The Phone Study: The Mere Presence Effect

In a study at the University of Texas at Austin, nearly 800 students took tests that required full concentration. Some kept their phones on the desk, some kept them in a pocket or bag, and some left them in another room. Every phone was silenced, and it made no difference whether it was on or off. The students whose phones were in another room scored the highest. The students with phones on the desk scored the lowest. None of them were looking at their phones.

Part of the brain was assigned to the phone anyway, working to keep from thinking about it, and that effort used up brain capacity the students needed for the test. The brain keeps track of what is near it whether we are aware of it or not. A circuit cannot run at full strength when part of the current is being pulled away.

Researchers call this the mere presence effect. Adrian Ward, who led the study, called it a brain drain. An object can affect the brain just by being nearby, without being used or even noticed. The brain automatically keeps part of its attention on what matters to us, and a phone matters to most people.

This is different from the placebo effect. The placebo effect depends on a conscious belief, such as believing a pill will help. The mere presence effect happens below awareness. The students did not believe anything about their phones, and most did not feel distracted, yet their scores still dropped. What the two have in common is that both show the brain responding to something the person is not consciously controlling, and both have a measurable effect on the body or on performance.