The survey of 1,014 people aged 16 to 23 finds they run an average of 3.6 social media accounts - with women (3.8) slightly higher than men (3.4), and the average nearing four among those aged 16-18.
It also shows nearly half have separate social media accounts that some friends or close family do not know about - a trait more common among men (52 per cent maintain such accounts) than women (40 per cent).
Fifty seven per cent say they share less than they used to as a result of privacy concerns - for those aged 16-18, the figure rises to around 60 per cent, but drops below 50 per cent for the older survey respondents.
The average age at which they got their first smartphone is 12.5 - with two per cent claiming to have been given one before they even turned three. The average age appears to be dropping: the 16-year olds surveyed gave an average age of just above 11, while it reached 14 for those aged 22 and up.
David Wiles, director at Good Relations, commented on the study: "The iGen have grown up with technology and this shapes how they see the world.
"They are not just 'playing with their phones', they’ve integrated technology into their lives... mini marketing directors with a flair for channel-specific communications, this audience group gives any digital marketer a run for their money."
Elsewhere, the survey shows that 64 per cent of the iGen have experienced bullying, trolling, abuse or discrimination on social media. That figure is 62 per cent for women and 67 per cent for men.