boredom and frustration
Of course, not all work is enjoyable. It could be that your child decides on a course of study, as preparation for a future career, and quickly becomes bored or frustrated. But if the motivation has come from within, there should be a goal to aim for; unless there are serious problems, he will probably work through the boredom for the sake of the eventual goal. This can be good preparation for adult life, when they may frequently need to do chores or work which are not innately appealing – such as laundry – in order to gain something for which they are motived, such as clean clothes!
When the child has spent the pre-teen years discovering the joy of learning, free to ask questions and follow his own interests entirely, it is a natural step to realising that some interests require depth of study which may be tedious, or difficult. Parents should never push their children into study, although reminders may be useful and assistance in making plans for assignments or revision for courses with a time-limit.
External motivation – on occasion
Obviously there are times in adult life when we work for external motivation – such as a paycheque! There’s no reason why our teenage children shouldn’t, at times, agree to particular jobs such as babysitting or mowing the lawn, for which we pay them. They should expect to take a normal part of family life and chores, appropriate to age. But if there are jobs which we might pay someone else to do, you could offer them to your children instead, if they are capable and willing.
If they can find something to do which they also enjoy, so much the better. This is good experience preparing them for the world of work. There is no hard-and-fast rule, however. As our children grow up they will inevitably find times when motivation is at least partly from outside. But I would encourage everyone to take every opportunity to encourage their children’s internal motivation. Then you can help them to see education and learning as an exciting, life-long adventure.