Text 2 First they went for tobacco,coal and sugar.Now they are targeting smartphones and social media.On January 6th two large investors in Apple demanded that the technology company must help parents curtail their children"s iPhone use,citing research into the links between adolescent social-media habits and risk factors for suicide,such as depression.Old and new media abound with reports about phones"addictive,mind-warping properties.On the school run,parents compare tactics for limiting screen time.Something has made today"s teenagers different from teenagers in the past.As well as being far more temperate and better-behaved,they seem more anxious and unhappy.School surveys by the OECD,a club of mostly rich countries,suggest that 15-year-olds find it harder to make friends.Before stampeding for the off switch,parents and others should ask two questions.First,are iPhones,Instagram and so on actually to blame for adolescents"problems?Second,will curtailing their use do much good?On the available evidence,the answers are,respectively,maybe and no.Some studies of Britain and America,which conduct large surveys of young people,have found correlations between heavy technology use and unhappiness.Correlation is not causation,however:it could be that unhappy people seek refuge online.And the correlations are very weak.Only about l%of the variability in young people"s mental wellbeing can be explained by social-media or smartphone use.One British study suggests that eating breakfast regularly is more than three times as important.Perhaps technology has messed up all young people,even those who stay away from it.Maybe it makes everyone feel left out,or prevcnt all intimate connections:if your friend is ahvays looking at her phone,it may not matter much whether you are.But if the effects are so shapeless it is hard to know what to do.Should parents gang up on teenagers as a group and enforce a universal crackdown?Should they deal with the inevitable charge of unfairness by applying the same restrictions to themselves?Good luck with that.Parents who worry about their teenage offspring can do something,however.Prod them out of the house,and worry a bit less about what they get up to.There is plenty of evidence for the cheering effects of hanging out with friends.Yet youngsters are doing less of this.Over-protective parents are probably one reason.Social pressure is another.It is revealing of broader attitudes that,in Britain,"teenagers hanging out on the streets"is a standard measure of anti-social behaviour.The authoritative Crime Survey of England and Wales asks people whether it is a problem where they live,alongside things such as drug dealing and burnt-out cars.That the rate of adolescent hanging-out has dropped from 33%t0 16%in ten years may please criminologists,but is unlikely to signal happier teenagers.30.The decreased rate of hanging-out