Glancing at your phone can begin to compromise your cognitive skills once it passes a certain threshold. Studies from Nottingham Trent University in the UK and Keimyung University in South Korea found that checking your phone about 110 times a day may signal high risk or problematic use.
Over eight years of research involving teenagers and millennials, Larry Rosen, a professor emeritus of psychology at California State University, Dominguez Hills, observed that participants checked or unlocked their smartphones between 50 and more than 100 times per day, on average every 10 to 20 minutes while awake. Both Android and iOS devices allow users to check the number of unlocks – called pickups – in their settings.
“The phones and digital media are reinforcing for our brains, activating the same reward pathway as drugs and alcohol. The phones create a compulsive habit loop where we check without thinking and experience withdrawal when we don’t check or don’t have access to our phone,” said Anna Lembke, a professor of psychiatry and addiction medicine at Stanford University School of Medicine.
According to a survey conducted by YouGov in May on phone use, when Americans were asked where they place their devices before going to sleep, eight out of 10 said they keep them in their bedrooms, most often next to their beds.
People underestimate how often they check their phones. When asked in the same survey how many times they pick up their devices each day, most respondents believed they did so about 10 times.
Broken focus
A study by the Singapore Management University found that frequent interruptions to check our devices lead to more attention and memory lapses. Unlike total screen time, the frequency of smartphone checks is a much stronger predictor of daily cognitive failures.
Constantly unlocking the phone forces the brain to switch rapidly between tasks, eroding the ability to focus on just one. Decades ago, influential computer scientist Gerald M. Weinberg warned that working on multiple tasks and frequent task-switching could cut productivity by up to 80%.
The habit is widespread. YouGov found that more than half of Americans check their phones multiple times during social activities such as eating with others or meeting friends.
At work, during a 30-minute meeting, one in four people admitted to checking their phone at least once. After each workplace interruption, it can take more than 25 minutes to regain focus, said Gloria Mark, a researcher at the University of California at Irvine.
Most people receive push notifications throughout the day, such as messages, emails and alerts, many of which originate from social media platforms. “Our constant need for connection increases the brain’s biochemistry, particularly anxiety-producing chemicals such as cortisol, which nags at us to ‘check in’ upward of 100 times a day,” Rosen explained.
Beyond just young people
Life has changed since modern smartphones entered our lives in 2007 with the launch of Apple’s iPhone. Today, most US adults own one of these devices, and nine out of 10 use the internet daily, according to a recent Pew study.
The habit of picking up the phone extends across generations. “Whatever generational differences that were studied when the smartphone and social media arrived are now basically minimal. We are all beholden to our smartphone-delivered connections,” Rosen said.
German researchers from Heidelberg University found that after just 72 hours without smartphone use, brain activity began to mirror patterns typically seen in substance withdrawal. The investigation suggests that short breaks from smartphone use can help reduce problematic habits by reorganising our reward circuits, making them more flexible.
Experts offered simple ways to break unhelpful device habits. “Make the phone less reinforcing by turning off notifications, deleting all but the most necessary apps, going grayscale and powering the phone off between use. I also recommend leaving the phone behind on occasion, just to remind ourselves we can still navigate the world without our phones,” Lembke said.
“Take back control over how often we check in and set tech breaks which we control, not our phone,” Rosen said.
About this story
Amy is a composite character who illustrates usual patterns of phone usage. Her example in this story is based on aggregated daily data collected from a dozen high-frequency, US-based users who shared their hourly phone pickup patterns on a weekday. For each device, the proportion of phone checks per hour was calculated relative to the total number of checks recorded in a day, which ranged from 100 to 225. This calculation was then used to determine the average values presented in the example. The distribution of phone checks within a one-hour period, presented at the beginning of this story, is intended as an example representing a time of high checking frequency. The 5pm to 6pm interval was selected because it corresponds, on average, to the hour with the highest number of checks among the participants.
The YouGov phone use survey was conducted May 23-26 among 1129 respondents selected from YouGov’s opt-in panel to be representative of US adults.
High-risk checking level is referenced according to the studies “Passive Objective Measures in the Assessment of Problematic Smartphone Use: A Systematic Review” (Department of Psychology at Nottingham Trent University, 2020) and “Analysis of Behavioural Characteristics of Smartphone Addiction Using Data Mining” (TabulaRasa College at Keimyung University, 2018).