Readers using electronic books like the Amazon Kindle and Sony Reader are less likely to remember what they have read because the devices are so easy on the eyes, says a new research from the US.
It has long been assumed that displaying information more clearly and legibly will help readers take it on board, but the truth could be the opposite - that making something easy to read causes the brain to be lazy.
Rather than making things clearer, e-readers and computers prevent us from absorbing information because their crisp screens and fonts tell our subconscious that the words they convey are not important, it is claimed.
In contrast, handwriting and fonts are more challenging to read signal to the brain that the content of the message is important and worth remembering, according to experts.
Researchers asked 28 participants aged 18 to 40 to learn a set of facts about three fictional species of alien, which were written in different fonts.
Those who read the facts in the easy-to-read Arial pure black font retained 14 per cent less information than those who were given text written in the less clear Comic Sans MS and Bodoni MT.
The scientists wrote "making material harder to learn can improve long-term learning and retention. More cognitive engagement leads to deeper processing", enabling the reader to recall the information more accurately.
The study, funded by Princeton University, has been published in the Cognition journal.