It seems our entire lives are contained in that tiny instrument. In fact, according to data Apple collects, the typical owner uses their phone 80 times per day. Our phones are our constant companions.

Nicholas Carr recently wrote in the Wall Street Journal how our brains become dependent on phone technology and may weaken our intellect.

He writes, in a 2015 Gallup survey that more than half of iPhone users said they couldn’t imagine life without the device, and for good reason. With so many useful functions it’s really a computer that fits in our palm.

But while our phones offer convenience and entertainment, they also breed anxiety. “Their extraordinary usefulness gives them an unprecedented hold on our attention and vast influence over our thinking and behavior,” writes Carr. What happens to our mind when a single tool has such dominion over us?

Scientists are exploring this question. Not only does phone usage shape our thoughts as we swipe our screens, but the effects linger even when we are not using our devices. As the brain becomes dependent on the technology, the intellect weakens.

Carr sites multiple studies showing that when our phone beeps, buzzes, or rings (do they ring anymore?) our attention to the job at hand wanders, we become distracted and work becomes sloppier whether we check the phone or not. In one study, it showed that when the phone beckons but we can’t answer it, our blood pressure rises, the pulse quickens, and problem-solving skills decline.

Dr. Adrian Ward, a cognitive psychologist and marketing professor at the University of Texas at Austin, conducted research showing that as the phone’s proximity increased, brainpower decreased. The more heavily students relied on their phones in everyday life, the greater cognitive decline they suffered. Studies upon studies are showing similar results. The evidence that our phones can get inside our heads so forcefully is unsettling.

The qualities we find most appealing about our smartphones – constant internet connectivity, multitude of apps, responsiveness, portability – are the very ones that provide such influence over our minds.

A seminal study in 2011 led by Columbia University psychologist Betsy Sparrow concluded that smartphone users suffer from the “Google effect.” “Because search engines are continually available to us, we may often be in a state of not feeling we need to encode the information internally. When we need it, we will look it up.” Even Albert Einstein many years ago stated “Never memorize something that you can look up.”

An even more sinister twist is that study subjects were not very good at distinguishing the knowledge we keep in our heads from the information we find on our phones or computers. Dr. Ward explained in a 2013 Scientific American article that when people call up information through their devices, they often suffer from delusions of intelligence. They feel as though “their own mental capacities” had generated the information, not the devices. That insight sheds great light on our society’s current gullibility crisis, in which people are all too quick to credit lies and half-truths spread through social media by various bad actors. “If your phone has sapped your powers of discernment, you’ll believe anything it tells you,” writes Carr.

A good read on some of the psychology behind our cognitive behavior is Mistakes Were Made (But Not by Me): Why We Justify Foolish Beliefs, Bad Decisions and Hurtful Acts by Carol Tavris. I found this book very interesting and insightful.

Perhaps the most important thing we can do for now is to be mindful of ourselves, and perhaps put some distance between ourselves and our phones.