Willpower can be drained. And that's where unconscious motivation comes in, according to a new study.

Researchers from the Technische Universität München in Germany found that because willpower can only take us so far in completing a taxing task, we also use unconscious motivation to get things done.

The study, published in the Journal of Personality, had several parts. For one experiment, researchers gauged study participants' motivation for control and influence. Then, they had them watch a scene from the Dead Poets Society movie, where a dad forbids his son from becoming an actor. Afterward, the participants were assigned to play the role of the father in a reenactment of the scene, or to just write down dialogue from it.

Next, researchers had participants watch a funny scene from the Ice Age movie, but they were instructed not to laugh or smile in response to it.

People who had more motivation for control and influence were more easily able to stifle their laughter or smiles during the Ice Age scene. Researchers said that this is likely because they were able to draw from their own motivations for control and influence to do the first task -- to play the part of the controlling father -- which then left them with the remaining willpower to be able to successfully stifle the laughter in the second task.

However, past research suggests willpower may not be a finite resource for all people. LiveScience reported on a study, published earlier this year in the journal Proceedings of the National Academy of Sciences, that showed that people's beliefs about willpower -- if you believe it can be quickly depleted, or if you believe you have unlimited amounts of it -- influence their ability to perform.

Want to boost your willpower? Check out these five tips from HuffPost blogger Christine Carter, Ph.D.

Related on HuffPost:

Loading Slideshow...
  • Barack Obama

    Obama is a <a href="http://articles.washingtonpost.com/2012-09-25/politics/35496484_1_sasha-and-malia-michelle-obama-first-daughters" target="_blank">self-proclaimed night owl</a> -- but he wakes up early to <a href="http://www.cbsnews.com/8301-505125_162-37440325/how-president-obama-spends-his-other-8-hours/" target="_blank">squeeze in a workout</a> before getting in to the office at 8:30 a.m. or 9 a.m. "Health is obviously important to Obama," <a href="http://www.cbsnews.com/8301-505125_162-37440325/how-president-obama-spends-his-other-8-hours/" target="_blank">writes Robert Pagliarini of CBS News</a>. "So much so that it's the first thing he does in the morning. He doesn't hope to squeeze in a workout if he has time, he ensures he has time by doing it first thing."

  • Anna Wintour

    Before her daily blow-out at a quarter til seven to perfect that famous coif, Vogue editor-in-chief Anna Wintour reportedly starts her day with a rousing 5:45 a.m. tennis match, <a href="http://www.theguardian.com/lifeandstyle/2007/nov/12/fashion.jesscartnermorley" target="_blank">according to The Guardian</a>.

  • Margaret Thatcher

    The Iron Lady -- who famously ran on around four hours of sleep -- would stay up until two or three in the morning with her officials working on speeches, <a href="http://www.bbc.co.uk/news/magazine-22084671" target="_blank">according to the BBC</a>. But she would still be up by 5 a.m. to listen to "Farming Today," a popular broadcast program on BBC Radio 4. (While Thatcher is a suspected <a href="http://www.webmd.com/sleep-disorders/features/7-myths-about-sleep" target="_blank">"short sleeper,"</a> <a href="http://www.huffingtonpost.com/news/@sleep123/" target="_blank">skimping on sleep</a> isn't healthy for the vast majority of people.)

  • Vladimir Nabokov

    Like many writers, the prolific Russian novelist said that he liked to start his work first thing in the morning. He described his writing habits at his home on Lake Geneva in an interview with The New York Times in 1968: “After waking up between six and seven in the morning, I write till 10:30, generally at a lectern which faces a bright corner of the room instead of the bright audiences of my professorial days," <a href="http://www.nytimes.com/books/97/03/02/lifetimes/nab-v-things.html" target="_blank">Nabokov told the Times</a> (looks like someone was ahead of the <a href="http://www.huffingtonpost.com/2012/09/03/readers-standing-desks_n_1841194.html" target="_blank">standing desk trend</a>). "The first half-hour of relaxation is breakfast with my wife around 8:30.”

  • Tim Armstrong

    The AOL CEO <a href="http://www.theguardian.com/money/2013/apr/01/what-time-ceos-start-day" target="_blank">told The Guardian</a> that he gets out of bed immediately when he wakes up at 5 or 5:15 in the morning, either to answer emails or sneak in a workout. "Historically, I would start sending emails when I got up," <a href="http://www.theguardian.com/money/2013/apr/01/what-time-ceos-start-day" target="_blank">he told The Guardian in April</a>. "But not everyone is on my time schedule, so I have tried to wait until 7 a.m. Before I email, I work out, read and use our products."

  • Gwyneth Paltrow

    Health comes first for actress-turned-wellness guru Gwyneth Paltrow, who wakes up at 4:30 a.m. to practice her asanas. ”I’m really not a morning person at all,” <a href="http://www.people.com/people/gwyneth_paltrow/" target="_blank">Paltrow told In Style</a>. ”It’s just sheer determination. I’m very strict with myself. When I practice six days a week and eat clean food, I feel much better.”

  • Frank Lloyd Wright

    The genre-defining architect came up with his best ideas between four and seven in the morning, <a href="http://www.amazon.com/Daily-Rituals-How-Artists-Work/dp/0307273601" target="_blank">according to Daily Rituals, Mason Curry's blog-turned-book</a> about the routines of famous artists. “I go to sleep promptly when I go to bed," Lloyd Wright explained to a friend, as documented in Daily Rituals. "Then I wake up around 4 a.m. and can’t sleep. But my mind’s clear, so I get up and work for three or four hours. Then I go to bed for another nap.”

  • Michelle Obama

    Like her husband, Mrs. Obama puts exercise at the top of her morning to-do list. The First Lady <a href="http://www.oprah.com/omagazine/Michelle-Obamas-Oprah-Interview-O-Magazine-Cover-with-Obama/8" target="_blank">told Oprah</a> that she wants her daughters to see her as a woman who takes care of herself, even if it means waking up at 4:30 a.m. to do it. "I just started thinking, if I had to get up to go to work, I'd get up and go to work," <a href="http://www.oprah.com/omagazine/Michelle-Obamas-Oprah-Interview-O-Magazine-Cover-with-Obama/8" target="_blank">Michelle said in an interview for O Magazine in 2009</a>. "If I had to get up to take care of my kids, I'd get up to do that. But when it comes to yourself, then it's suddenly, 'Oh, I can't get up at 4:30.' So I had to change that. If I don't exercise, I won't feel good. I'll get depressed."

  • Simone de Beauvoir

    "The Second Sex" author and feminist thinker Simone de Beauvoir -- who professed to not being a morning person -- <a href="http://www.theparisreview.org/interviews/4444/the-art-of-fiction-no-35-simone-de-beauvoir" target="_blank">said</a> she always started her day with a cup of tea before diving into writing. "I'm always in a hurry to get going," <a href="http://dailyroutines.typepad.com/daily_routines/2009/02/simone-de-beauvoir.html" target="_blank">she told The Paris Review in 1965</a>. I first have tea and then, at about 10, I get under way and work until one."

  • Robert Iger

    Disney CEO Robert Iger is also part of the 4:30 a.m. club, waking up bright and early to enjoy a little quiet time to himself. "It’s a time I can recharge my batteries a bit," <a href="http://www.nytimes.com/2009/05/03/business/03corner.html?pagewanted=all&_r=0" target="_blank">Iger told The New York Times in 2009</a>. "I exercise and I clear my head and I catch up on the world. I read papers. I look at e-mail. I surf the Web. I watch a little TV, all at the same time."