Researchers have found that children aged 3 to 5 who were tested both before and after the COVID lockdowns displayed a notable decline in a fundamental cognitive ability. This effect was particularly pronounced among kids from financially disadvantaged homes and those with less-educated parents. This research is among the first to highlight the cognitive impact of the pandemic on children who had not yet begun formal schooling.
The COVID-19 pandemic brought about lockdowns, social distancing, and the closure of schools and businesses, which sparked a wave of studies focusing on its effects on school-age children. Researchers aimed to understand how students’ academic performance, mental health, and social development were influenced by these disruptions.
However, little attention was paid to how preschool-aged children—those under 6 years old—might be affected by the pandemic, given that their day care centers closed, and families stayed home.
This changed when a research team from UC Merced, which had been collecting data before the pandemic, discovered that children’s performance in a crucial cognitive skill—false-belief understanding—was significantly impacted. This decline was especially noticeable among children from families with lower financial resources and parents who had less education.
“The drop in performance was astonishing,” remarked Professor Rose Scott, a developmental psychology expert and the lead author of the study published in Scientific Reports. “Children who were tested prior to the pandemic could pass a specific task as early as 2 and a half years old. Yet after the lockdowns, even 5-year-olds struggled with it.”
The UC Merced team, which included graduate students Gabriel Nguyentran and James Sullivan as co-authors, assessed children’s social cognition regarding false-belief understanding—the ability to recognize that others can hold incorrect beliefs. This skill is essential for distinguishing between one’s own thoughts and the reality of others, contributing significantly to social cooperation, communication, and learning.
A total of 94 children were included in the initial testing. Each child completed three false-belief tasks. In one scenario, a child observed a puppet named Piggy placing a toy in one of two containers and then leaving the stage. A second puppet then moved the toy to the other container. When Piggy returned, the child was asked where Piggy would look for the toy. A well-developed false-belief understanding would lead the child to answer that Piggy would look in the first container, despite knowing the toy was not there.
Research indicates that the development of false-belief understanding is crucial during the first five years of a child’s life. According to Scott, a child who lags in cognitive skills might struggle to get along with peers or face challenges in educational tasks as they grow.
“Consider what children need to do to interact in a classroom. They desire friendships but must also consider different perspectives to engage socially effectively,” she explained. “For instance, they might think, ‘I understand you want to play with this toy now, but I really want to play with something else.’ They need to hold both viewpoints while interacting.”
For example, in the earlier task, 80% of the 5-year-olds in the pre-lockdown group were able to pass. However, in the post-lockdown group, only 63% succeeded, and among 5-year-olds from lower-income families, this dropped to just 51%—essentially a random guess, as Scott noted.
They assessed the children’s language abilities and measured their family’s socioeconomic status based on total household income over the previous year and the highest educational level reached by either parent. The first round of testing occurred from August 2019 to March 2020, during which the pandemic began. A second group, statistically comparable, was tested starting in September 2021.
Results showed that children in the post-pandemic group, particularly those from lower socioeconomic backgrounds, demonstrated a marked decrease in cognitive abilities compared to the pre-pandemic group. In contrast, those from more affluent homes showed minimal cognitive setbacks from the lockdowns.
What accounts for this disparity among lower socioeconomic status children? The study doesn’t provide a conclusive answer, but Scott suggests that the shutdown of formal day care and playdates, coupled with the financial and mental pressure on lower-income parents, may have led to reduced communication with their children. This could result in increased passive screen time, which has been associated with diminished false-belief understanding.
Follow-up tests conducted in 2023 on some members of the post-pandemic group revealed concerning findings. The lower scores in false-belief understanding persisted, continuing like an ongoing wave, according to Scott.
In March, Scott shared these important findings at a conference in Pasadena, where attendees took notice. Interest in this topic intensified following the study’s publication in November.
“Whenever I present this information, colleagues in my field express their surprise and agreement with our findings,” Scott stated. A fellow researcher from another university reached out in December to say that the UC Merced research clarified many observations within their own studies regarding children’s social cognition after the pandemic.
“I suspect more research exists on this matter, but people haven’t thought to investigate the impact on children before they start school,” Scott concluded.
