The amount of time eight to 15-year-olds spend on the internet has more than doubled over the past decade, Ofcom’s report into media attitudes among children and parents found.
But these so-called digital natives – children who have grown up with the internet – often lack “online nous” to decide if what they see is true or impartial, the regulator concluded.
Almost one in ten children who go online (8 per cent) believe information from social media websites or apps is “all true” – doubling from 4 per cent last year – and most 12 to 15-year-olds are unaware that “vloggers”, or video bloggers, can be paid to endorse products.
Almost a fifth of online 12 to 15-year-olds (19 per cent) believe information returned by a search engine such as Google or Bing must be true, but only a third (31 per cent) are able to identify paid-for adverts.
The study found children are increasingly turning to YouTube for “true and accurate” information about what is going on in the world, with 8 per cent of online youngsters naming the video sharing site as their preferred choice for this type of information - up from 3 per cent last year.
But just half of 12 to 15-year-olds who watch YouTube (52 per cent) are aware that advertising is the main source of funding on the site, and less than half (47 per cent) are aware vloggers are often paid to favourably mention products or services.
Children aged 12 to 15 were split on whether being online helped them be themselves, with 34% agreeing and 35 per cent disagreeing, while 31 per cent were unsure.
The study did find that almost three quarters of older children (72 per cent) believe most people behave differently when they are online, and more than two-thirds (67 per cent) of older girls with a social media account said there were things they disliked about it compared with 52 per cent of boys.
Almost a third (30%) were concerned about people spreading gossip or rumours and a quarter (23 per cent) said people can be “nasty, mean or unkind to others”.
Surprisingly, many children are also concerned about spending too much time online, the survey found.
Around one in 10 online children aged eight to 15 (9 per cent) said they disliked spending too much time on the internet, and almost a third of 12 to 15-year-olds (31 per cent) admitted they could sometimes spend too much time on social media in particular.
Almost all children - 97 per cent - could recall advice they had been given about staying safe online, particularly from parents.
The large majority (84 per cent) said they would tell their parents, another family member or a teacher if they saw something online they found worrying, nasty or offensive, but 6 per cent of children say they would not tell anyone.