental level, so they weren’t disadvantaged by their delayed learning.
In Studies 1 and 2, both TD children and children with ASD used their knowledge of familiar words to identify the meanings of unfamiliar words through a process-of-elimination (although the ASD groups were slightly less accurate). After a five-minute delay, children with ASD responded at least as accurately as TD children on measures of retention and generalisation. These experiments also revealed that providing social feedback (i.e. redirecting attention to newly-identified objects using gestures) can enhance retention and generalisation for children with ASD.
In Study 3, TD children and children with ASD identified word meanings by tracking co-occurrences between words and objects with similar accuracy. The groups also achieved similar accuracy on tests of retention and generalisation after five-minute delays. In Study 4, we found that providing social and non-social cues significantly improved both groups’ identification of word meanings, but did not benefit retention or generalisation. Interestingly, children with ASD and TD children who participated in Studies 3 and 4 demonstrated superior retention and generalisation accuracy than the highly-similar participants in Studies 1 and 2. This finding indicates that tracking co-occurrences between words and objects over several instances (as opposed to figuring out a word’s meaning in a single instance) benefits retention of new words for both TD children and children with ASD. However, we also observed that children with ASD took significantly longer to respond correctly across the various stages of our procedure.
The exciting new insights provided by these studies highlight a need to reconsider a long-held assumption that word learning in ASD is functionally different. Our findings imply that fundamental word learning mechanisms, and the relationships between them, are unimpaired by ASD when expectations are based on children’s language development (rather than their chronological age).
Indeed, we have shown that children with ASD are as capable of learning new words as vocabulary-matched TD children when visual and auditory stimuli are presented under favourable conditions. However, children with ASD may require longer to process information, both when identifying and retrieving word meanings. We therefore propose that non-linguistic characteristics of ASD (e.g. sensory problems, attention deficits, and general learning difficulties) may affect word learning by disrupting children’s intake of information in natural learning environments, where stimuli are presented rapidly and distractions are continuous.
From a practical perspective, research such as ours is vital for understanding the optimal language-learning conditions for children with ASD.
Presenting new words under conditions that appeal to the strengths of children with ASD will probably increase the likelihood of learning and ultimately promote long-term vocabulary development. We are continuing to research the impact of ASD on language acquisition and the conditions under which their word learning is most successful.
About the Author
Dr Calum Hartley is a Lecturer in Psychology at Lancaster University. He is an internationally-recognised expert in autism and his research focuses on how this disorder impacts children’s symbolic communication. Calum was awarded his PhD in 2014 which investigated how minimally verbal children with autism understand pictures and words. In 2016, he was awarded a Future Research Leaders Fellowship by the Economic and Social Research Council to profile how children with autism identify, retain, and generalise the meanings of words. Calum is currently supervising several PhD projects exploring this topic. He is also interested in aspects of social cognition, including sharing and ownership, and is involved in a long-running outreach project (‘Science Hunters’) that uses Minecraft to introduce science to children with special educational needs.
Learn more on how Autism has an impact on a student's educational journey in our Succeeding with SEND: focus on Autism video