In pricing theory, the scarcity principle suggests that the price for a scarce good should rise until an equilibrium is reached between supply and demand. However, this would result in the restricted exclusion of the good only to those who can afford it.
Children aged between three and seven should be limited to half-an-hour to an hour of screen time each day, he said. Those aged seven to 12 should spend just one hour in front of screens. Children aged 12 to 15 should have a maximum of 1.5 hours in front of screens and those aged 16 and over should spend just two hours, he recommends. ''Reducing total daily screen time for children, and delaying the age at which they start, could provide significant advantages for their health and wellbeing,'' he writes.
The Longitudinal Study of Australian Children found that 12-13 years olds were spending up to 30 per cent of their waking day using screens, considerably more than the healthy guidelines. media_cameraNicholas, 13, and Daniel, 9, spend up to five hours a day playing computer games, their mother says.