1 Introduction
Children’s language development is an essential early skill related to children’s socio-emotional development (Clegg et al., 2015) and academic success (Fiorentino and Howe, 2004). Children’s language development is strongly linked to the language they hear in their everyday environments both in terms of the quantity and the quality of the language experienced (Hart and Risly, 1995; Hoff and Naigles, 2002; Huttenlocher et al., 2010; Rowe, 2012; Weisleder and Fernald, 2013). For today’s child, language development is both supported and hindered by digital technologies in their environment (Madigan et al., 2020; Kolak et al., 2023; Taylor et al., 2018). In this study, we investigate the conditions under which use of digital technology may provide an additional support to children’s language development, in particular, in their acquisition of new vocabulary. Specifically, we test how verb learning may be supported by children using an app that they direct themselves vs. using an app in co-use with an adult, and comparing learning from those situations with children learning the same words in a live interaction with an adult.
While educational digital technologies provide an opportunity to hear language that could support children’s language development (Kolak et al., 2023), studies also demonstrate that parent media use may disrupt language development. Specifically, parent language is negatively impacted by the presence of background television (Christakis et al., 2009; Kirkorian et al., 2009; Pempek et al., 2014), and mobile device use during parent-child interactions can disrupt word learning altogether (Reed et al., 2017). More recently a naturalistic study conducted in children’s homes found a negative association between background television and parent-child interactions playing with a toy together and a positive association with infants’ individual activities (Uzundag et al., 2024).
In a meta-analysis, Madigan et al. (2020) found that while children’s overall screen use—defined as time spent watching television, playing video games, using touchscreen devices or computers—was negatively related to their language scores, educational content and adult-child co-use was positively related to children’s language scores. More recently, Jing et al. (2023) found a small positive correlation between children’s digital media exposure and their vocabulary scores in experimental studies with educational media designed to support children’s vocabulary learning. Thus, children’s educational digital technology use has the potential to enrich a child’s language development when used alongside other forms of interaction known to support language development (Taylor et al., 2018).
Children’s touchscreen apps may be particularly well suited to supporting children’s language development due to their interactive and contingent nature facilitating learning in a similar way to a social partner (see Kirkorian, 2018 for review). Apps with a learning goal targeting early skill development can also engage a child’s attention and promote active learning and problem solving, provide specific feedback relating to a child’s performance, scaffold the content to align with a child’s performance on a given task (e.g., making a task more or less difficult) and expose children to a wide range of vocabulary (see Hirsh-Pasek et al., 2015; Kolak et al., 2021, 2023 for similar arguments). Research shows that apps with a learning goal include more utterances including single and multi-word utterances, words with an earlier age of acquisition, and contain lower frequency words similar to books compared to apps without a learning goal (see Kolak et al., 2023; Taylor et al., 2022). Apps therefore have the potential to provide an enriched form of language input for young children.
Indeed, studies demonstrate that pre-school age children can learn new words from touchscreen apps (e.g., Ackermann et al., 2020; Arnold et al., 2021; Chiong and Shuler, 2010; Dore et al., 2019; Kirkorian et al., 2016; Russo-Johnson et al., 2017; Walter-Laager et al., 2017). Dore et al. (2019) found that 4-year-olds could learn uncommon words (4 concrete nouns, 4 verbs, and 2 abstract nouns) from an experimental app when tested immediately after using the app for just 10-12 min or after using the app once a week for 4 weeks in the classroom. Using the Khan Academy Kids app available in the app marketplace, Arnold et al. (2021) found that over a 10-week period 4- and 5-year-old children using the app for around 13 min per day showed subsequent gains in literacy skills.
However, research to date has primarily focussed either on broad gains in language skills (e.g., Arnold et al., 2021; Chiong and Shuler, 2010) or on children’s ability to learn specific nouns from an app (e.g., Kirkorian et al., 2016; Russo-Johnson et al., 2017; Walter-Laager et al., 2017, with the exception of Dore et al., 2019). Word learning encompasses more than just acquisition of nouns, it is also important to consider other major classes of word type including children’s ability to learn verbs, adjectives and adverbs. Although Dore et al. (2019) included exposure to 6 nouns and 4 verbs in their study, they did not distinguish between children’s ability to learn the nouns and verbs from the touchscreen app. This is a particularly important question given that children learning the English language typically acquire nouns before verbs (Waxman et al., 2013; but note that this is not the case in other languages e.g., Tse et al., 2005). There are several reasons for this greater apparent difficulty in acquiring verbs. Verbs have less reliable contexts with other words in utterances than do nouns (Gleitman, 1990; Monaghan et al., 2015), meaning that distributional information for verbs is weaker than for nouns in English. In addition, verbs are conceptually less coherent than nouns, in that verb referents are dynamic and transient, whereas noun referents tend to be more stable within the child’s environment (Childers and Tomasello, 2002; Gentner, 1982; Gillette et al., 1999), potentially requiring greater contextual information to support learning of verbs than nouns (e.g., Arunachalam and Waxman, 2011). Touchscreen apps may be advantageous for verb learning because they can display dynamic actions and provide a useful environment where transience and ambiguity in verb reference can potentially be controlled. Thus, understanding how apps can promote verb learning is important for determining the full range of language support available from different kinds of exposure.
Another form of digital exposure is learning through interaction with an interlocutor through technology-mediated communication, such as video chats. Roseberry et al. (2009) found that 2.5-year-old children could learn verbs from a video only when the video was accompanied by a live adult imitating the actions, while 3-year-old children showed some evidence that they could learn verbs from video alone. In a follow up study, Roseberry et al. (2014) explored the role of social contingency in supporting 2.5-year-old children’s verb learning from screens. Two and half-year-old children were shown novel actions labeled either during a live interaction, a socially contingent onscreen interaction (via Skype) or via a yoked video of the socially contingent onscreen interaction. The children learnt the novel verbs in the socially contingent conditions only and showed no evidence of learning if they saw the yoked video (Roseberry et al., 2014). Roseberry et al. (2014) suggest that social contingency is important when learning from digital media to establish trust between the child and teacher, given that the researcher is able to respond accurately to the child’s responses and cues. In a similar way, touchscreen apps may offer a form of contingency in response to children’s touch, though digital contingency lacks the same social component present in Roseberry et al. (2009, 2014)’s research. The contingency offered by touchscreen apps and their interactive nature may therefore be a help in supporting children’s verb learning.
Along with the paucity of research on children’s verb learning from touchscreen apps and other digital media, there have been few studies exploring the role of adult-child co-use on children’s word learning from apps. American Academy of Pediatrics (2016) recommend parent-child co-use during children’s media use whereby parents interact with their children about the digital content. Consistent with this recommendation, a recent meta-analysis with 17 eligible studies found a small but significant positive effect of co-viewing on children’s learning across several learning domains (Taylor et al., 2024). Approximately half of the studies included in the meta-analysis included the experimenter as the adult-co-user, and the person co-using the digital media with children did not moderate the significant positive effect of co-viewing (Taylor et al., 2024). However, the majority of studies used video or television for the digital content (Taylor et al., 2024). Adult-child co-use can support children’s learning through increasing children’s attention to the digital content (Samudra et al., 2020). In their study, Samudra et al. (2020) found that 3- to 4-year-old children’s comprehension of a video was associated with adult-child co-use, attention to the video and their language skills.
Adult-child co-use may be particularly beneficial for children’s word learning given the social nature of children’s language learning. For example, Strouse et al. (2018) found that 2.5-year-old children learnt more words from a socially contingent facetime video chat in a parent co-use condition compared to when the parent was engaged in another activity during the word learning task. In that study, parents were instructed to interact with the adult onscreen to set an example for their child rather than specifically directing the child’s interaction with the onscreen actor. However, some research suggests that parents are less likely to engage with their children during children’s app use compared to toy play, perhaps explained by apps requiring continuous attention and the fact that children spent the majority of their app use with the tablet on their lap (Hiniker et al., 2018). Indeed, Connell et al. (2015) found that approximately 64% of parents of 0-8-year-olds co-use touchscreen devices with their children “some of the time” or “all or most of the time.” A systematic review by Ewin et al. (2021) found that parents engage in many forms of support during mobile device co-use such as interacting only when asked for help, supporting understanding and engagement with the content, and providing physical and technical support.
Understanding what constitutes effective parent-child co-use techniques to facilitate learning is also important since caregivers engage in various forms of co-use behaviors (Ewin et al., 2021). Neumann (2018) found that parents most frequently use cognitive scaffolding (e.g., helping children solve problems) to support 2-4-year-olds on a touchscreen rather than technical scaffolding (e.g., telling children how to use the app). In contrast, Griffith and Arnold (2019) found that parents talked more about the app (e.g., app features or how to interact with the app) compared to the apps’ literacy and math content when using an app with their 4-year-olds. In relation to children’s learning outcomes, Sheehan et al. (2019) found that parents’ task relevant talk during a coding app was positively related to 4-year-old children’s learning, while parents’ questions were negatively related to children’s learning. Importantly, these observational studies cannot reveal what aspects of adult-child co-use facilitate children’s learning.
A couple of studies have started to investigate the role of parent-child app co-use on children’s learning outcomes. In one study exploring whether co-use can improve children’s ability to learn coding skills from an app (Griffith et al., 2022), 4- and 5-year-old children either played a coding app independently, with their parent, or played a coloring app with their parent. Overall, children who played the coding app showed an improvement in their coding skills compared to pre-test, with the greatest improvement in coding skills found for children who played the app with their parent rather than independently (Griffith et al., 2022). Similarly, Walter-Laager et al. (2017) found that 2-year-old children played with a touchscreen app for longer when using the app together with an adult compared to using the app independently. In addition, children who used the touchscreen app with an adult showed the greatest improvement in their knowledge of 12 nouns presented on the touchscreen app compared to children who used the app without an adult (Walter-Laager et al., 2017). Consistent with findings for parent-child co-use during video viewing (e.g., Strouse et al., 2018), parent-child co-use during app use is beneficial for children’s learning (Griffith et al., 2022; Walter-Laager et al., 2017). Nevertheless, to date, no study has directly manipulated co-use for children’s touchscreen apps to explore the impact on verb learning, where the dynamics of the referent and contextual information tend to be very different to those for noun learning.
In the current study we asked whether children can learn verbs from touchscreen apps under child-led or adult-led co-use conditions, and in a live condition. Three-year olds were shown three novel verbs either on an app where the child led the app interaction or where the experimenter led the app interaction, or in a live interaction with the experimenter. Each novel verb was presented four times; twice in isolation and twice in intransitive sentences, and children were given the opportunity to watch a video clip in which the action was demonstrated. Verb learning was tested on the touchscreen tablet using a three-choice pointing task using the same images from the app conditions. Given that Naigles et al. (2005) showed that by 2 years of age, children can transfer novel verbs learnt in a live interaction to videos, we hypothesized that children in the live condition would perform above chance on the verb learning test. We therefore hypothesized that any difference in test performance between the live and app conditions would result from differences in learning. Children under the age of 3 years can only learn a novel verb from a video if it is supplemented with live interaction (Roseberry et al., 2014, 2009). Thus, we hypothesized that children in the child-led app condition would not show evidence of learning, while children in the adult-led app condition would show evidence of learning. Note that the age we selected is at the cusp of beginning to be able to learn verbs with and without social scaffolding (Roseberry et al., 2009) and so potentially able to highlight distinctions between learning from apps vs. live interactions.
