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Brain and Mental Performance Lifestyle

Just Having Your Smartphone Within Reach Diminishes Brain Power

1 year, 10 months ago

12127  0
Posted on Jun 28, 2017, 9 a.m.

Study finds that even if your smartphone is turned off,  your cognitive capacity is significantly decreased just by having it nearby.

A new study conducted at the University of Texas at Austin McCombs School of Business has determined one's cognitive capacity is drastically diminished when his smartphone is in reach. It does not matter if the phone is in the on or off position. Cognitive capacity declines if the phone is at arm's length even if the device doesn't function.

About the Study

Adrian Ward, an Assistant Professor at McCombs, conducted experiments on about 800 smartphone users with the assistance of co-authors. They attempted to measure how well individuals complete tasks when their smartphones were within reach, even if the participants were not using the smartphones. One of the experiments involved the participants sitting at a computer and taking an array of tests that necessitate full concentration for a high score. The tests were then shaped to measure users' available cognitive capacity. This is a reference to the brain's ability to store and process data. The study participants were randomly told to put their smartphones face down on the desk, in their bag or pocket or in a completely separate room before the tests commenced. Each participant was instructed to put their smartphone in silent mode.


The research team determined participants who put their smartphones in a separate room outperformed those who put their smartphones face down on the desk by a significant margin. They also outperformed those who put their phones in their bag or their pocket. The findings show that the presence of an individual's smartphone decreases his available cognitive capacity. The phone's presence even impairs his cognitive functioning.

It is important to note that study participants felt as though they provided their full attention and focus on the matter at hand. The bottom line is that the more noticeable the smartphone is, the more cognitive capacity decreases. Though one's conscious mind is not consumed by the smartphone, the process of requiring oneself to not think about the phone ties up some of the inherently limited cognitive resources. This is commonly referred to as the “brain drain”.

Additional Study

The research team also performed another experiment in which they examined how an individual's self-reported dependence on his smartphone or how strongly he feels he needs the smartphone to get through the day affects cognitive capacity. Participants engaged in the same series of computer-based activities. They were randomly assigned to keep their smartphones face up and clearly visible on the desk, in a bag or pocket or in a separate room. Some of the participants were directed to turn off their smartphones. 

The research team determined those who were highly dependent on their smartphones performed much worse compared to those who were less dependent on their smartphones. However, this only proved true when the smartphones were kept in their bag or pocket. It was determined that it did not matter if a participant's smartphone was on or off or whether positioned face up or face down on the desk. Merely having a smartphone within one's line of vision or within one's reach decreases his ability to maintain a focus and complete tasks. This is due to the fact that a part of the brain is actively working on not grabbing or using the smartphone.


It is not the distraction caused by smartphone notifications or other smartphone-related stimuli that impact cognitive ability and capacity. It is the presence of the device that diminishes cognitive performance. This is bad news for smartphone owners. It might even inspire some to revert back to those flat “dumb phones” that allow for calls and texts but lack web access.

Adrian F. Ward et al. Brain Drain: The Mere Presence of One's Own Smartphone Reduces Available Cognitive Capacity, Journal of the Association for Consumer Research (2017). DOI: 10.1086/691462

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