Parents say that honesty is the best policy, but they regularly lie to their children as a way of influencing their behaviour and emotions, finds new research from the University of Toronto and the University of California, San Diego.

Surprisingly little scholarship has been published on the subject of parental lying, so Gail Heyman, professor of psychology at UC San Diego, Diem Luu, a former UCSD student, and Kang Lee, professor at the University of Toronto and director of the Institute of Child Study at OISE, set out to explore the under-researched phenomenon. They asked U.S. participants in two related studies about parents lying to their children – either for the purpose of promoting appropriate behaviour or to make them happy.

In one of the studies, many parents reported they told their young children that bad things would happen if they didn't go to bed or eat what they were supposed to. For example, one mother said she told her child that if he didn't finish all of his food he would get pimples all over his face. Other parents reported inventing magical creatures. One explained, "We told our daughter that if she wrapped up all her pacifiers like gifts, the 'paci-fairy' would come and give them to children who needed them...I thought it was healthier to get rid of the pacifiers, and it was a way for her to feel proud and special."

In the other study, the researchers surveyed college students' recollections about their parents' lying and obtained similar results: parents often lie to their children even as they tell them that lying is unacceptable.

The researchers refer to this practice as "parenting by lying." "We are surprised by how often parenting by lying takes place," said Lee. "Moreover, our findings showed that even the parents who most strongly promoted the importance of honesty with their children engaged in parenting by lying."

Though Heyman thinks that there are occasions when it is appropriate to be less than truthful with a child – "telling a two-year-old you don't like their drawing is just cruel," she said – she urges parents to think through the issues and consider alternatives before resorting to the expedient lie.

"Children sometimes behave in ways that are disruptive or are likely to harm their long-term interests," said Heyman. "It is common for parents to try out a range of strategies, including lying, to gain compliance. When parents are juggling the demands of getting through the day, concerns about possible long-term negative consequences to children's beliefs about honesty are not necessarily at the forefront."

The research also examined "parenting by lying" among Asian-American and European-American parents. Asian-American parents were more likely to report lying to their children for the purpose of influencing their behaviour. According to the researchers, one possible explanation for this finding is that as compared to European-American parents, Asian-American parents tend to place a greater emphasis on the importance of teaching children to be respectful and obedient, and they use a range of parenting strategies to meet these ends.

The research is published in the current edition of the Journal of Moral Education and was supported by a grant from the National Institute of Child Health and Human Development.

Heyman and Lee are now preparing an international study to explore the subject further, and they are also beginning to study the possible consequences of "parenting by lying": Does it create confusion about right and wrong? Does it undermine a child's trust?