The use of digital technologies is reshaping human brains and the impact on young people must be considered by their parents and educators, a neuroscientist warns.

Susan Greenfield of Oxford University said technology was re-wiring brains, particularly for young people who were growing up knowing nothing else.

Baroness Greenfield gave a sold-out public lecture at the University of South Australia on Wednesday night, having previously worked in Adelaide as one of the South Australian Government's thinkers-in-residence.

"People like me, a baby-boomer, grew up with the television being the new luxury that came into our home," she told 891 ABC Adelaide.

"Clearly the amount of life we've lived already, the experiences we've had, the conceptual frameworks that we've developed, the attitudes we have, the memories that we have - the individuality that we've therefore developed - all those things will offset against whatever other influences are coming in."

The same could not be said of the younger generation, she argued.

"If you're a very young person and you haven't developed, let's say, a robust sense of identity, you haven't got interpersonal skills, then clearly we're going to see changes that we might not see in someone who's older," she said.

The neuroscientist warned children who once used their imaginations were now more likely to sit in front of a screen, with a menu of choices someone else had designed.

"The issue is that information isn't knowledge. Of course you can be bombarded with endless information, endless facts, but if you can't make sense of them one fact is the same as any other fact," she said.

"You can cruise on YouTube or on Google going 'yuck' and 'wow', but you're not actually making sense of things."

Impressing your social media 'audience'

She said an inspirational teacher or parent could be the key to young people developing the skills "to join up the dots" of the world around them.

Baroness Greenfield said social media had its worthwhile uses, such as for communicating with family or friends across the world, but there was a problem when people had lists of friends "they didn't actually know".

She said such "friends" were actually more of an audience.

"You are out to entertain and seek their approval and the danger lies then in constructing an artificial identity that's not really you at all," she said.

"Everything you do is done for the approval and to impress this audience, who inevitably will be vicious and nasty because they're not constrained by face-to-face communication."

She feared some young people might grow up with short attention spans, keen to conform with their peers and lacking an ability to discern impact of their actions.

"I just wonder whether we might be looking at a generation who are completely self-centred, short attention spans, not very good at communication, rather needy emotionally and with a weak sense of identity?" she said.

"[We need to] look at how we deal with that situation rather than just saying it's all cool, 'we've all got iPads and aren't we trendy?'"

Pace of technological change 'unprecedented'

Baroness Greenfield said the pace of change was exceeding the technological advances of the past.

"People have often said to me 'What about the car and the television and the refrigerator and the printing press even?' They did make greater advances with those technologies on some people's lives, but we were still living in the real world when we use those things," she said.

"Nowadays you could wake up in the morning and you could work, you could play games, you could shop, you could go dating all without actually living in three dimensions.

"It has become pervasive and I suggest this is a parallel universe that might tempt some people away from the real world to exist in this sort of cyber-reality of hearing and vision."

Susan Greenfield feared virtual worlds might rob the young of genuine imagination. ( ABC )

She said some people might live in front of screens in a "world where you don't look someone in the eye any more, you don't hug them".

"My concern is that, for some, it has become an end in itself whereas in the past the technologies have been a means to an end."

Baroness Greenfield said digital technologies had brought some amazing advances, such as finding information in just a few keystrokes, but she sounded a note of caution.

"As a neuroscientist I am very aware that the brain adapts to its environment - if you're placed in an environment that encourages, say, a short attention span, which doesn't encourage empathy or interpersonal communication, which is partially addictive or compulsive ... all these things will inevitably shape who you are," she said.

"The digital world is an unprecedented one and it could be leaving an unprecedented mark on the brain."

She said her aim was to encourage wide discussion about where societies were headed.

"What we need to decide - and there's not an easy answer, there never is - is what kind of society we want, what kind of world do we want to live in?" she said.

"We in the developed world have the most amazing opportunities to develop ourselves as individuals in ways that no-one else has been able to do before."

She said children born now with the possibility of living perhaps to 100 would have to decide "what to do with the second 50 years of their life".

"It's a question people often don't think about - they know what they don't want but it's very hard [when people are] given a choice. Choice is not the luxury it might seem," she said.