Reading to infants and young children is associated with stronger vocabulary skills at age three

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Shared reading between parents and very young children, including infants, is associated with stronger vocabulary skills for nearly all children by age 3, say physicians at Rutgers Robert Wood Johnson Medical School.

According to research published in The Journal of Pediatrics, this is true also for children who genetically may be vulnerable to barriers in learning, attention and behavior development.

“In a supportive environment, children who may be genetically at-risk, do just as well as their peers,” said Manuel Jimenez, a developmental pediatrician and assistant professor of pediatrics and family medicine and community health at the medical school, who is lead author of the study.

The children in the study were tested as part of the Fragile Families and Child Wellbeing Study which examined the development of children born to unmarried families who were at greater risk of living in poverty

Jimenez explained that the study looked at how children respond differently to shared reading based on genetic characteristics.

Using data from the Fragile Families and Child Wellbeing Study, which has followed the development of nearly 5,000 children in large U.S. cities born between 1998 and 2000, the team assessed the difference in vocabulary skill development based on genetic differences in two neurotransmitter systems that have implications in learning development, memory and impulse control.

The study found that shared reading with children at 1 year old was associated with higher vocabulary scores on a standardized assessment at age 3, in line with previous published studies.

Children with genetic variations that put them at-risk fared just as well as their peers on the assessment when shared reading was conducted at age 1.

However, at-risk children who were not exposed to shared reading did poorly on the same vocabulary assessment.

“We found that reading with very young children can be quite powerful and really makes a difference in a child’s development, particularly with children who may be vulnerable to developmental delays,” said Jimenez.

According to Jimenez, scientists are just starting to understand how genes influence complex behaviors and how science can be applied to improving lives through patient care.

The research underscores the importance of a positive environment with close parental contact and its direct correlation to favorable child development, even when a child may be at-risk for learning and behavioral challenges.

Children who are read to by their parents have stronger vocabulary skills by age 3.

Daniel Notterman, a pediatrician, professor of molecular biology and co-investigator of the Fragile Families study at Princeton University, clinical professor of pediatrics at Robert Wood Johnson Medical School, and co-author of the study, concurs.

“Biological measures give us another way to identify children for which interventions, in this case reading, may have the greatest benefit,” he said. “Although there is already evidence of the positive effects of shared reading, this study provides additional verification and a more quantitative picture of the link between a child’s environment, biological makeup, and development.”

Both researchers emphasized that parents need to spend time reading with their children every day, as findings from the study provide support for literacy promotion at an early age.

“The bottom line is that children respond positively to shared reading at an early age and doing so is one way to improve language skills for all children,” said Jimenez.


Typically developing infants are sensitive to others’ gaze from birth (Batki et al., 2000Farroni et al., 2002). Over the first year they follow gaze first reflexively (Hood et al., 1998Farroni et al., 20002004) and then learn its referential function (Woodward, 2003Csibra and Volein, 2008Senju et al., 2008).

Being able to follow someone’s gaze, and jointly attend to objects, is thought to provide a key mechanism by which infants acquire a vocabulary (Baldwin, 19911993Schafer and Plunkett, 1998Houston-Price et al., 2006) and many studies have associated joint attention ability with later vocabulary growth (Carpenter et al., 1998Morales et al., 1998Charman, 2003Brooks and Meltzoff, 2008).

Children with autism spectrum disorder (ASD) often have poor joint attention, evidenced by reduced gaze following in naturalistic situations (e.g., Dawson et al., 2004), and this has been highlighted as one of the most reliable and consistent indicators of ASD during childhood (e.g., Baron-Cohen et al., 1996Charman, 2003).

Given that the rate of learning difficulty is often high in children with ASD (∼55%; Charman et al., 2011) and there is frequent language delay (e.g., Charman et al., 2003), studies have suggested that poor language in ASD may be explained, in part, by difficulties with engaging in joint attention (e.g., Mundy et al., 1994Pickard and Ingersoll, 2015).

For example, in their study of children between 22 to 93 months of age, Pickard and Ingersoll used the Early Social Communication Scales, a play-based structured assessment that captures both the child’s initiating and responding to joint attention, to show that failing to follow someone’s gaze or pointing to an object were best predictors of concurrent language.

In addition, an intervention targeting joint attention in children with ASD yielded better expressive language outcomes when compared to an intervention increasing symbolic play (Gulsrud et al., 2014).

There are several reasons why children with ASD may struggle to use joint attention for learning language. Firstly, they may not correctly or consistently follow someone’s gaze to the object they are labeling. This could be because they do not spend enough time looking at faces to notice or process the gaze shifts.

Alternatively, despite looking at faces and eyes, they still may not shift their gaze in the same direction as the person communicating with them. It could also be that, despite correctly following gaze, they do not spend enough time on the gazed at object to learn about it. Looking less toward the gazed at object may also reflect poor understanding of the referential nature of gaze.

That is, word learning could fail not because there was insufficient time dedicated to encoding object properties, but because unlike typically-developing children (Gliga and Csibra, 2009), children with ASD may have a reduced appreciation of the referential link between the uttered word and the gazed at object.

Recently, eye-tracking studies have allowed a detailed quantification of attention distribution during joint attention episodes, thus making it possible to reveal the different sources of atypicality mentioned above. Eye-tracking studies investigating how young children with ASD respond to gaze cues, are summarized in Tables 1.11.3.

We review studies of children up to 4 years of age, because beyond this age, children with a diagnosis of ASD are likely to take part in intervention programs which may affect performance in experimental studies.

Since it is important to investigate the ability to respond to referential cues when it most contributes to vocabulary growth (Morales et al., 2000) we give special attention to longitudinal studies of infants at familial risk for ASD, which study infants during their first 2 years of life. This population has a higher likelihood of developing ASD themselves (∼20%, Ozonoff et al., 2015; general population ∼1–2%). A further 20% will exhibit subthreshold symptoms of ASD or developmental delay (Messinger et al., 2013).

TABLE 1.1

Results for attention to the face from eye-tracking studies exploring joint attention in young children with ASD or at-risk for ASD.

Paying attention to faces
ArticleParticipantsMeasureASD vs. others1Additional information2
Chawarska et al., 2013High-risk∗∗, LR 6 mo.F/SceneLessConditions include dyadic bids and gaze shifts
E/SceneSame
Jones and Klin, 2013High-risk∗∗, LRDuring dyadic bids
2 mo. to 6 mo.E/SceneMore
6 mo. to 24 mo.E/SceneLess
Nyström et al., 2017High-risk, LRLIVE interaction (not screen-based)
10 mo.F/SceneLess200–700 ms after mutual gaze
F/SceneSameAcross the whole session
Thorup et al., 20162018High-risk, LRLIVE interaction (not screen-based)
10 mo.F/SceneSameNo difference in the time to engage the actor
This studyHigh-risk∗∗, LR 15 mo.F/SceneSameDuring gaze shifts
Chawarska et al., 2012ASD, TD 13–25 mo.F/SceneLessDuring dyadic bids
F/SceneSameDuring gaze shifts
Billeci et al., 2016ASD, TD 18–30 mo.F/SceneSameDuring gaze shifts
F/SceneMoreWhen toddler initiates joint attention
Jones et al., 2008ASD, TD 24–27 mo.E/SceneLessDuring dyadic bids
Vivanti et al., 2017ASD, TD 48 mo.F (not scaled)LessDuring gaze shifts

Studies were chosen where attention had to be distributed between faces and other objects in the scene/background. Studies are organized by participant age (youngest to oldest) to highlight any developmental progression. E, eye area; F, whole face area. High familial risk studies without diagnostic outcome comparing LR with HR; ∗∗High risk studies with analysis by outcome. TD, typically developing; ASD, diagnosed. 1‘Less’ indicates ASD or high familial risk participants had lower values than typically developing/low familial risk participants, ‘more’ indicates ASD or high familial risk participants had greater values. 2This column contains additional relevant information regarding experimental conditions.

TABLE 1.3

Results for attention engagement with objects from eye-tracking studies exploring joint attention using gaze following in young children with ASD or at-risk for ASD.

Engaging attention with gazed at objects
ArticleParticipantsMeasureASD vs. others1Additional information2
Engaging attention with gazed at objects
Bedford et al., 2012High-risk∗∗, LRR/(R + D + O + F)
7 mo.Same
13 mo.Less
This studyHigh-risk∗∗, LR 15 mo.(R-D)/(R + D)SameAll groups above chance
R/(R + D + O + F)Less
Billeci et al., 2016ASD, TD 18–30 mo.R/(R + D + O + F)Same
Gliga et al., 2012High-risk∗∗, LR 36 mo.R/(R + D)SameAll groups above chance
Falck-Ytter et al., 2015ASD 41 mo. TD 21 mo.R-D First fixationLess
Vivanti et al., 2017ASD, TD 48 mo.R (not scaled)Less
R (not scaled)Trending lessAfter excluding trials with dwell time on face < 100 ms during gaze shift
Thorup et al., 2017ASD, TD 38–115 mo.R/(R + D) First fixationLessWhen referent was not an object of high interest, i.e., a pot plant
R/(R + D) First fixationSameWhen referent was an object of high interest, i.e., trains/vehicles

Studies are organized by participant age (youngest to oldest) to highlight any developmental progression. R, object referenced; D, distractor object; F, whole face area; O, other areas of screen. High familial risk studies without diagnostic outcome comparing LR with HR; ∗∗High familial risk studies with analysis by outcome. TD, typically developing; ASD, diagnosed. 1‘Less’ indicates ASD or high familial risk participants had lower values than typically developing/low familial risk participants. 2This column contains additional relevant information regarding experimental conditions or comparisons to chance (where appropriate).

We asked first whether studies found decreased engagement with faces, when children with ASD were presented with scenes in which attention had to be distributed between people and objects. These studies have yielded a mixed picture, with some finding less looking to faces in ASD (Chawarska et al., 20122013Jones and Klin, 2013), others more looking (Billeci et al., 2016) and yet others no difference between groups (Thorup et al., 20162018).

As Table 1.1 suggests, these inconsistencies do not seem to reflect differences in the age of the participants. Some authors have suggested differences between studies may result from variation in the communicative content of the scene, with reduced looking in ASD particularly when the face addresses the child (Shic et al., 2014) or when it establishes mutual gaze (Nyström et al., 2017). One study has directly addressed the question of whether directed communication is particularly problematic (Vernetti et al., 2018).

In this study, toddlers could choose between animating (by looking at them) either a video of a person that established eye contact and directly addressed them, or a video of a spinning mechanical toy.

There was no difference between those with a later diagnosis of ASD and those without, with all groups choosing to animate and engage longer with the face rather than the toy. Those studies which have analyzed dwell time to the face during gaze following have also failed to find group differences (Chawarska et al., 2012Billeci et al., 2016Vivanti et al., 2017), suggesting that poor gaze following in ASD may not be due to insufficient engagement with faces.

During infancy and early toddlerhood, eye-tracking studies are consistent in suggesting that the ability to shift one’s gaze to follow someone else’s gaze direction to an object (henceforth referent) rather than an equally salient distractor, is intact in toddlers with ASD or infants with later ASD, with differences appearing to emerge later in development (see Table 1.2). There is, however, a more mixed picture when studies analyzed the dwell time on objects, with most studies finding decreased looking toward the gazed at objects, but a few finding no differences (see Table 1.3). Some of the inconsistency in findings may reflect differences in the way engagement with objects was measured.

Researchers either directly compared time spent on referent versus distractor or contrasted time spent on the referent to time spent on all areas of interest (AOI), including the face or the background.

While the former measure directly assesses an understanding of which object is the referent of the gaze, the latter measure also captures infants’ engagement with irrelevant aspects of the scene or differences in looking toward the face. However, no consistent associations between a certain way of measuring engagement with objects and later ASD emerges in this brief review.

The only previous study of infants at risk that looked at engagement with objects, found that infants who later developed ASD engaged less with the referent as compared to the whole scene but did not directly compare attention distribution between referent and distractor (Bedford et al., 2012).

TABLE 1.2

Direction of first look results from eye-tracking studies exploring joint attention using gaze following in young children with ASD or at-risk for ASD.

Direction of first look in response to gaze shifts
ArticleParticipantsMeasureASD vs. others1Additional information2
Bedford et al., 2012High-risk∗∗, LR 7 and 13 mo.R/(R + D + O + F)Same
Thorup et al., 2016High-risk, LR 10 mo.LIVE interaction (not screen-based)
R-DSameResponse to Eye + Head better than Eyes only for HR but not LR group
R-D/(R + D)SameBoth groups above chance
Nyström et al., 2019High-risk∗∗, LR 10 mo.R-DSameLIVE interaction (not screen-based)
This studyHigh-risk∗∗, LR 15 mo.(R-D)/(R + D)SameAll above chance
R/(R + D + O + F)Same
Billeci et al., 2016ASD, TD 18–30 mo.(R–D)/(R + D)SameChance comparison not reported
Gliga et al., 2012High-risk∗∗, LR 36 mo.R/(R + D)SameAll above chance
Falck-Ytter et al., 2015ASD, TD 41 mo.R-DSame
Vivanti et al., 2017ASD, TD 48 mo.R/(R + D)LessChance comparison not reported
SameAfter excluding trials with face dwell time during gaze shift < 100 ms
Gillespie-Lynch et al., 2013ASD, TD 28–79 mo.R-DLess
Thorup et al., 2017ASD, TD 38–115 mo.R/(R + D)SameAll above chance

OpeStudies are organized by participant age (youngest to oldest) to highlight any developmental progression. R, object referenced; D, distractor object; F, whole face area; O, other areas of screen. High familial risk studies without diagnostic outcome comparing LR with HR; ∗∗High familial risk studies with analysis by outcome. TD, typically developing; ASD, diagnosed. 1‘Less’ indicates ASD or high familial risk participants had lower values than typically developing/low familial risk participants. 2This column contains additional relevant information regarding experimental conditions or comparisons to chance (where appropriate).

Given that gaze following has been suggested as one of the sources of atypical language development in ASD, surprisingly few studies have measured gaze following in the context of word learning.

To address existing gaps in the literature and clarify the above inconsistencies in findings, the current study investigated visual behavior during a word learning task in a population of 15-month-olds with older siblings with ASD. We specifically asked whether atypicalities previously reported for infants later diagnosed with ASD reflect poor following or understanding of gaze direction, in which case we would find differences in measures directly comparing attention to the referent and the distractor; alternatively, they may reflect differences in attention distribution across the whole scene which may emerge when dwell time to the face or other parts of the screen are investigated.

To clearly distinguish these two sets of measures, we refer to the former as gaze following and the latter as attention distribution. In addition to comparing performance between the four outcome groups: low-risk controls (LR), high risk with typical development (HR-TYP), high risk with atypical development (HR-ATYP) and high risk with ASD (HR-ASD), we also investigated the association between experimental variables and continuous measures of ASD traits, language and developmental level.

This approach aligns with the recent shift away from the reliance on categorical diagnostic boundaries for research and a move toward the use of continuous measures characterizing individual domains of interest (Insel et al., 2010).

In summary, we predicted that:

  • (1)HR-ASD infants will show typical gaze following as measured by first look direction, evident as a significant difference between first looks to referent and distractor;
  • (2)HR-ASD infants will spend significantly less dwell time on the referent than the other groups;
  • (3)As a consequence of less dwell time spent on the referent, HR-ASD infants would show significantly poorer object-label mapping.

We were unable to make a clear prediction for dwell time on the face since previous studies have been equivocal, reporting both significantly less time and no differences.


Source:
Rutgers
Media Contacts:
Jennifer Forbes – Rutgers
Image Source:
The image is credited to Rutgers.

Original Research: Closed access
“Shared Reading at Age 1 Year and Later Vocabulary: A Gene–Environment Study”. Manuel E. Jimenez, Nancy E. Reichman, Colter Mitchell, Lisa Schneper, Sara McLanahan, Daniel A. Notterman.
The Journal of Pediatrics doi:10.1016/j.jpeds.2019.07.008.

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