| 1. |
- Andersson Konke, Linn, 1984-
(author)
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Early Self-Regulation in Infant Siblings : Specific and Shared Associations to Emerging Autism and Co-ocurring ADHD
- 2023
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Doctoral thesis (other academic/artistic)abstract
- The overall aim of this thesis was to examine aspects of self-regulation and the emergence of co-occurring autism and ADHD traits early in life, to enhance our understanding of specific and shared mechanisms underlying these conditions. Previous studies have shown that vulnerabilities in temperament and executive functions (EF) are closely related to both conditions, with overlapping as well as specific features associated to each phenotype. However, most previous studies focus on older children, and it is unclear if specific and shared markers are evident already before symptoms of autism and ADHD emerge. By using an infant-sibling design we were able to follow infants with a family history of autism and/or ADHD, before clinical symptoms emerge. Study I and II focused on infant temperament as either predictors of later autistic and/or ADHD traits or as being predicted by familial quantitative traits, to understand specific and shared associations to autistic and ADHD traits. In Study I, we examined if temperament traits in 1.5-year olds predict autism and ADHD traits at 3 years. Parent-rated temperament showed specific associations to autistic or ADHD traits, respectively. We found some overlap in regulation difficulties across both trait domains. In Study II, we explored the possibility to use probands’ autistic and ADHD traits to predict temperament traits in their 10-month old infant siblings (a between-individual design). We found that higher levels of probands’ autistic symptoms were specifically associated to lower levels of infant sibling’s approach, whereas higher levels of proband’s ADHD symptoms were specifically associated to increased activity levels in the infant siblings. Proband autism and ADHD traits thus provide unique information about the infant siblings’ temperament. Study III focused on specific and shared links between executive functions and deferred gratification and concurrent associations to autistic traits, ADHD traits, and adaptive behaviors in 3-year-olds. We found that deferred gratification may function as a protective factor, moderating autistic traits and adaptive behaviors and thus act as a buffer for adaptive behaviors Together, these studies contribute to our understanding of specific and shared early aspects of self-regulation and their associations to autistic and/or ADHD traits.
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| 2. |
- Bussu, Giorgia, et al.
(author)
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Manipulation of phasic arousal by auditory cues is associated with subsequent changes in visual orienting to faces in infancy
- 2023
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In: Scientific Reports. - : Springer Nature. - 2045-2322. ; 13:1
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Journal article (peer-reviewed)abstract
- This eye-tracking study investigated the effect of sound-induced arousal on social orienting under different auditory cue conditions in 5-month-old (n = 25; n = 13 males) and 10-month-old infants (n = 21; n = 14 males) participating in a spontaneous visual search task. Results showed: (1) larger pupil dilation discriminating between high and low volume (b = 0.02, p = 0.007), but not between social and non-social sounds (b = 0.004, p = 0.64); (2) faster visual orienting (b = − 0.09, p < 0.001) and better social orienting at older age (b = 0.94, p < 0.001); (3) a fast habituation effect on social orienting after high-volume sounds (χ2(2) = 7.39, p = 0.025); (4) a quadratic association between baseline pupil size and target selection (b = − 1.0, SE = 0.5, χ2(1) = 4.04, p = 0.045); (5) a positive linear association between pupil dilation and social orienting (b = 0.09, p = 0.039). Findings support adaptive gain theories of arousal, extending the link between phasic pupil dilation and task performance to spontaneous social orienting in infancy.
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| 3. |
- Bussu, Giorgia, et al.
(author)
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The latent structure of emerging cognitive abilities : An infant twin study
- 2023
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In: Intelligence. - : Elsevier. - 0160-2896 .- 1873-7935. ; 99, s. 101771-101771
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Journal article (peer-reviewed)abstract
- It is well known that genetic factors account for up to 70% of variability in cognition from childhood to adulthood. However, less is known about the first year of life. This study investigated the etiological factors influencing individual variability in different domains of emerging cognitive and motor abilities in early infancy, and to what extent genetic and environmental influences are unique or shared across different domains. We compared multivariate twin models built on scores from the five scales of the Mullen Scales of Early Learning (MSEL) in a community sample of monozygotic and dizygotic twins at 5 months of age (n=567). The results indicated a hierarchical etiological structure whereby a general genetic latent factor accounted for 54% of variance underlying the different domains of emerging cognitive and motor abilities (A=0.54, confidence interval CI=[0; 0.82]). We also found additional genetic influences that were specific to early motor and language development. Unlike previous findings on older children, we did not find significant influences of shared environment on the shared factor (C=0, CI=[0, 0.57]), or any specific scale. Furthermore, influences of unique environment, which include measurement error, were moderate and statistically significant (E=0.46, CI=0.18; 0.81]). This study provides strong evidence for a unitary hierarchical structure across different domains of emerging cognition. Evidence that a single common etiological factor, which we term infant g, contributes to a range of different abilities supports the view that in young infants, intrinsic and general neurodevelopmental processes are key drivers of observable behavioural differences in specific domains.
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| 4. |
- Falck-Ytter, Terje, 1979-
(author)
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From Actions to Faces : Studies of Social Perception in Typical and Atypical Development
- 2010
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Doctoral thesis (other academic/artistic)abstract
- This thesis consists of three eye-tracking studies of social perception in children. Study I and Study II investigated action perception in typically developing infants and preschoolers with Autism Spectrum Disorder (ASD), respectively. Study III investigated face perception in children with ASD. Do infants come to understand others’ actions by a Mirror Neuron System (MNS) that maps others’ actions onto motor plans for similar actions? In Study I, we measured the eye movements while participants observed video clips of an actor's hand placing toys into a bucket. Adults and twelve-month-old infants looked at the bucket before the hand reached it, predicting the goal of the action. This predictive performance was linked to seeing a hand-object interaction. Six-month-olds failed to predict the goal of the action. The development in prediction skills coincides with the age at which infants learn to perform the action themselves. This supports the view that the MNS forms the basis of important social competences such as predicting others' actions. According to the MNS theory of ASD, a failure to map others’ actions onto motor plans for similar actions underlies the social symptoms defining the disorder. In Study II, children with ASD as well as typically developing children and adults were shown the same stimuli as used in Study I. At odds with the theory, all groups used strikingly similar predictive eye movements in action observation. Gaze was reactive in a self-propelled condition, suggesting that prediction is linked to seeing a hand-object interaction. This study does not support the view that ASD is characterized by a global dysfunction in the MNS. Face processing is another core social competence, and research has suggested that many individuals with ASD have face processing impairments. In Study III, we showed faces to young children with ASD and related their looking performance to their behavioural symptoms. Our findings suggest that the socio-communicative information transmitted from faces is processed in a piecemeal fashion in young children with ASD. Much of the variability in face scanning could be explained by individual differences in socio-communicative skills.
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| 5. |
- Falck-Ytter, Terje, Professor, 1979-, et al.
(author)
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Social attention : Developmental foundations and relevance for autism spectrum disorder
- 2023
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In: Biological Psychiatry. - : Elsevier. - 0006-3223 .- 1873-2402. ; 94:1, s. 8-17
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Journal article (peer-reviewed)abstract
- The use of the term Social Attention (SA) in the cognitive neuroscience and developmental psychopathology literature has increased exponentially in recent years, in part motivated by the aim to understand the early development of autism spectrum disorder (ASD). Unfortunately, theoretical discussions around the term have lagged behind its various uses. Here, we evaluate SA through a review of key candidate SA phenotypes emerging early in life, from newborn gaze cueing and preference for face-like configurations to later emerging skills such as joint attention. We argue that most of the considered SA phenotypes are unlikely to represent unique socio-attentional processes but have to be understood in the broader context of bottom-up and emerging top-down (domain-general) attention. Some types of SA behaviors (e.g., initiation of joint attention) are linked to the early development of ASD, but this may reflect differences in social motivation rather than attention per se. Several SA candidates are not linked to ASD early in life, including the ones that may represent uniquely socio-attentional processes (e.g., orienting to faces, predicting others’ manual action goals). Although SA may be a useful super-ordinate category under which one can organize certain research questions, the widespread use of the term without proper definition is problematic. Characterizing gaze patterns and visual attention in infants at elevated likelihood for ASD in social contexts may facilitate early detection, but conceptual clarity regarding the underlying processes at play are needed to sharpen research questions and identify potential targets for early intervention.
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| 6. |
- Falck-Ytter, Terje, Professor, 1979-
(author)
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The breakdown of social looking
- 2024
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In: Neuroscience and Biobehavioral Reviews. - : Elsevier. - 0149-7634 .- 1873-7528. ; 161
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Research review (peer-reviewed)abstract
- Individual differences in social looking are commonly believed to reflect one single heritable dimension tightly linked to autism. Yet, recent data suggest that in human infants, looking to eyes (rather than mouth) and preference for faces (versus non-social objects) reflect distinct genetic influences, and neither appear to have a clear-cut relation to autism.
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| 7. |
- Falck-Ytter, Terje, Professor, 1979-, et al.
(author)
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The sensory-first account of autism
- 2023
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In: Neuroscience and Biobehavioral Reviews. - : Elsevier. - 0149-7634 .- 1873-7528. ; 153
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Research review (peer-reviewed)abstract
- Recent data suggest that infants with later autism have striking differences in sensory processing. We recap these findings and discuss their implications for theories of autism emergence. Due to the primacy of sensory processing for developing cognitive systems, it is time to embrace a ‘sensory-first’ account of autism.
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| 8. |
- Jonsdottir, Lilja Kristin, et al.
(author)
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Autistic children quickly orient away from both eyes and mouths during face observation
- 2023
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In: Journal of autism and developmental disorders. - : Springer Nature. - 0162-3257 .- 1573-3432. ; 53:1, s. 495-502
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Journal article (peer-reviewed)abstract
- Studies have supported two different hypotheses of reduced eye gaze in people with ASD; gaze avoidance and gaze indifference, while less is known about the role of anxiety. We tested these hypotheses using an eye-tracking paradigm that cued the eyes or mouth of emotional faces. Autistic children (n = 12, mean age 7 years) looked faster away from both eyes and mouths than controls (n = 22). This effect was not explained by anxiety symptoms. No difference was found in latency towards either area. These results indicate that attentional avoidance of autistic children is not specific to eyes, and that they do not show attentional indifference to eyes compared to controls. Atypicalities in visual scanning in ASD are possibly unrelated to specific facial areas.
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| 9. |
- Konke, Linn Andersson, et al.
(author)
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Using the Infant Sibling-Design to Explore Associations Between Autism and ADHD Traits in Probands and Temperament in the Younger Siblings
- 2023
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In: Journal of autism and developmental disorders. - : Springer. - 0162-3257 .- 1573-3432.
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Journal article (peer-reviewed)abstract
- The purpose of the current study was to use the infant sibling design to explore whether proband traits of autism and ADHD could provide information about their infant sibling’s temperament. This could help us to gain information about the extent to which infant temperament traits are differentially associated with autism and ADHD traits. We used parent-ratings of autistic traits and ADHD traits (CRS-3) in older siblings diagnosed with autism (age range 4 to 19 years), and their infant siblings’ temperament traits (IBQ) at 9 months of age in 216 sibling pairs from two sites (BASIS, UK, and EASE, Sweden) to examine associations across siblings. We found specific, but modest, associations across siblings after controlling for sex, age, developmental level and site. Proband autistic traits were specifically related to low levels of approach in the infant siblings, with infant developmental level explaining part of the variance in infant approach. Proband ADHD traits were specifically related to high levels of infant activity even after controlling for covariates. Our findings suggest that proband traits of autism and ADHD carry information for infant sibling’s temperament, indicating that inherited liability may influence early emerging behaviours in infant siblings. The impact of sex, age, developmental level and site are discussed.
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| 10. |
- Portugal, Ana Maria, et al.
(author)
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Infants' looking preferences for social versus non-social objects reflect genetic variation
- 2024
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In: Nature Human Behaviour. - : Springer Nature. - 2397-3374. ; 8:1, s. 115-124
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Journal article (peer-reviewed)abstract
- To what extent do individual differences in infants’ early preference for faces versus non-facial objects reflect genetic and environmental factors? Here in a sample of 536 5-month-old same-sex twins, we assessed attention to faces using eye tracking in two ways: initial orienting to faces at the start of the trial (thought to reflect subcortical processing) and sustained face preference throughout the trial (thought to reflect emerging attention control). Twin model fitting suggested an influence of genetic and unique environmental effects, but there was no evidence for an effect of shared environment. The heritability of face orienting and preference were 0.19 (95% confidence interval (CI) 0.04 to 0.33) and 0.46 (95% CI 0.33 to 0.57), respectively. Face preference was associated positively with later parent-reported verbal competence (β = 0.14, 95% CI 0.03 to 0.25, P = 0.014, R2 = 0.018, N = 420). This study suggests that individual differences in young infants’ selection of perceptual input—social versus non-social—are heritable, providing a developmental perspective on gene–environment interplay occurring at the level of eye movements.
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| 11. |
- Portugal, Ana Maria, et al.
(author)
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Pupil size and pupillary light reflex in early infancy : heritability and link to genetic liability to schizophrenia
- 2022
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In: Journal of Child Psychology and Psychiatry. - : John Wiley & Sons. - 0021-9630 .- 1469-7610. ; 63:9, s. 1068-1077
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Journal article (peer-reviewed)abstract
- Background Measures based on pupillometry, such as the pupillary light reflex (PLR) and baseline pupil size, reflect physiological responses linked to specific neural circuits that have been implicated as atypical in some psychiatric and neurodevelopmental conditions.MethodsWe investigated the contribution of genetic and environmental factors to the baseline pupil size and the PLR in 510 infant twins assessed at 5?months of age (281 monozygotic and 229 dizygotic pairs), and its associations with common genetic variants associated with neurodevelopmental (autism spectrum disorder and attention deficit hyperactivity disorder) and mental health (bipolar disorder, major depressive disorder and schizophrenia) conditions using genome-wide polygenic scores (GPSs).ResultsUnivariate twin modelling showed high heritability at 5?months for both pupil size (h2?=?.64) and constriction in response to light (h2?=?.62), and bivariate twin modeling indicated substantial independence between the genetic factors influencing each (rG?=?.38). A statistically significant positive association between infant tonic pupil size and the GPS for schizophrenia was found (??=?.15, p?=?.024), while there was no significant association with the GPS for autism or any other GPSs.ConclusionsThis study shows that some pupil measures are highly heritable in early infancy, although substantially independent in their genetic etiologies, and associated with common genetic variants linked to schizophrenia. It illustrates how genetically informed studies of infants may help us understand early physiological responses associated with psychiatric disorders which emerge much later in life.
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| 12. |
- Rudling, Maja, et al.
(author)
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Infant responses to direct gaze and associations to autism : A live eye-tracking study
- 2023
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In: Autism. - : Sage Publications. - 1362-3613 .- 1461-7005.
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Journal article (peer-reviewed)abstract
- Being looked at is an important communicative signal, and attenuated responses to such direct gaze have been suggested as an early sign of autism. Using live eye tracking, we examined whether direct gaze elicits different gaze responses in infants at ages 10, 14 and 18 months with and without later autism in real-life interaction. The sample consisted of 169 infants: 35 with elevated likelihood of autism and subsequent diagnosis, 94 without subsequent diagnosis and 40 with typical likelihood of autism. Infants in all groups tended to look more towards the adult’s face shortly after the direct gaze occurred. Neither how much nor how quickly the infants responded to the direct gaze differentiated the without elevated likelihood of autism and subsequent diagnosis and with elevated likelihood of autism and subsequent diagnosis groups. Infants in the typical likelihood group looked more at the face after the direct-gaze event than infants in the two elevated likelihood groups, but this result is tentative. In an exploratory analysis, infants in the elevated likelihood of autism and subsequent diagnosis group looked away quicker from faces with direct gaze than infants in the typical likelihood group, but this measure did not correlate with dimensional autism or differentiate between the two elevated likelihood groups. The current results suggest that attenuated behavioural responses to direct gaze in infancy are neither strong nor specific early markers of autism.Lay abstractWhen other people look directly towards us, we often respond by looking back at them, and such direct-gaze responses are important for establishing eye contact. Atypical eye contact is common in autism, but how and when this aspect of autism develops is not well understood. Here, we studied whether how much and how quickly infants respond to others’ direct gaze is associated with autism in toddlerhood. We did this by measuring direct-gaze responses in a playful social interaction using live eye tracking. The study included 169 infants, of whom 129 had an elevated likelihood of developing autism due to having a first-degree family member with the condition, and 40 with typical likelihood of autism. In the elevated likelihood group, 35 were diagnosed with autism spectrum disorder at 3 years of age, and 94 were not. The results showed that infants in all three groups tended to increase their looking towards the adult’s face after the adult looked directly at them. However, neither how much nor how quickly the infants responded to direct gaze by looking back at the adult reliably differentiated the infants with or without subsequent autism. While infants in the elevated likelihood of autism and subsequent diagnosis group tended to look away quicker from faces with direct gaze than infants in the typical likelihood group, this measure did not differentiate between the two elevated likelihood groups. We interpret the results as supporting the view that atypical direct-gaze responses are not early markers of autism.
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| 13. |
- Rudling, Maja, et al.
(author)
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Pre-pragmatic language use in toddlerhood : Developmental antecedents, aetiological factors, and associations to autism
- 2023
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In: JCPP Advances. - : John Wiley & Sons. - 2692-9384. ; 3:1
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Journal article (peer-reviewed)abstract
- BackgroundPragmatic language is key for adaptive communication, but often compromised in neurodevelopmental conditions such as autism spectrum disorder (ASD). Decontextualized language—to talk about events and things beyond here and now—develops early in childhood and can be seen as a pre-pragmatic ability. Little is known about the factors that contribute to decontextualized language use in toddlers and whether these are different from factors contributing to general language development.MethodsWe studied longitudinal associations between parent-rated core language and non-verbal socio-communicative abilities at 14 months of age, and decontextualized language use at 24 months of age in children with typical and elevated likelihood of ASD (total N = 303). Using twin modelling, we also investigated genetic and environmental contributions on decontextualized language and grammar use in two-year-old twin pairs (total N = 374).ResultsCore language ability was a strong predictor of later decontextualized language use in both children with and without an elevated likelihood of ASD. In contrast, social communication was only a significant predictor of decontextualized language use for children with low levels of core language. This pattern was specific to decontextualized language, and not replicated in prediction of concurrent grammatical ability. Further, there was a large genetic influence on decontextualized language at 2 years of age, which mostly overlapped with the genetic influences on grammatical ability. Shared environment influences were significant for grammatical ability, but not found on decontextualized language. In children with an elevated likelihood of ASD, decontextualized language use was negatively associated with autistic symptoms.ConclusionsThis study suggests that decontextualized language is developmentally associated with, yet dissociable from, more general language development measured as grammatical ability. Already at 2 years of age, parental ratings of decontextualized language is associated to clinician-rated symptoms of ASD.
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| 14. |
- Shic, Frederick, et al.
(author)
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Remote, tablet-based assessment of gaze following : a nationwide infant twin study
- 2023
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In: Frontiers in Psychology. - : Frontiers Media S.A.. - 1664-1078. ; 14
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Journal article (peer-reviewed)abstract
- Introduction: Much of our understanding of infant psychological development relies on an in-person, laboratory-based assessment. This limits research generalizability, scalability, and equity in access. One solution is the development of new, remotely deployed assessment tools that do not require real-time experimenter supervision.Methods: The current nationwide (Sweden) infant twin study assessed participants remotely via their caregiver's tablets (N = 104, ages 3 to 17 months). To anchor our findings in previous research, we used a gaze-following task where experimental and age effects are well established.Results: Closely mimicking results from conventional eye tracking, we found that a full head movement elicited more gaze following than isolated eye movements. Furthermore, predictably, we found that older infants followed gaze more frequently than younger infants. Finally, while we found no indication of genetic contributions to gaze-following accuracy, the latency to disengage from the gaze cue and orient toward a target was significantly more similar in monozygotic twins than in dizygotic twins, an indicative of heritability.Discussion: Together, these results highlight the potential of remote assessment of infants' psychological development, which can improve generalizability, inclusion, and scalability in developmental research.
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| 15. |
- Thorup, Emilia, et al.
(author)
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Less frequent face looking in infancy is related to autism likelihood status but not diagnosis : A study of parent-infant interaction
- 2024
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In: Research in Autism Spectrum Disorders. - : Elsevier. - 1750-9467 .- 1878-0237. ; 115
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Journal article (peer-reviewed)abstract
- BackgroundPrevious research suggest that autistic children look less at faces than neurotypically developing children, but this finding is based predominantly on screen-based eye tracking studies, with unfamiliar faces used as stimuli. The aim of the current study was to assess 10-month-olds’ gaze to faces in a more naturalistic context - during free play with a parent - in relation to later autism diagnosis.MethodParents were asked to play with their infant ‘as they usually would’ with a set of toys on the floor. During the first 5 min of play, infant gaze to parent’s face was video coded.ResultsInfants at elevated likelihood of autism (N = 18 with later diagnosis; 46 without later diagnosis), regardless of later diagnostic status, produced fewer gaze shifts towards their parents’ faces than infants at low likelihood of autism (N = 18). Infants in all groups spent only ∼3 % of their time looking at parents’ faces, and there was no group difference in terms of the proportion of time spent looking at faces. There was neither a correlation between infant face looking and scores on the Autism Diagnostic Observation Schedule-2, nor between infant face looking and autistic traits in the parent.ConclusionsDuring toy play, all infants – irrespective of later diagnosis – spent very little time looking at parents’ faces. Infants at elevated likelihood of autism made fewer gazes to their parents’ faces than neurotypically developing infants, which could potentially affect opportunities for social learning. The effect was not specifically linked to later autism diagnosis.
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| 16. |
- Viktorsson, Charlotte, et al.
(author)
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Genetic and environmental contributions to gaze lateralization across social and non-social stimuli in human infants
- 2024
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In: Scientific Reports. - : Springer Nature. - 2045-2322. ; 14:1
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Journal article (peer-reviewed)abstract
- A tendency to look at the left side of faces from the observer’s point of view has been found in older children and adults, but it is not known when this face-specific left gaze bias develops and what factors may influence individual differences in gaze lateralization. Therefore, the aims of this study were to estimate gaze lateralization during face observation and to more broadly estimate lateralization tendencies across a wider set of social and non-social stimuli, in early infancy. In addition, we aimed to estimate the influence of genetic and environmental factors on lateralization of gaze. We studied gaze lateralization in 592 5-month-old twins (282 females, 330 monozygotic twins) by recording their gaze while viewing faces and two other types of stimuli that consisted of either collections of dots (non-social stimuli) or faces interspersed with objects (mixed stimuli). A right gaze bias was found when viewing faces, and this measure was moderately heritable (A = 0.38, 95% CI 0.24; 0.50). A left gaze bias was observed in the non-social condition, while a right gaze bias was found in the mixed condition, suggesting that there is no general left gaze bias at this age. Genetic influence on individual differences in gaze lateralization was only found for the tendency to look at the right versus left side of faces, suggesting genetic specificity of lateralized gaze when viewing faces.
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| 17. |
- Viktorsson, Charlotte, et al.
(author)
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How 18-month-olds with Later Autism Look at Other Children Interacting : The Timing of Gaze Allocation
- 2023
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In: Journal of autism and developmental disorders. - : Springer Nature. - 0162-3257 .- 1573-3432.
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Journal article (peer-reviewed)abstract
- When observing other people during naturally paced and dynamic interactions, it is essential to look at specific locations at the right time to extract a maximum of socially informative content. In this study, we aimed to investigate the looking behavior of typically developing toddlers and toddlers later diagnosed with autism when observing other children interact. The sample consisted of 98 toddlers; 22 in a low-likelihood of autism group, 60 in an elevated likelihood of autism group who did not receive a subsequent diagnosis, and 16 in an elevated likelihood group who did receive an autism diagnosis. Participants performed an eye tracking task at 18 months of age and were assessed for diagnostic outcome at 36 months. The video stimuli consisted of two children interacting, where a boy reaches out for a toy and a girl refuses to give it to him. The low likelihood group showed an expected increase in ratio of looking at the girl’s face after the boy requested the toy, as compared to before (t(21) = -3.337, p = .003). Toddlers with later autism showed a significantly lower ratio of looking at the girl’s face during this time window, as compared to the other groups (F(2,91) = 3.698, p = .029). These findings provide new leads on how social gaze may be different in children with autism in everyday life (e.g., kindergarten), and highlight the need of studying the dynamics of gaze on short time scales.
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| 18. |
- Viktorsson, Charlotte, et al.
(author)
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Preferential looking to eyes versus mouth in early infancy : heritability and link to concurrent and later development
- 2023
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In: Journal of Child Psychology and Psychiatry. - : John Wiley & Sons. - 0021-9630 .- 1469-7610. ; 64:2, s. 311-319
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Journal article (peer-reviewed)abstract
- BackgroundFrom birth, infants orient preferentially to faces, and when looking at the face, they attend primarily to eyes and mouth. These areas convey different types of information, and earlier research suggests that genetic factors influence the preference for one or the other in young children. MethodsIn a sample of 535 5-month-old infant twins, we assessed eye (relative to mouth) preference in early infancy, i.e., before neural systems for social communication and language are fully developed. We investigated the contribution of genetic and environmental factors to the preference for looking at eyes, and the association with concurrent traits and follow-up measures. ResultsEye preference was independent from all other concurrent traits measured, and had a moderate-to-high contribution from genetic influences (A = 0.57; 95% CI: 0.45, 0.66). Preference for eyes at 5 months was associated with higher parent ratings of receptive vocabulary at 14 months. No statistically significant association with later autistic traits was found. Preference for eyes was strikingly stable across different stimulus types (e.g., dynamic vs. still), suggesting that infants' preference at this age does not reflect sensitivity to low-level visual cues. ConclusionsThese results suggest that individual differences in infants' preferential looking to eyes versus mouth to a substantial degree reflect genetic variation. The findings provide new leads on both the perceptual basis and the developmental consequences of these attentional biases.
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| 19. |
- Viktorsson, Charlotte, et al.
(author)
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Stable eye versus mouth preference in a live speech-processing task
- 2023
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In: Scientific Reports. - : Springer. - 2045-2322. ; 13:1
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Journal article (peer-reviewed)abstract
- Looking at the mouth region is thought to be a useful strategy for speech-perception tasks. The tendency to look at the eyes versus the mouth of another person during speech processing has thus far mainly been studied using screen-based paradigms. In this study, we estimated the eye-mouth-index (EMI) of 38 adult participants in a live setting. Participants were seated across the table from an experimenter, who read sentences out loud for the participant to remember in both a familiar (English) and unfamiliar (Finnish) language. No statistically significant difference in the EMI between the familiar and the unfamiliar languages was observed. Total relative looking time at the mouth also did not predict the number of correctly identified sentences. Instead, we found that the EMI was higher during an instruction phase than during the speech-processing task. Moreover, we observed high intra-individual correlations in the EMI across the languages and different phases of the experiment. We conclude that there are stable individual differences in looking at the eyes versus the mouth of another person. Furthermore, this behavior appears to be flexible and dependent on the requirements of the situation (speech processing or not).
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| 20. |
- Viktorsson, Charlotte, et al.
(author)
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Sustained looking at faces at 5 months of age is associated with socio-communicative skills in the second year of life
- 2024
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In: Infancy. - : John Wiley & Sons. - 1525-0008 .- 1532-7078.
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Journal article (peer-reviewed)abstract
- Efficiently processing information from faces in infancy is foundational for nonverbal communication. We studied individual differences in 5-month-old infants' (N = 517) sustained attention to faces and preference for emotional faces. We assessed the contribution of genetic and environmental influences to individual differences in these gaze behaviors, and the association between these traits and other concurrent and later phenotypes. We found an association between the mean duration of looking at a face (before looking away from it) at 5 months and socio-communicative abilities at 14 months (β = 0.17, 95% CI: 0.08; 0.26, p < 0.001). Sustained attention to faces predicted socio-communicative abilities over and above variance captured by mean fixation duration. We also found a statistically significant but weak tendency to prefer looking at smiling faces (relative to neutral faces), but no indication that variability in this behavior was explained by genetic effects. Moderate heritability was found for sustained attention to faces (A = 0.23, CI: 0.06; 0.38), while shared environmental influences were non-significant for both phenotypes. These findings suggest that sustained looking at individual faces before looking away is a developmentally significant ‘social attention’ phenotype in infancy, characterized by moderate heritability and a specific relation to later socio-communicative abilities.
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| 21. |
- Zuffa, Simone, et al.
(author)
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Early-life differences in the gut microbiota composition and functionality of infants at elevated likelihood of developing autism spectrum disorder
- 2023
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In: Translational Psychiatry. - : Springer Nature. - 2158-3188. ; 13
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Journal article (peer-reviewed)abstract
- Evidence from cross-sectional human studies, and preliminary microbial-based intervention studies, have implicated the microbiota-gut-brain axis in the neurobiology of autism spectrum disorder (ASD). Using a prospective longitudinal study design, we investigated the developmental profile of the fecal microbiota and metabolome in infants with (n = 16) and without (n = 19) a family history of ASD across the first 36 months of life. In addition, the general developmental levels of infants were evaluated using the Mullen Scales of Early Learning (MSEL) test at 5 and 36 months of age, and with ADOS-2 at 36 months of age. At 5 months of age, infants at elevated-likelihood of ASD (EL) harbored less Bifidobacterium and more Clostridium and Klebsiella species compared to the low-likelihood infants (LL). Untargeted metabolic profiling highlighted that LL infants excreted a greater amount of fecal & gamma;-aminobutyric acid (GABA) at 5 months, which progressively declined with age. Similar age-dependent patterns were not observed in the EL group, with GABA being consistently low across all timepoints. Integrated microbiome-metabolome analysis showed a positive correlation between GABA and Bifidobacterium species and negative associations with Clostridium species. In vitro experiments supported these observations demonstrating that bifidobacteria can produce GABA while clostridia can consume it. At the behavioral level, there were no significant differences between the EL and LL groups at 5 months. However, at 36 months of age, the EL group had significantly lower MSEL and ADOS-2 scores compared to the LL group. Taken together, the present results reveal early life alterations in gut microbiota composition and functionality in infants at elevated-likelihood of ASD. These changes occur before any behavioral impairments can be detected, supporting a possible role for the gut microbiota in emerging behavioral variability later in life.
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