Investigating the role of attentional biases on language development in autistic children and neurotypical children
Creators: name: Rothwell, Charlotte
Publisher: name: Lancaster University
Year: 2023

description: From their first year of life, neurotypical children learn words rapidly
 and with
 
 apparent ease. However, many autistic children experience delays in
 language development and struggle to acquire vocabulary. To learn a word,
 children must identify the intended referent (referent selection) and then
 store the word-referent association in memory for later retrieval
 (retention). In light of recent evidence that referent selection and
 retention mechanisms are unimpaired in autism, difficulties acquiring
 vocabulary may be attributed to differences in attention to stimuli.
 Autistic children often focus intensely on preferred
 
 stimulus categories, potentially disregarding stimuli that do not align
 with their preferential interests. Therefore, the purpose of this thesis
 was to examine how attentional salience of stimuli influences autistic and
 neurotypical children’s novel word learning.
 
 
 The three studies that comprise this thesis investigated how children’s
 stimulus
 
 preferences and interests influence their referent selection and retention
 after delays of 5 minutes and 24 hours. Participants were neurotypical and
 autistic children with delayed language development matched on receptive
 vocabulary (age equivalent ~5 years). All studies utilised touch-screen
 technology to capture children’s response times and accuracy. Studies 1
 and 2 examined how children’s word learning is impacted by the presence of
 target and distractor stimuli related to a preferred stimulus category.
 ‘High interest’ stimuli in these
 
 studies were novel animals, as they are often favoured by both
 neurotypical and autistic children. Participants’ interest in animals was
 confirmed via a questionnaire. Study 3 investigated how children’s
 individual preferences for novel objects (i.e. generic experimental
 stimuli) affect novel word learning. Studies 2 and 3 employed a novel
 combination of accuracy and looking measures, exploring children’s
 in-trial visual attention and how this
 
 predicted children’s response accuracy.
 
 
 In Study 1, autistic and neurotypical children were taught novel words
 associated with unfamiliar animals (high interest stimuli) and objects
 (neutral interest stimuli) in the presence of high interest animal
 distractors during referent selection. This manipulation enabled us to
 investigate how salient non-target stimuli affect novel word learning. The
 presence of interesting distractor stimuli enhanced autistic children’s
 encoding of novel word-referent associations by increasing attention
 across the whole visual scene. Study 2 studied how
 
 children’s categorical interests influenced their word learning. Children
 learnt names for novel animals and novel objects, but the distractor
 stimuli presented at referent selection were neutral interest familiar
 objects, allowing us to identify how perceptual distinctions between
 stimulus categories influences novel word-referent encoding. Categorically
 interesting novel stimuli, that stood out from less interesting
 distractors, enhanced autistic children’s retention of novel words after 5
 minutes. However, autistic children demonstrated a substantial
 
 increase in their retention of novel object labels between 5 minutes and
 24 hours, outperforming neurotypical peers in both conditions following
 sleep consolidation. Study 3 examined how children’s individual
 preferences for novel objects impacts word learning (labels were taught
 for liked and disliked objects, identified by children in a preceding
 task). The findings showed that idiosyncratic preferences for novel
 experimental stimuli, an object category that is unlikely to align with
 children’s pre-existing interests, do not affect autistic or
 
 neurotypical children’s attention allocation to an extent that is
 sufficient to impact retention after 5 minutes or 24 hours. Our looking
 data in Studies 2 and 3 indicated that greater visual attention towards
 stimuli predicted novel word retention. Moreover, observed population
 differences in visual attention did not directly translate to diminished
 behavioural accuracy. 
 
 
 This thesis advances understanding of relationships between word learning
 processes and attentional mechanisms in autism and neurotypical
 development. Our data demonstrate that categorically interesting stimuli
 aid novel word learning in autistic children. This finding, coupled with
 observed relationships between visual input at referent selection and
 novel word retention, confirm that increased attentional allocation to
 stimuli during encoding leads to more robust novel word-referent
 representations. Contrasts between population differences in visual
 attention and response accuracy outcomes suggest that autistic children
 potentially achieve similar results through a different route than
 neurotypical peers. Our novel combination of visual attention and accuracy
 measures highlight the importance of choosing dependent variables that
 appropriately target mechanisms of interest and the risk of drawing
 
 inaccurate conclusions based on looking behaviour alone. Given that
 stimulus categories influenced autistic and neurotypical children’s
 learning to different extents, researchers should carefully select
 experimental stimuli that appeal to different populations comparably.
 Overall, our findings have the potential to inform practice in clinical
 and educational settings, providing insight into how learning contexts can
 be optimised for maximally efficient language acquisition.