A constant stream of electronic 'junk' is damaging people's ability to think compassionately, scientists say.
The deluge of information from 24-hour news, mobile phones, emails and social networking sites such as Twitter moves too fast for the brain's 'moral compass' to process, two studies suggest.
Twitter, where people post short updates about their lives for friends to view, has soared in popularity thanks to celebrity users such as Stephen Fry and Jonathan Ross. It has about 10million patrons worldwide.
If brains become numbed by the stream of digital information, then people could lose the ability to feel altruism or sympathy for others, researchers claim.
The new fears are raised by two American studies into the way the brain reacts to information and emotion.
Earlier this year, Baroness Susan Greenfield, the director of the Royal Institution, came under fire for suggesting that social networking sites could be harmful.
Felix Economakis, a London chartered psychologist and stress expert, said: 'Our poor brains are definitely suffering information overload.
'Technology is making quantum leaps, bombarding us with new things to focus on, but we have not been able to catch up and adapt.
'Our brains' attention levels are finite. When everything is screaming at us, we start withdrawing so that normally nice people become unempathetic.'
The two studies suggest information overload can trigger the brain's 'fight or flight' response - and sideline more compassionate, thoughtful responses to news and information.
One of the new studies suggests rapid fire news updates and instant social interaction are too fast for the 'moral compass' of the brain to process.
It also suggests that heavy Twitter and Facebook users could become 'indifferent to human suffering' because they never get time to reflect and fully experience emotions about other people's feelings.
Dr Mary Helen Immordino-Yang, who led the research at the Brain and Creativity Institute at the University of Southern California (USC), said: 'For some kinds of thought, especially moral decision-making about other people's social and psychological situations, we need to allow for adequate time and reflection.
'If things are happening too fast, you may not ever fully experience emotions about other people's psychological states and that would have implications for your morality.'
Her study used brain scans to monitor the responses of 13 volunteers to compelling, real-life stories.
The stories were designed to provoke admiration for virtue or skill, or compassion for physical pain.
The brains of the volunteers responded in fractions of seconds to signs of physical pain in other people - but needed six to eight seconds to fully respond to stories of virtue or social pain.
However, the responses lasted far longer than the volunteers' reactions to stories focused on physical pain.
The findings suggest that if people are constantly bombarded with new information, they may not have long enough to absorb it and come up with a suitable, compassionate response.
The second study at the University of California, San Diego, showed that universal traits of human wisdom - such as compassion, empathy and altruism - are hard-wired into brains.
The brain cells dealing with those emotions are found in the pre-frontal cortex - the slower acting part of the brain that is sidelined when the world is stressful.
Prof Dilip Jeste, who led the study, said positive behaviours such as admiration and indignation are more work for the brain than negative , basic ones such as the pain response.
'Constant bombardment by outside high-intensity stimuli is not likely to be healthy,' he said.
But supporters of new technology argue that social networking sites expands people's friendships and offers them new ways to stay in touch - and that studies of brain cells cannot show that Twitter and Facebook are harmful.
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