The team led by Stephanie Madon, an ISU associate professor of psychology found that mother's beliefs regarding her child's likelihood of using alcohol might have a strong impact on the kids' alcohol use in future.
They analysed data obtained from a series of interviews with nearly 800 Iowa mothers and their children over three to five years.
"When mothers overestimated their teens' future use of alcohol, the teens developed the self-view that they were likely to drink alcohol in the future, which ultimately led them to drink more," said Madon, also the study's lead author.
The team's previous research had found a link between a mother's belief about her child's likelihood of using alcohol and her child's actual use in junior high school and high school.
"We previously found that mothers' beliefs about their teen's future use of alcohol were about 50 percent correct and 50 percent incorrect, and that the incorrect portion of mothers' beliefs created a self-fulfilling prophecy -- teens behaved like their mothers had incorrectly expected them to," Madon said.
She said that the current study focuses on 'How is that happening? What are the mechanisms that are creating that?'
"We derived our hypothesis from three large, well-known theories in the social/psychological literature -- self-verification theory, research on conformity and social learning theory as it pertains to modelling processes," she said.
According to Madon, self-verification theory proposes that people are motivated to confirm what they already believe to be true about themselves.
The study found strong evidence that a mother's beliefs regarding her child's likelihood of using alcohol altered her child's self-view in either a positive or negative direction. The child then validated that new self-view by acting consistently with it later on.
"What people believe ultimately has an impact on what actually occurs," Madon said.
"But it's not just because they believe it. It's not magic. When we believe something -- even if we're wrong -- when we believe it's true, we act as though it is. And sometimes when you act as though something's true, your behaviours will cause the belief to become true.
"So I think the moral here is to help children develop positive and pro-social self-concepts about themselves, because children are likely to make choices that match how they view themselves," she added.
Madon said that it's still a good idea for mothers to instill in their children the belief that adolescent alcohol use is unacceptable, since the study did show a direct effect of teens' perceptions regarding the acceptability of alcohol use on their own drinking.
The study appears in the Journal of Personality and Social Psychology.