Rewards: Carys Grinnell's parents will buy her a car if she does well at uni. Photo: James Brickwood
Sydney parents are paying for their teenage daughters to have cosmetic injections as a reward for graduating or performing well at high school.
Students have also received offers of cars, new iPhones, money for overseas trips and One Direction merchandise.
Lips and cheek augmentation are very, very common.
But, although there is some evidence to suggest such incentives can yield results, experts said there are also risks.
Cosmetic nurse Matty Samaei: Said it is ''extremely common'' for high school girls to have their lips plumped up as a reward for graduating.
Cosmetic nurse Matty Samaei is the owner of The Medispa at Neutral Bay, where she said it is ''extremely common'' for high school girls to have their lips plumped up as a reward for graduating.
''Lips and cheek augmentation are very, very common with the girls prior to the formal and graduation,'' she said.
The procedure used to enlarge lips costs between $350 and $750 and ''the parents always pay for it'', she said.
''Most of the mothers have had cosmetic surgery themselves.''
She said that the high school formal weeks were the clinic's busiest all year, estimating that during that period last year they injected about 100 high school girls.
One of her clients is 17-year-old Sarah, who asked that her surname be withheld. She recently had her lips enlarged before her high school formal later in the year and said receiving rewards for graduating was very common among her friends at the lower north shore private school she attends.
''I have friends who have nose jobs and stuff booked for the end of the year as presents,'' she said. ''[And] there's obviously the normal [rewards], like trips overseas and cars and stuff but this is the one I wanted.''
Carys Grinnell's parents have promised her cash to buy the ''little and cute'' car she wants if she performs well at university.
The 17-year-old's family, from Edgecliff, created a contract, via one of several websites, that put in writing rewards they were willing to give for specific educational goals.
If she achieves a subject credit, for example, they will take her for a driving lesson. For a distinction, they will pay for a professional instructor. And, at the end of the semester, if her grades are up to scratch, they will put money towards a car.
''If you want to do well it's good, but I'm someone who won't stay motivated for that long,'' she said.
''I have little bursts of, 'I'm going to be fabulous,' then two weeks later I'm like, 'I'd rather watch Bold and the Beautiful than read Charles Dickens, thanks.'''
Carys' mother Rachel Ellsworth hopes the incentive program will motivate Carys throughout her university degree. ''I think that if she experiences success in the first year it will encourage her to keep doing her best thereafter,'' she said. ''It may get expensive but I'm definitely happy to discuss it further with Carys.''
Yasmin El-Ghoul is in year 12 at Amity College, and was promised an iPhone 5 from her parents if she scored over 90 in her extension 1 HSC mathematics course last year.
One of her friends was promised a new piece of merchandise for the boy band One Direction for each assessment in which she scored over 90. ''I didn't expect them to follow through but they did,'' the 17-year-old said. ''I like to do the best that I possibly can but it just pushed me that little bit further.''
One website, 3 Fat Carrots, formalises incentives between students and their family and friends, ensuring students are not let down by parents who fail to follow through on agreed rewards. The site's marketing director, Silvana Carvell, calls incentives ''study carrots'' and said they can be either material or priceless, which may be ''your mum agreeing to cook whatever you want once a week''.
University of Sydney economics professor Robert Slonim said the research is still out on how successful incentives can be in education.
''They may work if they can indicate what students should focus on or if students care dramatically about the near-term benefits relative to distant and harder-to-imagine future,'' he said.
But it can backfire: ''If you start giving out rewards, there's a concern this may undermine those intrinsic motivations for why you should care about education in the first place.''
Educational psychologist Juliet Moore said offering material incentives is the wrong approach, especially for older students.
''It would work for those who are probably good at cramming,'' she said. ''Both parents and teachers have a responsibility to help students find internal motivation and a love of learning. And you're setting that person up to be demotivated in the workforce.''