Using the internet is physically changing our brains so that we have shorter attention spans and worse memory, major study has suggested.
A review by academics from Oxford, King's College London, Harvard and Western Sydney University, found smartphones were also replacing our ability to remember facts while tricking us into thinking we are smarter than we actually are.
The findings come after a global team reviewed scores of studies and experiments to assess the impact the internet has had on our brains over the last three decades. It comes as earlier this month Ofcom found that the average British adult is now spending 50 whole days a year online.
Dr Joseph Firth, Senior Research Fellow at Western Sydney University said: "The key findings of this report are that high-levels of internet use could indeed impact on many functions of the brain.
"For example, the limitless stream of prompts and notifications from the internet encourages us towards constantly holding a divided attention — which then in turn may decrease our capacity for maintaining concentration on a single task."
Experiments reviewed in the study showed that people who spent their time constantly flipping between short activities online "require greater cognitive effort to maintain concentration". The endless stream of notifications and digital distractions were found to be physically influencing the brain, with those affected showing less grey matter in the cerebral areas that are associated with maintaining focus.
Other studies showed the internet having an immediate impact on our ability to concentrate, with people displaying a reduced capacity to maintain attention after activities such as internet shopping. Whereas offline activities such as reading a magazine showed no such impact.
Multitasking online was even found to make people less effective at multitasking offline. The study said: "Overall, the available evidence strongly indicates that engaging in multi-tasking via digital media does not improve our multi-tasking performance in other settings — and in fact seems to decrease this cognitive capacity through reducing our ability to ignore incoming distractions."
As well as the internet making us more distracted, the study found evidence that it was becoming our "external memory" as we relied more and more on smartphones to retrieve information. However, instead of learning new facts gleaned online, the brain tended to instead log where to find the information on the internet.
One experiment showed that a group of people searching online found information faster than another using encyclopedias, but were less able to recall the information accurately. Other studies showed the internet is deceiving people into thinking they are smarter than they are as they "blurred the lines" between their own memories and what they can easily look up on ever-present smartphones.
The report said: "Results showed that online searching increases our sense of how much we know, even though the illusion of self-knowledge is only perceived for the domains in which the internet can 'fill in the gaps' for us."
The study noted that there could be an upside to this reliance on the internet as a virtual memory in the future, as it could free up brain power for other activities — although it did not speculate what these could be.
The academics found that the social side of our brains acted in a very similar way online as offline. Yet, we are being put under new stresses, such as the stark rejection people feel from having social value quantified by the number of friends and likes they receive, as well as constantly comparing ourselves with "hyper-successful individuals" who are ubiquitous on social media.