A new research shows that shoppers who use phones for tasks unrelated to retail tend to purchase items they didn’t plan to buy or forget ones they did.

For the shopping study, which was published in the Journal of the Academy of Marketing Science, a team of researchers surveyed 2,520 shoppers and observed that those who used their phone for shopping unrelated tasks while in the store bought 9% more unplanned items.

"Our finding that phone use that is unrelated to shopping negatively affects shopping behaviour was in stark contrast to beliefs held by consumers," said study author Michael Sciandra from Fairfield University, US.

The researchers then conducted an experiment in which they asked 231 participants to watch a video recorded from the point of view of a grocery shopper who placed nine items in their cart, but picked up and put down several others.

They found that consumers who are highly dependent upon mobile phones, characterised by excessive use of and reliance on the device, were the most at risk of deviating from a shopping plan while engaging in shopping-unrelated mobile phone use.

"Mobile phones are quickly becoming the principal distractor for many consumers and they offer a unique form of interruption. Our findings may influence consumers' attitudes towards mobile phone use while shopping and persuade them to reflect on how these devices impact our lives, both positively and negatively," Sciandra added.