India, Aug. 16 -- Tangible rewards motivate employees when they're easy to use, pleasurable, unexpected, and distinct from salary, a new study found.A recent survey of firms in the United States revealed that 84 per cent spent more than $90 billion annually on tangible employee rewards, such as gift cards, recreation trips and merchandise in hopes of increasing productivity."We found that there is, at best, mixed evidence regarding the motivational efficacy of tangible rewards versus cash rewards," said Adam Presslee, an associate professor at the University of Waterloo's School of Accounting and Finance. "It is somewhat puzzling why so many companies go to the trouble of tangible rewards when cash rewards also lead to motivational differ...