individual differences + language interventions

when do most children start producing their first words (Fenson et al., 1994)

within a few months of their first birthday → 10-15 months, though there are enormous individual differences in the rate of learning within this

what did Fenson et al. (1994) find when mapping out individual differences in vocabulary size → number of words understood

by 16 months:

• the bottom 10% of children may understand less than 100 words

• children within the median will understand around 150 words

• those in the 90th percentile may understand around 350 words

shows huge individual differences

what did Fenson et al. (1994) find when mapping out individual differences in vocabulary size → number of words able to be produced

by 16 months:

• bottom 10% of children may produce less than 10 words (though this is not uncommon)

• median children would produce around 40 words

• those in the 90th percentile may produce around 180 words

once again indicates huge individual differences

how did Thornton et al. (2026) investigate individual differences in language on later educational outcomes

performed a millenium cohort study with around 15,500 participants → tracked likelihood of passing GCSE maths, English + science at 16 as a function of:

• age 5 vocabulary/language ability

• socioeconomic quintile (takes into account caregiver educational status, neighbourhood characteristics etc.)

what were Thornton et al. (2026)’s 3 findings in terms of individual language differences on later educational outcomes + what does this suggest

• found that when controlling for socioeconomic status, as vocabulary at 5 increases, the percentage of achieving benchmark academic qualifications also increases

• as each quintile of SES increases, the likelihood of achieving qualifications increases → even if vocabulary is good quality when they start school, those with lowest SES still only have around 50% chance of achieving benchmark qualifications

• there is a slight interaction between vocabulary + outcomes in the middle quintile → suggests SES has less effect on those of middling status on later attainment than those of lower/higher

overall shows that both vocab + SES predict later outcomes → encourages development of language skills to buffer effects of low SES

what 3 factors explain individual differences in language development

• infant’s prelinguistic communication predicts transition to language

• caregivers’ responsiveness to infants predicts language

• socioeconomic circumstances → more distal factor associated with vocabulary developmetn

what is the main idea of Bronfenbrenner (1979)’s ecological systems theory + its 3 layers

based on ecology → the study of interactions among organisms + their environments. posits that human development involves interaction between the person + properties of the immediate settings they grow up in, as well as the larger contexts these systems are embedded in.

• doesn’t suggest that humans are ‘blank slates’, but actively move into + restructure the environment they are in → mutual relationship

• overall posts that parent-child relationships do not exist in a vacuum → many different environmental factors influence language development

what are the 3 layers involved in Bronfenbrenner (1979)’s ecological systems theory

the model involves different systems of influence nested in one another:

• mesosystem → individual’s inner circle, so immediate contacts we interact with everyday e.g. family, peer group, classroom, religious setting

• exosystem → wider cultural/environmental factors impacting everyday environments, e.g. school/medical systems, media + community

• macrosystem → even wider factors impacting exosystem, e.g. economy, social conditions, political philosophy/customs, cultural values

what 3 main outcomes are socioeconomic circumstances associated with

• caregiver language

• child language

• child life outcomes

what is the social gradient found in language development

the correlation between children’s language skills and the SES they grow up in → the lower their SES, the more challenges with language skills they will typically face

what did Akhtar + Jaswal (2013) state about cultural differences in language development

cultural differences = part of life’s rich tapestry → it is not sensible to say we ‘should’ talk to children in a certain way if we respect cultural diversity, as differences in language development depending on culture are not always deficits

• however, within a society where long-term well-being depends on language skill (e.g. stable occupation, academics), social inequality needs to be addressed

how did Thornton et al. (2026) measure the influence of SEC and vocabulary, what 6 measures of SEC did they use + what was found

same study mentioned previously → children were tested at ages 3, 5, 11 + 14 on measures of SEC including:

• parental education

• (highest household) income

• parental wealth (assets e.g. house value)

• parental occupation

• index of neighbourhood deprivation by postcode

• composite (combination of all 5 measures)

found as measures of SEC increased, vocabulary scores increased linearly, with education, income + neighbourhood deprivation having the largest contributions

what did McGillion et al. (2017) find the relationship was between SEC and caregiver contingent talk

found a weak positive correlation between SEC and caregiver contingent talk (talk based on what a child is focussing on) → as SEC increased, the more talk increased also

• however there were many outliers → not a strong correlation

what are 2 factors proposed to be responsible for why social gradients exist

• psychosocial factors → more stress caused by economic tension leads to less time able to be spent aiding children’s language development

• cultural factors → some families that are middle class may have more pedagogical sounds (may use more ‘teachy’ tone/language that is easier to comprehend)

what 2 ethical considerations in the BPS code of ethics make it difficult to conduct research on social gradients

• respect → dignity of recognising the inherent worth of all human beings regardless of perceived/real differences in social status, ethnic origin or other such group-based characteristics

• social responsibility → need to support + reflect respect for the dignity + integrity of social groups, and contribute to the common good

essentially means it is important to not misconstrue findings to compound any stereotypes + apply differences found to promoting child development

why are poor language skills considered a public health problem (Law et al., 2013)

language skills are important to development + wellbeing, and them being poor can cause poor child outcomes due to problems accessing academics, employment, health services + positive social environments

how strong is evidence of efficacy of early parenting interventions on child language development

evidence is currently equivocal (equally for + against) → many plausible interventions have been raised but tests of reliability are not often performed

what is efficacy

how effective an intervention is in ideal circumstances → e.g. outcomes of an early parenting intervention in a lab experiment

what is effectiveness

how effective an intervention is in real-world circumstances → e.g. outcomes of intervention carried out in a nursery + long-term effects

what are 3 main methods of testing interventions + what are they useful for

• RCTs + meta-analyses → gold-standard methodological techniques used to assess efficacy + effectiveness of interventions

• qualitative work, correlation studies + lab-based experiments → can be used to check what the underlying mechanisms of interventions are

• pilot interventions → used to test feasibility + acceptability of interventions (interventions need to be both effective + likely to be used by parents)

what is contingent talk + what did McGillion et al. (2017) find when implementing this as an early-parenting intervention

child-directed speech that is contingent on infant’s focus of attention → found good longitudinal evidence of association with later vocab + experimental evidence to demonstrate how it promotes learning

what is an example of pedagogical language that can be used towards infants

parent using speech to try and teach infant something about the object they are interested in, rather than just conversational speech

how did McGillion assess the effectiveness of a contingent talk intervention on infant vocabulary

sample of 142 socially-diverse Sheffield-based caregivers + 11-month old infants were randomly assigned to either:

• contingent talk intervention

• dental health intervention → promoting interest in child interaction may have been confounding variable, so no other language intervention was used

intervention measures were assessed at 11, 12, 15, 18 + 24 months

what was McGillion et al. (2017)’s contingency intervention used + what effect did it have on caregiver-contingent talk

showed caregivers a short video identifying ways that infants indicate what they are interested in + examples of contingent talk, and were asked to set aside 15 mins a day to practice contingent talk. found intervention had modest but meaningful effect on the way parents talk:

• effect size of word types used = .27,

• effect size of % contingent words used = .35

what effects did McGillion et al. (2017)’s intervention have on infant vocabulary from families with lower SES

found when followed up at 18 months, infants in the intervention condition had their vocabulary grow 10.57 words a month, in comparison to 6.64 words/month in control condition

• found no effect for higher SES children → shows that contingency talk interventions can possibly close the gap between those with low + high SES

what were the 5 measures of child language used in the follow-up stages of McGillion et al. (2017)’s study

• communicative development inventories (CDI) → parent report of vocab

• naturalistic vocabulary count → tests knowledge of word types

• Reynell → standardised test of vocab

• ERB → standardised test of more general academic areas

• LENA → measures automatic speech recognition

what effects did McGillion et al. (2017)’s intervention have on child language at 24 months + what does this suggest

found no significant effect of the contingency talk intervention on child language at 24 months using all measures of vocabulary → suggests interventions apply early in childhood, but child eventually returns to individual trajectory based on baseline SES, caregiver contingent talk + infant communication

• implies that older child/teenager interventions may benefit from sustained support instead

how do McGillion et al. (2017) define contingency talk + what 3 things has this been previously found to be related to

a style of communication where a caregiver talks about what is in the infant’s current focus of attention → this has been found to:

• partially mediate associations with child word learning, especially in infants under 18 months who cannot yet redirect attention to interpret others’ communicative intentions

• result in substantially larger vocabularies as toddlers

• be less commonly used in less educated mothers, suggesting similar quality of child-directed speech is on a social gradient

what were the 5 inclusion criteria used in McGillion et al. (2017)’s study

infants are:

• first-born

• singleton (not part of a twin pair)

• birth weight over 2.5kg

• monolingual

• raised as English-speaking

what were the 3 exclusion criteria used in McGillion et al. (2017)’s study

• infant was born more than 3 weeks premature

• primary caregiver worked more than 24 hours a week

• infant/primary caregiver had disability preventing participation

how were SECs measured in McGillion et al. (2017)’s study

using the English Indices of Deprivation → based on neighbourhood employment, income, health provision + housing

• sample used in the study spanned all deciles of this measure → socially diverse

this was combined with primary caregiver education + income to collapse onto a single factor → SES

what occurred in the baseline (first) visit in McGillion et al. (2017)’s study

questionnaire pack was given out → audio recorders were given to participants in order for them to make 2 recordings

• gaze following test was conducted

• caregiver + infant were video-recorded together in free play for 30 minutes to provide measure of quality/quantity of caregiver talk + infant vocalisations

participants were then randomly assigned to intervention or control

when does McGillion et al. (2017)’s study suggest the social gradient in language ability emerges

around 24 months for British infants → when intervention effects drop off