Face it, we often make lousy financial decisions.

Among them: Failing to contribute to a 401(k) retirement plan even when your employer matches part of your contributions (free money!) or selling a stock only after it tumbles.

Richard Thaler, a University of Chicago professor, this week was awarded the Nobel Memorial Prize in Economic Sciences for his research into just this, the study of human behavior in decision-making, also known as behavioral economics.

His work established that the “rational man,” a longtime theme in classical economics, isn’t always rational. Because we humans often don’t act in our own best interest, he theorized, we don’t make the best choices when it comes to important decisions about our finances.

But Thaler and his peers also found that our irrational behavior often fits into predictable patterns, which means we can use prompts, or "nudges," to help us make better choices and improve our financial well-being. Thaler and Cass Sunstein, a lawyer, wrote a bestselling book on the subject called "Nudge" (Yale University Press, 2008).

"His impact is enormous, way beyond what an academic can expect to have," says Meir Statman, professor of finance at Santa Clara University and also an expert in behavioral finance. "It's helped many savers prepare better for retirement."

Thaler wasn’t available to comment for this story, but here are four common scenarios from his research, along with advice on how to make yourself a better saver, spender and investor:

We don’t save enough without a nudge. Thaler showed that people are more likely to save if it's automatic, rather than an option. Large employers have used his ideas to add auto-enrollment to their 401(k) plans, signing up new employees for automatic payroll deferrals but giving them the opportunity to opt out. Studies have shown that as a result more people participate in 401(k)s, and typically don't opt out.

What you can do: If you haven’t been auto-enrolled, sign up for automatic 401(k) deferrals, or direct deposit of a portion of your paycheck into an IRA. Experts say a good goal is to eventually save about 10 to 15 percent of your income.

Also, if it’s available, sign up for auto-escalation, which automatically increases your 401(k) contribution each year to ensure you're eventually saving a healthy percentage of your income. It your plan doesn’t offer auto-escalation, put a personal reminder on your calendar to remind you to increase that contribution at the beginning of each year. 

We focus on the short term. Thaler and three colleagues determined that people often measure their monetary gains and losses over short, easy-to-measure periods of time. But investors, for example, would fare better overall if they ignored their holdings' daily fluctuations, which could lead them to sell prematurely. 

What you can do: Stick to low-cost index funds and exchange-traded funds; their performance is less prone to daily swings than individual stocks. And keep your holdings for the long haul. Check your portfolio every month—or less—and ignore daily and weekly ups and downs.

We don't make changes, even if change would benefit us financially. 
Thaler calls that the "status quo bias." Traditional economics says the "rational man" would always gravitate toward the best, least-costly or most profitable options, but Thaler and his peers observed that we're creatures of inertia.

What you can do: If it's been a few years since you've shopped for auto or home insurance, cable or other service providers, look around. For car insurance, you can check prices on a site like TheZebra.com, which lets you compare quotes from many companies. We recommend repeating that process every three years.

More on saving and spending from Consumer Reports

We engage in "mental accounting." Thaler has written that we mentally categorize our money, and that our spending and saving behaviors differ depending on what we are buying. For instance, we might constrain our lunch spending each week but splurge on morning coffee; we treat two expenditures as different "accounts," though they come from the same source. We refrain from buying a bouquet of flowers because we don't have cash on hand, though we could easily use a debit card; we treat the cash in our wallets and cash in the bank as different accounts.

Mental accounting, combined with self control, can help people save, says Santa Clara University's Statman. Once a portion of people's income is diverted into a 401(k), they think about it as capital, not income. Mentally, they treat it differently. So they don't touch it. They let it grow.

But mental accounting can have a negative side. 

"When retirement comes, some people are so wedded to the idea of not dipping into their capital that they live like misers," Statman says. "Self-control can be excessive."

What you can do: Check your bank for free online tools and apps to help you track spending while not shortchanging yourself. And if you're in or nearing retirement, talk to a financial planner about what you can afford to spend each month. A common rule of thumb is 4 percent of your portfolio, but depending on your age, how much you've saved, and some other factors, you may be able to spend more without pain.