Psychologists have discovered that people use their smartphones twice as often as they think, checking them about 85 times per day.

According to researchers from Lancaster University in the UK, ‘rapid mobile phone interactions' are now becoming habitual for smartphone users.

They asked 23 people aged between 18 and 33 to estimate how often they used their mobile phones. An app was also installed in the phones to record actual usage over a two-week period.

Activities included everything from phone calls and texting to checking message notifications, social media alerts and the time.

The researchers found that people tended to use their phones for short bursts of time. Over half of use was less than 30 seconds. However, they also spent far longer on their phones than they estimated.

According to psychologist, Dr David Ellis, the participants were found to use their phones for an average of five hours per day, which is about a third of the time they are awake each day.

Overall, they checked their phones around 85 times per day. However this usage was twice as often as the participants thought.

"Psychologists typically rely on self-report data when quantifying mobile phone usage in studies, but our work suggests that estimated smartphone use should be interpreted with caution," Dr Ellis said.

Details of these findings are published in the journal, PLOS (Public Library of Science) ONE.