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Texas State psychology professors and students study how and why youngsters lie

Research & Innovation

Julie Cooper | May 11, 2021

little girl whispering into another girl's ear

"The dog ate my homework."


Psychology professors Katherine Warnell and Jennifer Clegg research children’s development. In new work, they are studying how children learn to lie.

This research has resulted in a 2020 article in the Journal of Experimental Child Psychology (by Warnell and Texas State graduate alumna Callie De La Cerda) titled “Young children’s willingness to deceive shows in-group bias only in specific social contexts.” Warnell and Clegg and their students have also presented this work at the meetings of the Society for Personality and Social Psychology and the Society for Research in Child Development.

“Lying is a complex behavior. It requires sophisticated social cognition because you have to think about how others are perceiving you, what they know, and whether the lie is successful or not,” Warnell said.

The research looks at children between 4- and 10 years old. In pre-pandemic days, students and professors would spend weekends doing research as part of a program they developed in partnership with the city of San Marcos called Science in the Park. As part of this program, children participate in a study by playing games or solving puzzles. Through the Science in the Park program, the researchers conduct community outreach and increase diversity in children’s participation in scientific research to reflect the diversity in the San Marcos area. The researchers hope to resume the program soon.

researchers and young children at park
Since October 2019, the City of San Marcos Parks and Recreation Department and the Texas State University Department of Psychology have been in an ongoing partnership for child development research called Science in the Park. Warnell and Clegg hope to resume in-person events in the future after the COVID-19 pandemic put a halt on activities.

In their studies, Warnell and Clegg examine how children learn about different types of lies. One example is anti-social lying, like a child saying, “I didn’t eat the chocolate!” (even though their face is covered in chocolate). According to Warnell, these lies tend to show up early in development. One recent publication from Warnell and her research team finds complex anti-social lying in children as young as 4. Another type of lie is prosocial lying, or polite lies. Clegg said these lies are often used to avoid hurting someone’s feelings. For example, telling someone that their bad gift is great is a prosocial lie. Clegg explained that these lies are difficult for younger children.

By elementary age, children have learned when different types of lies are socially acceptable, but the professors agree that children don’t always react appropriately at holiday gift exchanges. That’s when parents may have to rehearse a polite thank you. “This is all the process of growing up and the process of parenting,” Clegg said, continuing, “It would be dishonest to say that we ever stopped lying. Lying is an important social tool that we use.”

Warnell and Clegg emphasized that it is very typical for preschoolers to lie and that lying is an important developmental milestone. “Lying is a hallmark of sophisticated social processing. It requires the kid to think about what you, as the adult, know and what you don’t know,” Warnell said. She further explained that lying is related to some other important social skills, like the ability to think about other people’s thoughts (theory of mind) and the ability to inhibit and self-regulate (executive function).

The researchers also talked about how there are differences in lying across cultures. “The acceptability of different kinds of lies is culturally-variable. For example, in the U.S. we take it for granted that we are going to tell each other polite lies,” Clegg said.  To compare cross-cultural differences in lying, Warnell and Clegg are working with researchers at Erasmus University Rotterdam in the Netherlands, where early work suggests that social norms related to polite lies are not always the same. Part of this project is to better understand the role of parents in teaching their children when different lies are appropriate.  

woman's headshot
Katherine Warnell
woman's headshot
Jennifer Clegg

For Texas State psychology students, this research is an opportunity to get direct experience working with families and with the scientific process. Students learn about survey creation and data analysis, using tools that can help them later in graduate school or the workplace.

“We want our Texas State students to feel empowered as scientists. Our work would not be possible without the amazing work of undergraduate and graduate students,” Clegg said.

The researchers note that their overall goal is to increase knowledge about how children develop. Warnell explained, “I like to say that not everyone is going to become a psychology professor, but most everyone will interact with a child.”

Further reading: Texas State Conducts Science Outreach in Local Parks

For more information, contact University Communications:

Jayme Blaschke, 512-245-2555

Sandy Pantlik, 512-245-2922