A new study published in the journal PLOS One provides preliminary evidence that smartphones are linked to reduced cognitive abilities. The researchers found intensive smartphone use was associated with reduced math performance in particular.

“I got interested in smartphone behaviors because I noticed that many people, including myself, experienced a change in their personal interactions and social behaviours after purchasing smartphones,” said Aviad Hadar of Ben-Gurion University, the study’s corresponding author.

“It is also no secret that smartphones have a powerful capacity to capture our attention and are associated with a wide range and psychological and physiological phenomenon. When I first searched the literature back in 2013, I could not find any studies pointing on a causal link between smartphone usage and cognitive or behavioural changes so I thought it would be interesting to try and bridge this gap.”

The researchers compared 16 heavy smartphone users and 35 nonusers. They found that the heavy users tended to be less accurate when solving simple arithmetic problems. The heavy users also tended to be more impulsive and have increased social concern compared to nonusers.

The two groups also showed some differences in brain activity. The researchers found that heavy smartphone users had reduced excitability in the prefrontal cortex.

In a follow-up experiment, the researchers provided 12 of the nonusers with smartphones for three months while another 16 nonusers continued to not use such a device. The participants who were provided with phones showed a significant reduction in arithmetic accuracy.

Hadar told PsyPost the findings suggest that “intensive smartphone usage can result in changes to our cognitive capabilities, bearing in mind that some of these changes may be disadvantageous and some beneficial.”

“Another important take home message from the study is that intensive usage may cause rise in social concerns,” he added.

But the research has some limitations.

“There are several important caveats to the study,” Hadar said. “First, the sample size in the second experimental phase is small and the effect sizes are small to moderate. This limitation stems from the difficulty in recruiting non-smartphone users who were willing to undergo transcranial magnetic stimulation treatment and a longitudinal intervention. This type of control design in adults is currently implausible due to the difficulty in recruitment.”

“Nonetheless, to better encapsulate the behavioral effects of short exposure larger sample size studies are still necessary. Second, the study lacks conclusive evidence regarding the neurobiological changes accounting for the behavioral effects observed. Finally, we could not track actual usage patterns of ‘old’ mobile phones in nonusers (we followed actual usage used an app only in smartphones).”

“Hence we cannot rule out the possibility that some were in fact heavy users of ‘old’ phones,” Hadar explained. “However, we feel confident to assume that on average the usage of such phones was within normal limits and smaller than that of smartphone users.”

The study, “Answering the missed call: Initial exploration of cognitive and electrophysiological changes associated with smartphone use and abuse“, was also co-authored by Itay Hadas, Avi Lazarovits, Uri Alyagon, Daniel Eliraz, and Abraham Zangen.