High rates of screen time linked to specific differences in toddler vocabulary

New research published in the journal Developmental Science provides evidence that the amount of time toddlers spend watching videos is associated with the specific types of words they learn, distinct from the total number of words they know. The findings indicate that higher levels of digital media consumption are linked to a vocabulary containing a smaller proportion of body part words and a larger proportion of words related to people and furniture.

The widespread integration of digital media into family life has prompted questions about its influence on early child development. Current estimates suggest that many children under the age of two spend roughly two hours per day interacting with screens, primarily watching videos or television.

Previous research has often focused on the relationship between screen time and the overall size of a child’s vocabulary. These earlier studies generally established that high exposure to low-quality programming correlates with a lower total number of words spoken by the child.

However, language acquisition is a multifaceted process. Children do not learn all words in the same manner. The acquisition of certain types of words relies heavily on specific environmental inputs.

“There is no doubt that use of digital media by young children has been on the rise in the past few years, and growing evidence suggest that this has impacts on their language learning, especially during the first few years of life,” said study author Sarah C. Kucker, an assistant professor of psychology at Southern Methodist University.

“For instance, we know that children who watch high rates of low-quality television/videos tend to have smaller vocabularies and less advanced language skills (this is work by my own lab, but also many others such as Brushe et al., 2025; Madigan et al., 2024). However, we also know that some forms of media do not have negative effects and can, in fact, be useful for language when the media is high-quality, socially-interactive, and educational in nature (work by Sundqvist as well Jing et al., 2024).”

“On top of this, we know that children’s language development and specifically their vocabulary learning is not an all-or-nothing, but rather that children learn different types of words at different times and in different ways – e.g. learning words for body parts is easier when you can touch the body part when named, and names for people (mama, dada) are learned earlier than most other nouns,” Kucker continued.

“When we put this together it means that we shouldn’t be looking at digital media’s influence on language as just an all-or-nothing, or blanket good-or-bad, but rather take a more nuanced look. So we did just that by looking at the types of words children are learning and the association with the time they spend with digital media.”

For their study, the researchers recruited 388 caregivers of children aged 17 to 30 months. This age range represents a period of rapid language expansion often referred to as the vocabulary spurt. Participants were recruited through online research platforms and in-person visits to a university laboratory. The researchers combined these groups into a single dataset for analysis.

Caregivers completed a comprehensive survey known as the Media Assessment Questionnaire. This instrument asked parents to report the number of minutes their child spent using various forms of technology, such as television, tablets, and video chat.

The researchers collected data for both typical weekdays and weekends. They used these reports to calculate a weighted daily average of screen time for each child. The data revealed that video and television viewing was the most common media activity. On average, the children in the sample watched videos for approximately 110 minutes per day.

To measure language development, caregivers completed the MacArthur-Bates Communicative Development Inventory. This is a standardized checklist containing hundreds of words commonly learned by young children. Parents marked the words their child could say.

This tool allowed the researchers to calculate the total size of each child’s noun vocabulary. It also enabled them to break down the vocabulary into specific semantic categories. These categories included animals, vehicles, toys, food and drink, clothing, body parts, small household items, furniture and rooms, outside things, places to go, and people.

The researchers also analyzed the vocabulary data through a different lens. They classified nouns based on the features that define their categories. Specifically, they looked at shape-based nouns and material-based nouns.

Shape-based nouns usually refer to solid objects defined by their physical form, such as “ball” or “cup.” Material-based nouns often refer to nonsolid substances or items defined by what they are made of, such as “applesauce” or “chalk.” This distinction is significant in developmental psychology because physical handling of objects is thought to help children learn these concepts.

The researchers found that children with higher rates of video viewing produced a smaller proportion of body part words. In a typical toddler’s vocabulary, words like “nose,” “feet,” or “ears” are often among the first learned. However, as screen time increased, the density of these words in the child’s repertoire decreased relative to other word types.

In contrast, the researchers found a positive association between video time and words related to people. This category includes proper names, titles like “teacher” or “grandma,” and general terms like “baby.” Children who watched more videos tended to have a vocabulary composition that was more heavily weighted toward these social labels.

A similar positive association was found for the category of furniture and rooms. Heavy media users were more likely to produce words such as “couch,” “TV,” or “kitchen” relative to their peers with lower media use.

“While we expected that children with high media use would have fewer body part words in their vocabulary, we were surprised to find that children with high media knew relatively more people words and furniture words,” Kucker told PsyPost. “We suspect this may have to do with the content of the media highlighting those terms, or perhaps the physical context in which children are using media (e.g. while sitting on a couch or when working with mom), but the tools to capture this information are currently limited.”

The researchers found no significant relationship between video watching and the other semantic categories measured, such as animals, toys, or food. Additionally, the researchers found no evidence that video exposure altered the balance between shape-based and material-based nouns. The proportion of words related to solid objects versus nonsolid substances remained stable regardless of screen time habits.

The research highlights that the impact of digital media is not uniformly negative or positive. The findings suggest that screen time changes the landscape of early learning in specific ways.

“Most caregivers have heard the advice to avoid screen time with their young children,” Kucker said. “However, the reality is that that is very difficult to do 100% of the time in today’s tech-based world. What this study shows is that a high amount of low-quality videos/TV is associated with lower overall vocabulary sizes in 2-year-old children, but that that videos/TV may not impact all types of words equally.”

“For instance, children with more video/TV time have fewer names for body parts, but seem to learn most other nouns at relatively equal levels, potentially because some videos/TV do a good job teaching children some basics.”

“So do try to limit children’s screen time, but don’t fret about avoiding it completely,” Kucker explained. “Instead, consider the content and context for when the media is being used and why – high-quality, educational use, or those that are social (e.g. FaceTime, Zoom), may not be detrimental as long as children are still getting rich interactive play outside of the screen.”

As with all research, there are some limitations to consider. The data relied on caregiver reports, which can introduce memory errors or bias.

The study was also cross-sectional, meaning it captured a snapshot of the children’s lives rather than following them over time. It is not possible to determine causality from this data alone. For example, it is unknown if watching videos causes the change in vocabulary or if families with different communication styles rely more on media.

“We are currently looking at more longitudinal impacts of digital media on children’s language over time as well as individual differences across children, such as considering personality and temperament,” Kucker noted.

Additionally, the study focused primarily on the duration of screen time. It did not fully capture the specific content of the videos the children watched or the nature of the interactions parents had with their children during viewing. The researchers noted that educational content and co-viewing with a parent can mitigate potential negative effects.

“Not all media is bad!” Kucker said. “Media’s effect on children is nuanced and interacts with the rest of their experiences. I always like to tell parents that if your child watches an educational show for a few minutes so you can have a few minutes of quiet, that may be helping you to then be a better parent later which will more than offset that few minutes of media time.”

“Children who get rich, social experiences are often still developing in very strong ways even if they have a bit of high-quality screen time here and there. Just considering the content and context of the media is key!”

“We have a lot of work left still to do and understand in this area, and much of the support for this work has come from various grants and foundations, such as NIH and NSF,” Kucker added. “Without those funding avenues, this work couldn’t be done.”

The study, “Videos and Vocabulary – How Digital Media Use Impacts the Types of Words Children Know,” was authored by Sarah C. Kucker, Rachel F. Barr, and Lynn K. Perry.