There's no shortage of voices warning that our kids' obsession with screens is doing them harm, but first among them is probably Jean Twenge, a psychology professor who has emerged as the country's top prophet of doom about kids and screens (you may have read her memorably titled Atlantic article "Have Smartphones Ruined a Generation?")

Twenge has made a career out of sounding the alarm that too much screen time is behind rising rates of depression and anxiety in young people. Now she and colleagues are out with a new and bigger study in this same genre. The massive trawl through government surveys on the habits and well-being of 1.1 million kids is strong evidence that screen time and unhappiness are rising in lockstep.

If it walks like a duck and quacks like a duck...

The discussion around kids and screens is a tricky one for psychologists as it is both unethical and impractical to design an experiment where you randomly assign half the kids to gorge themselves in mindless YouTube videos and ban the other half from touching a screen to see which group ends up happier.

Instead, scientists have had to rely on studies like Twenge's that look at both screen time and mental health measures and see when the two appear to be rising (or falling) in sync. This sort of research can't definitively prove causation -- some other third factor might be causing both screen time and unhappiness to go up -- but it can nail down how closely linked the two are, providing evidence that one really is driving the other.

And as far as this type of study goes, this one is hard to beat in terms of scale. It found that from the 1960s to the early 2000s kids reported gradually rising levels of life satisfaction, self-esteem, and happiness. Then in 2012 - precisely the time that more than half of Americans started to own a smartphone -- those trends reversed and kid's overall well-being started to decline.

A deeper dive in the data also revealed an association between small doses of screen time and greater happiness on an individual level, i.e. particular kids who reported spending less time with their screens also reported greater life satisfaction. Is that definitive proof that phones are making kids unhappy? No, but it sure looks suspicious.

Skeptics are still not buying it. 

These won't come as any great shock to some, including ironically a lot of tech icons like Steve Jobs and Bill Gates who strictly limited their own kids' screen time. But others remain suspicious of Twenge's quest to convince us all that screen time is making our kids miserable.

Besides underlining that her work can only prove correlation and not causation and that the effects detected are small (kids are only a little worse off), many of these skeptics also take issue with the whole idea of "screen time" as a concept. Screens, they point out, can be used for a whole lot of different activities, from arranging real world activities to watching people blow the heads off digital zombies. It's silly to lump everything together.

"A wave of new research is now challenging the long-held orthodoxy that screen-time is bad for children: some, it suggests, might even benefit them," reports the UK Telegraph. "Consuming digital media does not always lead to children consigning themselves to their bedrooms with just their screens for company. In fact, they can often help to bring families together, as parents watch films, play video games and use messaging apps with their children."

This back-and-forth among experts is confusing for parents, and the bad news is that as the science of kids and screen time is still young, there's unlikely to be a definitive answer any time soon.

Which is also the good news. Given the uncertainty among child development professionals, there is no reason for parents not to trust their own instincts and make decisions about gadgets that seem reasonable to them. The state of the science as of today suggests you should be cautious, be thoughtful, but don't be extreme (or judgmental of other parents' choices.)