Humans are not the only ones who can get pulled into spending a lot of time staring at a screen. In a recent study, common marmosets, small South American monkeys, learned to tap videos on a computerized tablet, just to make the image bigger and hear chattering sounds. There was no food, no treats, nothing you would normally think of as a reward. Just the screen itself was enough to keep them doing it over and over again. If that sounds familiar, it should. The same kind of thing happens when people keep scrolling through social media or checking their cell phone long after they meant to stop. Looking at how another primate gets hooked on a screen can help us understand what is going on with our own screen habits.
In a study by Ando and colleagues (2025), researchers put a tablet in each marmoset’s cage with nine small, silent videos of other primates. When a marmoset tapped one of the videos, that video zoomed in and chattering sounds played. That was all it took. Within a few weeks, most of the marmosets were tapping regularly. Even when the reward was taken away, some of them kept tapping anyway. This suggests that the interaction itself and the change on the screen were enough to keep them going. That is exactly the kind of thing we see in human screen habits, too. People get drawn in by notifications, endless scrolling, and the way the screen changes, even if they are not getting anything all that useful from it.
People talk a lot about how much time others spend on their phones. Years ago, it was mostly a complaint about kids and teenagers. Now you hear it about people of all ages. Psychologists have been trying for years to figure out why we do this. The fact that we have a phrase like “screen time addiction” tells you how common it has become. The mystery is why it happens. Many people will tell you that spending hours on their phone does not really make their life better. They might watch videos for hours, but when you ask them what they got out of it, they will say “nothing.” There is a big gap between how much time people spend on their phone and how much they actually gain from it.
A lot of what comes through a phone is quick posts and short clips, not much that has lasting value. Even the news people get from their phones is often thin. They might spend an hour scrolling through headlines and opinions, but the amount of actual information they get is much less than they could get from sitting down for a half-hour of local or national news. So what is it that keeps us glued to our screens if we are not getting much out of them?
In many ways, it works like an addiction. Addiction usually means doing something because it feels good or rewarding in the moment, even if it does not give you much real benefit. With smartphones, people can spend hours on them and end up with nothing to show for it. Sometimes it even makes life worse because time on the phone takes the place of time with people who are right there in front of us. Anyone who has walked into a restaurant has seen it: two people sitting across from each other, both staring at their phones. In that moment, whatever is on the screen seems more important than talking to the person across the table.
That is why this marmoset study matters. It shows that the draw may not be the content itself, but the act of using the device and the constant change in what is on the screen.
Once you see that, it makes sense why simply changing what you look at on your phone often does not solve the problem. People delete one app only to replace it with another that works the same way. The content changes, but the habit stays. If the reinforcement comes from the way the screen keeps changing, then the first step might be to notice that and tell yourself, “I am not actually getting anything here. I am just reacting to the fact that something is happening on the screen.” That awareness alone can start to break the cycle.
That marmoset study is a good reminder that the pull of a screen is not something unique to humans. Our brains, like nonhuman animals, can get caught up in the simple act of engaging with something that changes in front of us. Understanding that can help us see why it is so easy to lose track of time online, and maybe start figuring out how to take some of that time back.
Next time you catch yourself deep in a scroll, stop for a second and ask, “Am I actually getting anything from this, or am I just hooked on the fact that the screen keeps changing?” If the answer is the second one, put the phone down and look around. There is probably something in the real world worth paying attention to, and it will not disappear if you blink.
