Cash rewards are a common form of (0)MOTIVATION (MOTIVATE) used by parents with high (1) (EXPECT) to encourage their children to work hard at exam time. Some youngsters receive (2) (PAY) of as much as £100 for each A grade they obtain. But should such 'bribes' be based on exam (3) (PERFORM) or should they, as many parents and teachers feel, be offered in (4)