URBANA, Ill. (U.S.A.) — When a baby begins to cry, do you expect its caregiver to soothe it? Most infants do, according to a new study from researchers at the University of Illinois Urbana-Champaign. The study also found an association between the mental health of mothers and infants’ expectations about comforting behavior.

“Even before infants can speak, they hold expectations about positive caregiving experiences,” said Kexin Hu, lead author of the study and a doctoral student in the Department of Human Development and Family Studies (HDFS), part of the College of Agricultural, Consumer and Environmental Sciences at Illinois.

To determine this, the researchers first showed more than 75 infants a series of videos of a woman performing household chores to familiarize the infants with the setup. Then, the infants saw two test videos: in the “ignore event,” a baby cried, and the woman continued with the household chores, whereas in the “comfort event,” the woman went to comfort the baby.

By measuring how long the infant looked at each test event, the researchers could determine whether the “ignore event” surprised the infants. It relies on a classic infant cognition paradigm — violation of expectations — which determines that an infant will look longer at an unexpected or surprising stimulus than at an expected one.

“If they look longer at the unexpected event, it suggests they are trying to figure out what is happening,” said Nancy McElwain, co-author and research professor in HDFS. “They are surprised, because there’s a violation of expectations. In the same way infants show surprise when an object defies a law of physics — such as floating in the air or moving through solid surfaces — they expect a caregiver not to ignore a crying baby.”

Infants were tested at 6, 9, and 12 months to determine consistency of the findings across different periods in the first year. At all three time points, infants registered more surprise at the “ignore event,” as indicated by longer looking times, than at the “comfort event.”

Mothers also completed a well-established questionnaire to assess their depressive symptoms.

“At each time point, more depressive symptoms reported by mothers were associated with their infants’ lower expectations about comforting behaviors,” Hu said.

Essentially, the team found that these infants were less surprised when the caregiver did not comfort the crying baby — a change from the pattern found in infants whose mothers showed few or no depressive symptoms.

“It’s plausible that most infants, from very early in life, hold nascent positive expectations for interpersonal interactions, including that a caregiver will comfort a crying baby,” McElwain said. “But over time, those expectations can shift.”

The team proposed two possible mechanisms for that shift in expectations. The first is that infants with more depressed mothers may receive less sensitive caregiving, so their expectations diminish. The second possible explanation is that the infants with depressed mothers may have a harder time regulating themselves in a novel environment — such as the lab — in ways that interfere with their processing of the videos.

It’s still unclear what the exact mechanism is, but the team said this research opens avenues for future research. For now, the research can help inform parents about how infants may process social interactions they observe in daily life between unfamiliar caregivers and their babies.

The study, “Infants' expectations about caregivers' comforting behavior and associations with maternal depressive symptoms at 6, 9, and 12 months,” is published in Developmental Psychology [DOI: 10.1037/dev0002209]. Authors include Kexin Hu, Seowoo Kim, Kyong-Sun Jin, Renée Baillargeon, and Nancy McElwain.

Research in the College of ACES is made possible in part by Hatch funding from USDA’s National Institute of Food and Agriculture (award no. ILLU-793-339). The study was also supported by the John Templeton Foundation and the National Institute of Mental Health of the National Institutes of Health, under award no. R21MH112578.