The Nobel Prize in Economic Sciences for 2017 was awarded to **Richard H. Thaler**, an American economist known for his work in behavioral economics.

Thaler's research focuses on how people make economic decisions that are not always rational. Traditional economics assumes that individuals always make logical choices to maximize their benefits. However, Thaler showed that real-life decisions are often influenced by psychological factors like emotions, habits, and social norms.

One of his key contributions is the concept of "mental accounting," where people treat money differently depending on its source or intended use. For example, someone might splurge a tax refund on a luxury item but hesitate to spend their regular income the same way.

Thaler also introduced the idea of "nudging," which involves subtly guiding people towards better decisions without restricting their freedom of choice. This concept has been applied in various public policies, such as encouraging people to save more for retirement by automatically enrolling them in savings plans.

His work has had a significant impact on both economics and public policy, making economic models more realistic by incorporating human behavior. By acknowledging that people often act irrationally, Thaler's insights help design better economic policies that align with actual human behavior.

So, the correct answer is **Richard H. Thaler**.