The science behind the possible effects that staring at your phone can have on a child.

The still-face experiment, conducted by psychologist Edward Tronick in the 1970s, is often touted as a proposed example of how smartphone use around your baby can be damaging.

During the experiment, videos were taken of mothers and their babies interacting. After two minutes, the mothers were instructed to stop paying attention to their children and to stare at them with a blank, neutral expression not responding to the child at all.

The babies became visibly distressed. They would cry and try to get their mothers’ attention by reaching out and touching them or shaking their heads. Some of them gave up and began to develop self-soothing attempts like sucking the back of their hand or thumbs. Some even began to lose posture control and collapsed in the car seat.

“Someone playing with a modern smartphone is exactly like a still-faced paradigm,” says Caspar Addyman, Ph.D., developmental psychologist, and director of the Goldsmiths InfantLab at Goldsmiths University of London in the United Kingdom. He noted that on YouTube, people have shared videos of their own still-face paradigm experiments with a smartphone instead of a blank stare.

The main reason the smartphone use mimics the still-faced experiment is eye contact, which is a crucial part of normal parent-child interactions and development.

This experiment has been cited as evidence that even two minutes of a parent not paying attention to their baby is damaging, and it’s a good reason to rethink smartphone use around your baby. If you’re looking at your phone, you’re not looking at your child, and that can have consequences.

There have also been several studies showing the importance of regular eye contact in a young child’s cognitive and emotional development.

One study, published in Developmental Science, found that visual communication cues facilitate interpersonal communication. “It is important that we look at faces to retrieve and subsequently process such cues.” -Face-to-face interference in typical and atypical development-Deborah M Riby, Gwyneth Doherty-Sneddon, and Lisa Whittle- 2012

While there is some debate as to whether the still-face experiment really proves that staring at your phone for just two minutes can be harmful to babies, many experts agree that regular smartphone use, in general, can have negative effects on children.

So if you’re a new parent, it might be time to evaluate your smartphone use when you’re around your baby. Even small periods of disconnection from the device can have an impact on your child — and that includes looking at it when they’re trying to interact with you.