Part of the sequence: The Science of Winning at Life

My own behavior baffles me. I find myself doing what I hate, and not doing what I really want to do!

- Saint Paul (Romans 7:15)

Once you're trained in BayesCraft, it may be tempting to tackle classic problems "from scratch" with your new Rationality Powers. But often, it's more effective to do a bit of scholarship first and at least start from the state of our scientific knowledge on the subject.

Today, I want to tackle procrastination by summarizing what we know about it, and how to overcome it.

Let me begin with three character vignettes...

Eddie attended the sales seminar, read all the books, and repeated the self-affirmations in the mirror this morning. But he has yet to make his first sale. Rejection after rejection has demoralized him. He organizes his desk, surfs the internet, and puts off his cold calls until potential clients are leaving for the day.

Three blocks away, Valerie stares at a blank document in Microsoft Word. Her essay assignment on municipal politics, due tomorrow, is mind-numbingly dull. She decides she needs a break, texts some friends, watches a show, and finds herself even less motivated to write the paper than before. At 10pm she dives in, but the result reflects the time she put into it: it's terrible.

In the next apartment down, Tom is ahead of the game. He got his visa, bought his plane tickets, and booked time off for his vacation to the Dominican Republic. He still needs to reserve a hotel room, but that can be done anytime. Tom keeps pushing the task forward a week as he has more urgent things to do, and then forgets about it altogether. As he's packing, he remembers to book the room, but by now there are none left by the beach. When he arrives, he finds his room is 10 blocks from the beach and decorated with dead mosquitos.

Eddie, Valerie, and Tom are all procrastinators, but in different ways.¹

Eddie's problem is low expectancy. By now, he expects only failure. Eddie has low expectancy of success from making his next round of cold calls. Results from 39 procrastination studies show that low expectancy is a major cause of procrastination.² You doubt your ability to follow through with the diet. You don't expect to get the job. You really should be going out and meeting girls and learning to flirt better, but you expect only rejection now, so you procrastinate. You have learned to be helpless.

Valerie's problem is that her task has low value for her. We all put off what we dislike.³ It's easy to meet up with your friends for drinks or start playing a videogame; not so easy to start doing your taxes. This point may be obvious, but it's nice to see it confirmed in over a dozen scientific studies. We put off things we don't like to do.

But the strongest predictor of procrastination is Tom's problem: impulsiveness. It would have been easy for Tom to book the hotel in advance, but he kept getting distracted by more urgent or interesting things, and didn't remember to book the hotel until the last minute, which left him with a poor selection of rooms. Dozens of studies have shown that procrastination is closely tied to impulsiveness.⁴

Impulsiveness fits into a broader component of procrastination: time. An event's impact on our decisions decreases as its temporal distance from us increases.⁵ We are less motivated by delayed rewards than by immediate rewards, and the more impulsive you are, the more your motivation is affected by such delays.

Expectancy, value, delay, and impulsiveness are the four major components of procrastination. Piers Steel, a leading researcher on procrastination, explains:

Decrease the certainty or the size of a task's reward - its expectancy or its value - and you are unlikely to pursue its completion with any vigor. Increase the delay for the task's reward and our susceptibility to delay - impulsiveness - and motivation also dips.

The Procrastination Equation

This leaves us with "the procrastination equation":

Though we are always learning more, the procrastination equation accounts for every major finding on procrastination, and draws upon our best current theories of motivation.⁶

Increase the size of a task's reward (including both the pleasantness of doing the task and the value of its after-effects), and your motivation goes up. Increase the perceived odds of getting the reward, and your motivation also goes up.

You might have noticed that this part of the equation is one of the basic equations of the expected utility theory at the heart of economics. But one of the major criticisms of standard economic theory was that it did not account for time. For example, in 1991 George Akerlof pointed out that we irrationally find present costs more salient than future costs. This led to the flowering of behavioral economics, which integrates time (among other things).

Hence the denominator, which covers the effect of time on our motivation to do a task. The longer the delay before we reap a task's reward, the less motivated we are to do it. And the negative effect of this delay on our motivation is amplified by our level of impulsiveness. For highly impulsive people, delays do even greater damage to their motivation.

The Procrastination Equation in Action

As an example, consider the college student who must write a term paper.⁷ Unfortunately for her, colleges have created a perfect storm of procrastination components. First, though the value of the paper for her grades may be high, the more immediate value is very low, assuming she dreads writing papers as much as most college students do.⁸ Moreover, her expectancy is probably low. Measuring performance is hard, and any essay re-marked by another professor may get a very different grade: a B+ essay will get an A+ if she's lucky, or a C+ if she's unlucky.⁹ There is also a large delay, since the paper is due at the end of the semester. If our college student has an impulsive personality, the negative effect of this delay on her motivation to write the paper is greatly amplified. Writing a term paper is grueling (low value), the results are uncertain (low expectancy), and the deadline is far away (high delay).

But there's more. College dorms, and college campuses in general, might be the most distracting places on earth. There are always pleasures to be had (campus clubs, parties, relationships, games, events, alcohol) that are reliable, immediate, and intense. No wonder that the task of writing a term paper can't compete. These potent distractions amplify the negative effect of the delay in the task's reward and the negative effect of the student's level of impulsiveness. 

How to Beat Procrastination

Although much is known about the neurobiology behind procrastination, I won't cover that subject here.¹⁰ Instead, let's jump right to the solutions to our procrastination problem.

Once you know the procrastination equation, our general strategy is obvious. Since there is usually little you can do about the delay of a task's reward, we'll focus on the three terms of the procrastination equation over which we have some control. To beat procrastination, we need to:

1. Increase your expectancy of success.
2. Increase the task's value (make it more pleasant and rewarding).
3. Decrease your impulsiveness.

You might think these things are out of your control, but researchers have found several useful methods for achieving each of them.

Most of the advice below is taken from the best book on procrastination available, Piers Steel's The Procrastination Equation, which explains these methods and others in more detail.

Optimizing Optimism

If you don't think you can succeed, you'll have little motivation to do the task that needs doing. You've probably heard the advice to "Be positive!" But how? So far, researchers have identified three major techniques for increasing optimism: Success Spirals, Vicarious Victory, and Mental Contrasting.

Success Spirals

One way to build your optimism for success is to make use of success spirals.¹¹ When you achieve one challenging goal after another, your obviously gain confidence in your ability to succeed. So: give yourself a series of meaningful, challenging but achievable goals, and then achieve them! Set yourself up for success by doing things you know you can succeed at, again and again, to keep your confidence high.

Steel recommends that for starters, "it is often best to have process or learning goals rather than product or outcome goals. That is, the goals are acquiring or refining new skills or steps (the process) rather than winning or getting the highest score (the product)."¹²

Wilderness classes and adventure education (rafting, rock-climbing, camping, etc.) are excellent for this kind of thing.¹³ Learn a new skill, be it cooking or karate. Volunteer for more responsibilities at work or in your community. Push a favorite hobby to the next level. The key is to achieve one goal after another and pay attention to your successes.¹⁴ Your brain will reward you with increased expectancy for success, and therefore a better ability to beat procrastination.

Vicarious Victory

Pessimism and optimism are both contagious.¹⁵ Wherever you are, you probably have access to community groups that are great for fostering positivity: Toastmasters, Rotary, Elks, Shriners, and other local groups. I recommend you visit 5-10 such groups in your area and join the best one.

You can also boost your optimism by watching inspirational movies, reading inspirational biographies, and listening to motivational speakers.

Mental Contrasting

Many popular self-help books encourage creative visualization, the practice of regularly and vividly imagining what you want to achieve: a car, a career, an achievement. Surprisingly, research shows this method can actually drain your motivation.¹⁶

Unless, that is, you add a second crucial step: mental contrasting. After imagining what you want to achieve, mentally contrast that with where you are now. Visualize your old, rusty car and your small paycheck. This presents your current situation as an obstacle to be overcome to achieve your dreams, and jumpstarts planning and effort.¹⁷

Guarding Against Too Much Optimism

Finally, I should note that too much optimism can also be a problem,¹⁸ though this is less common. For example, too much optimism about how long a task will take may cause you to put it off until the last minute, which turns out to be too late. Something like Rhonda Byrne's The Secret may be too optimistic.

How can you guard against too much optimism? Plan for the worst but hope for the best.¹⁹ Pay attention to how you procrastinate, make backup plans for failure, but then use the methods in this article to succeed as much as possible.

Increasing Value

It's hard to be motivated to do something that doesn't have much value to us - or worse, is downright unpleasant. The good news is that value is to some degree constructed and relative. The malleability of value is a well-studied area called psychophysics,²⁰ and researchers have some advice for how we can inject value into necessary tasks.

Flow

If the task you're avoiding is boring, try to make it more difficult, right up to the point where the difficulty level matches your current skill, and you achieve "flow."²¹ This is what the state troopers of Super Troopers did: they devised strange games and challenges to make their boring job passable. Myrtle Young made her boring job at a potato chip factory more interesting and challenging by looking for potato chips that resembled celebrities and pulling them off the conveyor belts.

Meaning

It also helps to make sure tasks are connected to something you care about for its own sake,²² at least through a chain: you read the book so you can pass the test so you can get the grade so you can get the job you want and have a fulfilling career. Breaking the chain leaves a task feeling meaningless.

Energy

Obviously, tasks are harder when you don't have much energy.²³ Tackle tasks when you are most alert. This depends on your circadian rhythm,²⁴ but most people have the most energy during a period starting a few hours after they wake up and lasting 4 hours.²⁵ Also, make sure to get enough sleep and exercise regularly.²⁶

Other things that have worked for many people are:

• Drink lots of water.
• Stop eating anything that contains wheat and other grains.
• Use drugs (especially modafinil) as necessary.
• Do short but intense exercise once a week.
• When tired, splash cold water on your face or take a shower or do jumping jacks or go running.
• Listen to music that picks up your mood.
• De-clutter your life, because clutter is cognitively exhausting for your brain to process all day long.

Rewards

One obvious way to inject more value into a task is to reward yourself for completing it.²⁷

Also, mix bitter medicine with sweet honey. Pair a long-term interest with a short-term pleasure.²⁸ Find a workout partner whose company you enjoy. Treat yourself to a specialty coffee when doing your taxes. I bribe myself with Pinkberry frozen yogurt to do things I hate doing.

Passion

Of course, the most powerful way to increase the value of a task is to focus on doing what you love wherever possible. It doesn't take much extra motivation for me to research meta-ethics or write summaries of scientific self-help: that is what I love to do. Some people who love playing video games have made careers out of it. To figure out which career might be full of tasks that you love to do, taking a RIASEC personality test might help. In the USA, O*NET can help you find jobs that are in-demand and fit your personality.

Handling Impulsiveness

Impulsiveness is, on average, the biggest factor in procrastination. Here are two of Steel's (2010a) methods for dealing with impulsiveness.

Commit Now

Ulysses did not make it past the beautiful singing Sirens with willpower. Rather, he knew his weaknesses and so he committed in advance to sail past them: he literally tied himself to his ship's mast. Several forms of precommitment are useful in handling impulsiveness.²⁹

One method is to "throw away the key": Close off tempting alternatives. Many people see a productivity boost when they decide not to allow a TV in their home; I haven't owned one in years. But now, TV and more is available on the internet. To block that, you might need a tool like RescueTime. Or, unplug your router when you've got work to do.

Another method is to make failure really painful. The website stickK lets you set aside money you will lose if you don't meet your goal, and ensures that you have an outside referee to decide whether your met your goal or not. To "up the ante," set things up so that your money will go to an organization you hate if you fail. And have your chosen referee agree to post the details of your donation to Facebook if you don't meet your goal.

Set Goals

Hundreds of books stress SMART goals: goals that are Specific, Measurable, Attainable, Realistic, and Time-Anchored.³⁰ Is this recommendation backed by good research? Not quite. First, notice that Attainable is redundant with Realistic, and Specific is Redundant with Measurable and Time-Anchored. Second, important concepts are missing. Above, we emphasized the importance of goals that are challenging (and thus, lead to "flow") and meaningful (connected to things you desire for their own sake).

It's also important to break up goals into lots of smaller subgoals which, by themselves, are easier to achieve and have more immediate deadlines. Typically, daily goals are frequent enough, but it can also help to set an immediate goal to break you through the "getting started" threshold. Your first goal can be "Write the email to the producer," and your next goal can be the daily goal. Once that first, 5-minute task has been completed, you'll probably already be on your way to the larger daily goal, even if it takes 30 minutes or 2 hours.³¹

Also: Are your goals measuring inputs or outputs? Is your goal to spend 30 minutes on X or is it to produce final product X? Try it different ways for different tasks, and see what works for you.

Because we are creatures of habit, it helps to get into a routine.³² For example: Exercise at the same time, every day.

Conclusion

So there you have it. To beat procrastination, you need to increase your motivation to do each task on which you are tempted to procrastinate. To do that, you can (1) optimize your optimism for success on the task, (2) make the task more pleasant, and (3) take steps to overcome your impulsiveness. And to do each of those things, use the specific methods explained above (set goals, pre-commit, make use of success spirals, etc.).

A warning: Don't try to be perfect. Don't try to completely eliminate procrastination. Be real. Overregulation will make you unhappy. You'll have to find a balance.

But now you have the tools you need. Identify which parts of the procrastination equation need the most work in your situation, and figure out which methods for dealing with that part of the problem work best for you. Then, go out there and make yourself stronger, score that job, and help save the world!

(And, read The Procrastination Equation if you want more detail than I included here.)

Next post: My Algorithm for Beating Procrastination

Previous post: Scientific Self-Help: The State of Our Knowledge

Notes

¹ These are the fictional characters used to illustrate the procrastination equation in Steel (2010a).

² Expectancy corresponds most closely to the commonly measured trait of "self efficacy." The relatively strong correlation between low self-efficacy and procrastination (across 39 studies) is shown table 3 of Steel (2007).

³ In a recent post, Eliezer Yudkowsky claimed that "on a moment-to-moment basis, being in the middle of doing the work is usually less painful than being in the middle of procrastinating." Thus, "when you procrastinate, you're probably not procrastinating because of the pain of working." That might be true for Eliezer in particular, but studies on procrastination suggest it's not true for most people. The pain of doing a task is a major factor contributing to procrastination. This is known as the problem of task aversiveness (Brown 1991; Burka & Yuen 1983; Ellis & Knauss 1977), also known as the problem of task appeal (Harris & Sutton, 1983) or as the dysphoric affect (Milgram, Sroloff, & Rosenbaum, 1988). For an overview of additional literature demonstrating this point, see page 75 of Steel (2007).

⁴ For an overview of the correlation between impulsiveness and procrastination, see pages 76-79 and 81 of Steel (2007).

⁵ This is recognized as one of the psychological laws of learning (Schwawrtz, 1989), and plays a role in the dominant economic role of discounted utility (Loewenstein & Elster, 1992). In particular, see the work on temporal construal theory (Trope & Liberman, 2003).

⁶ The procrastination equation is called temporal motivational theory (TMT). See Steel (2007) on how TMT accounts for every major finding on procrastination. See Steel & Konig (2006) on how TMT draws upon and integrates our best psychological theories of motivation. There are other theories of procrastination - the most popular may be the decisional-avoidant-arousal theory proposed by Ferrari (1992). But a recent meta-analysis shows that TMT is more consistent with the data (Steel, 2010b). An important note is that the full version of TMT places a constant in the denominator to prevent the denominator from skyrocketing into infinity as delay approaches 0. Also, 'impulsiveness' here is a substitute for 'susceptibility to delay,' something which may vary by task, whereas 'impulsiveness' sounds like a stable character trait that might not help to explain having different motivations to perform different tasks.

⁷ This example taken from Steel (2010a). Academic procrastination is the most-studied kind of procrastination (McCown & Roberts, 1994).

⁸ Even George Orwell hated writing. He wrote: "Writing a book is a horrible, exhausting struggle, like a long bout of some painful illness."

⁹ See Cannings et al. (2005) and Newstead (2002).

¹⁰ Read chapter 3 of Steel (2010a).

¹¹ In business academia, success spirals are known as "efficacy-performance spirals" or "efficacy-performance deviation amplifying loops". See Lindsley et al. (1995).

¹² See Steel (2010a), note 9 in chapter 7.

¹³ See Hans (2000), Feldman & Matjasko (2005), and World Organization of the Scout Movement (1998).

¹⁴ Zimmerman (2002).

¹⁵ Aarts et al. (2008), Armitage & Conner (2001), Rivs & Sheeran (2003), van Knippenberg et al. (2004).

¹⁶ Levin & Spei (2004), Rhue & Lynn (1987), Schneider (2001), Waldo & Merritt (2000).

¹⁷ Achtziger et al. (2008), Oettingen et al. (2005), Oettingen & Thorpe (2006), Kavanagh et al. (2005), Pham & Taylor (1999).

¹⁸ Sigall et al. (2000).

¹⁹ Aspinwall (2005).

²⁰ A good overview is Weber (2003).

²¹ Csikszentmihalyi (1990).

²² Miller & Brickman (2004), Schraw & Lehman (2001), Wolters (2003).

²³ Steel (2007), Gropel & Steel (2008).

²⁴ Furnham (2002).

²⁵ Klein (2009).

²⁶ Oaten & Cheng (2006).

²⁷ Bandura (1976), Febbraro & Clum (1998), Ferrari & Emmons (1995). This is known as learned industriousness, impulse pairing or impulse fusion. See Eisenberger (1992), Renninger (2000), Stromer et al. (2000).

²⁸ Ainslie (1992).

²⁹ Ariely & Wertenbroch (2002) and Schelling (1992).

³⁰ Locke & Latham (2002).

³¹ Gropel & Steel (2008), Steel (2010a).

³² Diefendorff et al. (2006), Gollwitzer (1996), Silver (1974).

References

Aarts, Dijksterhuis, & Dik (2008). Goal contagion: Inferring goals from others' actions - and what it leads to. In Shah & Gardner (Eds.), Handbook of motivation (pp. 265-280). New York: Guilford Press.

Achtziger, Fehr, Oettingen, Gollwitzer, & Rockstroh (2008). Strategies of intention formation are reflected in continuous MEG activity. Social Neuroscience, 4(1), 1-17.

Ainslie (1992). Picoeconomics: The strategic interaction of successive motivational states within the person. New York: Cambridge University Press.

Ariely & Wertenbroch (2002). Procrastination, deadlines, and performance: Self-control by precommitment. Psychological Science, 13(3): 219-224.

Armitage & Conner (2001). Efficacy of the theory of planned behavior: A meta-analytic review. British Journal of Social Psychology, 40(4): 471-499.

Aspinwall (2005). The psychology of future-oriented thinking: From achievement to proactive coping, adaptation, and aging. Motivation and Emotion, 29(4): 203-235.

Bandura (1976). Self-reinforcement: Theoretical and methodological considerations. Behaviorism, 4(2): 135-155.

Brown (1991). Helping students confront and deal with stress and procrastination. Journal of College Student Psychotherapy, 6: 87-102.

Burka & Yuen (1983). Procrastination: Why you do it, what to do about it. Reading, MA: Addison-Wesley.

Cannings, Hawthorne, Hood, & Houston (2005). Putting double marking to the test: a framework to assess if it is worth the trouble. Medical Education, 39(3): 299-308.

Csikszentmihalyi (1990). Flow: The psychology of optimal experience. New York: Harper & Row.

Diefendorff, Richard, & Gosserand (2006). Examination of situational and attitudinal moderators of the hesitation and performance relation. Personnel Psychology, 59: 365-393.

Eisenberger (1992). Learned industriousness. Psychological Review, 99: 248-267.

Ellis & Knauss (1977). Overcoming procrastination. New York: Signet Books.

Febbraro & Clum (1998). Meta-analytic investigation of the effectiveness of self-regulatory components in the treatment of adult problem behaviors. Clinical Psychology Review, 18(2): 143-161.

Feldman & Matjasko (2005). The role of school-based extracurricular activities in adolescent development: A comprehensive review and future directions. Review of Educational Research, 75(2), 159-210.

Ferrari (1992). Psychometric validation of two procrastination inventoriesfor adults: Arousal and avoidance measures. Journal of Psychopathology and Behavioral Assessment, 14(2): 97–110.

Ferrari & Emmons (1995). Methods of procrastination and their relation to self-control and self-reinforcement: An exploratory study. Journal of Social Behavior & Personality, 10(1): 135-142.

Furnham (2002). Personality at work: The role of individual differences in the workplace. New York: Routledge.

Gollwitzer (1996). The volitional benefits from planning. In Gollwitzer & Bargh (Eds.), The psychology of action: Linking cognition and motivation to behavior (pp. 287-312). New York: Guilford Press.

Gropel & Steel (2008). A mega-trial investigation of goal setting, interest enhancement, and energy on procrastination. Personality and Individual Differences, 45: 406-411.

Hans (2000). A meta-analysis of the effects of adventure programming on locus of control. Journal of Contemporary Psychotherapy, 30(1): 33-60.

Harris & Sutton (1983). Task procrastination in organizations: A framework for research. Human Relations, 36: 987-995.

Kavanagh, Andrade, & May (2005). Imaginary relish and exquisite torture: The elaborated intrusion theory of desire. Psychological Review, 112(2), 446-467.

Klein (2009). The secret pulse of time: Making sense of life's scarcest commodity. Cambridge, MA: Da Capo Lifelong Books.

Levin & Spei (2004). Relationship of purported measures of pathological and nonpathological dissociation to self-reported psychological distress and fantasy immersion. Assessment, 11(2): 160-168.

Lindsley, Brass, & Thomas (1995). Efficacy-performance spirals: A multilevel perspective. Academy of Management Review, 20(3): 645-678.

Locke & Latham (2002). Building a practically useful theory of goal setting and task motivation: A 35-year odyssey. American Psychologist, 57(9): 705-717.

Loewenstein & Elster (1992). The fall and rise of psychological explanations in the economics of intertemporal choice. In Loewenstein & Elster (Eds.), Choice over time (pp. 3-34). New York: Russell Sage Foundation.

McCown & Roberts (1994). A study of academic and work-related dysfunctioning relevant to the college version of an indirect measure of impulsive behavior. Integra Technical Paper 94-28, Radnor, PA: Integra, Inc.

Milgram, Sroloff, & Rosenbaum (1988). The procrastination of everyday life. Journal of Research in Personality, 22: 197-212.

Miller & Brickman (2004). A model of future-oriented motivation and self-regulation. Educational Psychology Review, 16(1): 9-33.

Newstead (2002). Examining the examiners: Why are we so bad at assessing students? Psychology Learning and Teaching, 2(2): 70-75.

Oaten & Cheng (2006). Longitudinal gains in self-regulation from regular physical exercise. British Journal of Health Psychology, 11(4): 713-733.

Oettingen, Mayer, Thorpe, Janatzke, & Lorenz (2005). Turning fantasies about positive and negative futures into self-improvement goals. Motivation and Emotion, 29(4): 236-266.

Oettingen & Thorpe (2006). Fantasy realization and the bridging of time. In Sanna & Chang (Eds.), Judgments over time: The interplay of thoughts, feelings, and behaviors (pp. 120-143). Oxford: Oxford University Press.

Pham & Taylor (1999). From thought to action: Effects of process- versus outcome-based mental simulations on performance. Personality and Social Psychology Bulletin, 25: 250-260.

Renninger (2000). Individual interest and its implications for understanding intrinsic motivation. In Sansone & Harackiewicz (Eds.), Inntrinsic and extrinsic motivation: The search for optimal motivation and performance (pp. 373-404). San Diego, CA: Academic Press.

Rhue & Lynn (1987). Fantasy proneness: The ability to hallucinate "as real as real." British Journal of Experimental and Clinical Hypnosis, 4: 173-180.

Rivis & Sheeran (2003). Descriptive norms as an additional predictor in the theory of planned behaviour: A meta-analysis. Current Psychology, 22(3), 218-233.

Schelling (1992). Self-command: A new discipline. In Loewenstein & Elster (Eds.), Choice over time (pp. 167-176). New York: Russell Sage Foundation.

Schneider (2001). In search of realistic optimism: Meaning, knowledge, and warm fuzziness. American Psychologist, 56(3): 250-263.

Schraw & Lehman (2001). Situational interest: A review of the literature and directions for future research. Educational Psychology Review, 13(1): 23-52.

Schwartz (1989). Psychology of learning and behavior (3rd ed.). New York: Norton.

Sigall, Kruglanski, & Fyock (2000). Wishful thinking and procrastination. Journal of Social Behavior & Personality, 15(5): 283-296.

Silver (1974). Procrastination. Centerpoint, 1(1): 49-54.

Steel (2007). The nature of procrastination. Psychological Bulletin, 133(1): 65-94.

Steel (2010a). The Procrastination Equation. New York: Harper.

Steel (2010b). Arousal, avoidant and decisional procrastinators: Do they exist? Personality and Individual Differences, 48: 926-934.

Steel & Konig (2006). Integrating theories of motivation. Academy of Management Review, 31(4): 889-913. 

Trope & Liberman (2003). Temporal construal. Psychological Review, 110: 403-421.

van Knippenberg, van Nippenberg, De Cremer, & Hegg (2004). Leadership, self, and identity: A review and research agenda. The Leadership Quarterly, 15(6), 825-856.

Waldo & Merritt (2000). Fantasy proneness, dissociation, and DSM-IV axis II symptomatology. Journal of Abnormal Psychology, 109(3): 555-558.

Weber (2003). Perception matters: Psychophysics for economists. In Brocas & Carrillo (Eds.), The Psychology of Economic Decisions (Vol. II). New York: Oxford University Press.

Wolters (2003). Understanding procrastination from a self-regulated learning perspective. Journal of Educational Psychology, 95(1): 179-187.

World Organization of the Scout Movement (1998). Scouting: An educational system. Geneva, Switzerland: World Scout Bureau.

Zimmerman (2002). Becoming a self-regulated learner: An overview. Theory into Practice, 41(2): 64-70.