خود پاداش ها و انگیزه های شخصی

Self-administered rewards are ubiquitous. They serve as incentives for personal accomplishments and are widely recommended to increase personal motivation. We show that in a model with time-inconsistent and reference-dependent preferences, self-rewards can be a credible and effective tool to overcome self-control problems. We also discuss the different types of self-rewards the individual can use, such as vice goods and virtue goods, and analyze which types of goods the individual prefers.

The pleasure of the moment often seduces people to act against their own long run interests. Many individuals are tempted to shirk on unpleasant tasks – such as studying for an exam, writing a report, dieting, or saving money. If a person with such a present-bias anticipates the intrapersonal conflict, this gives scope for self-regulation (e.g., Laibson, 1997 and O׳Donoghue and Rabin, 1999). One form of self-regulation is the use of self-rewards or self-punishments. To help reach their goals, people frequently promise themselves a reward if they persist and accomplish a particular task. Consumer researchers have documented a wide-spread use of such “self-gifts” as incentives for personal accomplishments (e.g., Mick and DeMoss, 1990 and Mick and Faure, 1998). Self-rewards are also recommended in self-help guides and figure prominently in the professional treatment of problem behaviors (e.g., Bandura, 1971, Febbraro and Clum, 1998, Faber and Vohs, 2004 and Clum and Watkins, 2007). Even firms invest into “self-leadership” training programs, to teach their employees how to increase their motivation with self-rewards (e.g., Vancouver and Day, 2005). But how do self-rewards work and what are their limits? It has to be credible that the person does not take the self-reward after failing to reach the goal, and that the person does not forgo to take it after reaching the goal. And why do people sometimes succeed with quite mundane self-rewards (such as a cup of coffee or a game of pinball) but on other occasions treat themselves to a luxury good they would normally consider too extravagant (such as an expensive pair of shoes or an exclusive bottle of wine)? To address these questions we develop a model of self-regulation through goal setting and self-rewards. We show that a self-reward makes an individual pursue more challenging goals than she otherwise would. And we analyze how and when different kinds of rewards help the individual overcome a self-control problem. A crucial element of the model is that the promise of a self-reward shapes expectations. The promise of a self-reward conditional on meeting a goal means that buying the good after achieving the goal is something the individual expected to happen; whereas buying it after missing the goal goes against what she expected. Whether expectations are met or not matters. According to Kőszegi and Rabin (2006a), past expectations become reference points against which people evaluate outcomes, such as the benefit of a good and the price to be paid for it. In these evaluations, people often display loss-aversion in the sense of Kahneman and Tversky׳s (1979) Prospect Theory. What reference points an individual forms, however, is not arbitrary. For an individual who is rational and forward-looking, in equilibrium, it must indeed be optimal (not) to buy the good if she expected (not) to buy it. To illustrate the consequences of these ideas for self-regulation, consider a self-reward strategy of the form “If I achieve [a specific goal], I׳ll buy [a certain good]; but if I do not stick to my goal, I will deny myself this good”. Now if the price of the good is very low, the individual will always buy it – no matter what her past expectations were. Hence, the part of the self-promise “… if I do not stick to my goal, I will deny myself the good” is not credible. So the individual rationally expects that she will buy the good, irrespective of the task outcome and the self-reward strategy unravels. Conversely, if the price of the good is very high, she knows that she will never buy it – so the part of the self-promise “If I achieve my goal, I׳ll buy that good …” is not credible. So again the self-reward strategy unravels. For an intermediate price range, buying as well as not buying can be a self-sustaining self-reward strategy. If the individual expects to buy the good she will buy it; if she expects not to buy the good she will not buy it. Thus, the promise that she will reward herself upon meeting her goal, but would deny herself the reward if she failed the goal is credible. To help overcome the self-control problem, the self-reward strategy must not only be credible but it must also provide appropriate incentives. Sticking to the goal and taking the reward must increase the continuation utility enough to offset the temptation to deviate from the goal and not to take the reward. The more severe the present bias is, or the higher the costs of effort, the stronger the incentives must be (i.e., the lower the price of the good must be). Otherwise, the reward is not attractive enough to overcome the self-control problem. Our framework also helps to understand the nature of self-reward goods. Different goods have a different motivational strength because they vary in terms of prices and their value to the individual. Vice goods (goods that tempt a present-biased individual because they confer immediate benefits and costs are delayed) motivate the individual the most, followed by neutral goods (goods where benefits and costs arise at the same time) and virtue goods (goods with delayed benefits and immediate costs). However, with vice goods it is the most difficult to prevent oneself from buying the good in case the goal is not met. Indeed, we show that a vice good has to be costly from an ex ante perspective, so that not buying it is credible after a failure to live up to the goal. Intuitively, abstaining from buying the good is not credible if the reward is a (relatively cheap) chocolate cake – the individual will consume this cake even if she did not stick to her goal. It needs to be the expensive bottle of St. Emilion wine – a bottle that the individual normally considers as too extravagant. The paper is organized as follows. After discussing the related literature we introduce the model in Section 2. Our main analysis and results are in Section 3. In Section 4, we analyze the different kinds of self-reward goods. Section 5 discusses robustness of our results to alternative assumptions such as partial naïveté or uncertainty. Section 6 concludes the paper. Related literature: Our main contribution is to the literature that deals with the question of how present-biased individuals cope with self-control problems (for an overview see, e.g., Brocas et al., 2004). A large body of work focuses on the role of external commitment technologies. It explains why people incur costs – for example by investing in illiquid assets, signing binding contracts, or making binding promises to other parties – in order to overcome self-control problems in savings and consumption decisions (e.g., Laibson, 1997), or to overcome low effort provision and procrastination (e.g., DellaVigna and Malmendier, 2004 and Carrillo and Dewatripont, 2008). While most instances of self-control in everyday life seem to occur without any extrinsic commitment at all (cf. Rachlin, 1995), only a few papers deal with intrapersonal strategies – as we do here. Benhabib and Bisin (2005) model the use of neural control processes, Bisin and Hyndman (2009) consider deadlines, Suvorov and van de Ven (2008), Koch and Nafziger (2011) and Hsiaw (2013) model goal setting, and Koch and Nafziger (2012) consider multiple goals and mental accounting. Our paper builds upon these goal setting models and shows how an individual can further alleviate her self-control problem by specifying not only goals, but also self-rewards. Bénabou and Tirole (2004) ask why personal rules can actually work. In their model, individuals have imperfect recall about past motives, and hence draw inference about these motives based on their past actions (like living up to a personal rule in a situation that puts their willpower to a test). Carrillo and Mariotti (2000) and Bénabou and Tirole (2002) model how the manipulation of self-confidence and self-esteem can serve as a self-regulation strategy. Unlike these papers, our analysis of self-rewards does not rely on reputation building. Asheim (1997) considers a different notion of self-reward. He notes that multiple subgame perfect equilibria may exist if a present-biased individual faces an infinite horizon decision problem, or if there are indifferences. He proposes a refinement and provides examples of decision rules that can be interpreted as incorporating self-reward or self-punishment.

Personal accomplishments and achieved goals are important reasons why people reward themselves, according to survey evidence by Mick and DeMoss (1990). Some examples of self-rewards they find are mundane consumption, like watching TV or having lunch with a friend. For instance, one woman motivates herself to do unpleasant household chores with a “promise [to] myself that if I get three rooms cleaned without a break, then I can put my feet up and watch a game show on television” (p. 326). Other examples they list have an indulgent character, like buying a whirlpool bath as reward for running a marathon. Such a motivation to consume luxury is also reflected in a KPMG survey in China, where over 60 percent of the respondents bought luxury goods as a way to reward themselves for their hard work and success (Debnam and Svinos, 2006). Our analysis sheds light on the power and limits of different types of self-reward goods. It shows why quite mundane goods often work well as self-rewards. Along these lines, self-help guides typically recommend how to start with thinking about suitable contingent rewards. You should use “small rewards” that are sufficiently enticing to help motivate yourself, but that are not so important to you that you would go ahead and get them even if you failed to achieve the prescribed targets. Examples would be “play a game of pinball” after finishing your homework or “have a nice dinner with your friends” after writing up a report.20 While our model suggests that tying the consumption of desirable neutral goods to achieving personal performance targets may often allow to overcome self-control problems in a costless manner, at least two caveats must be kept in mind. First, when there is substantial uncertainty (e.g., about the link between effort and performance – the case we analyzed), gambling on the consumption of reward goods will be undesirable. Moreover, overconfidence about one׳s capacity for self-control may often lead people to set excessively high goals, thereby increasing the risk of failure. Second, our analysis shows that a self-reward sometimes needs to have an indulgent character to be a sufficiently powerful motivator. Specifically, the model predicts that people may consume vice goods (as a self-reward) after being virtuous in a task. A common interpretation for such behavior is that the exertion of self-control in a task depletes self-control resources and that the individual therefore succumbs to temptation afterwards (cf. Muraven and Baumeister, 2000). Our results show that there is a second interpretation for such behavior. Rather than reflecting self-regulation failure, such behavior may be the expression of a successful self-regulation strategy. A recent experiment by Milkman et al. (2013) demonstrates that “want experiences” (similar to vice goods in our terminology) can be successfully bundled with “should behaviors” (i.e., those that are useful in the long run but require overcoming the present bias, as in our model). The evidence indeed suggests that such bundling, when successfully implemented, allows to both encourage the costly “should behaviors” and prevent the abuse of “want experiences”. Problems of self-regulation are important in many economic contexts. For example, self-regulation failure often leads to a poor diet (overeating of sinful products), or lacking exercise. And these contribute to the problem of obesity. The World Health Organization (WHO) reports that more than 1.4 billion adults were overweight in 2008, and more than half a billion were obese. The WHO estimates that at least 2.8 million people die each year as a result of being overweight or obese. Moreover, globally, the WHO attributes 44% of diabetes cases, 23% of ischaemic heart disease, and 7–41% of certain cancers to overweight and obesity.21 The associated health costs are large (cf. Finkelstein et al., 2009). Similarly, self-regulation failure leads to problems such as low study effort and school drop-out. The latter causes huge life time welfare losses at the individual level (cf. Oreopoulos, 2007), and also at the societal level because human capital accumulation is a key driver of economic growth. These examples illustrate that self-regulation failure can cause large economic costs. Our model helps to better understand when self-regulation without (often very costly) external commitment devices can be achieved. While our model also points to limitations of self-regulation, more research is needed to understand self-regulation failure. Our analysis has been cast as a personal problem. On the other hand, there are many jobs where routine employee supervision is limited, and the workers are largely responsible for motivating themselves. This has always been the case for many artistic and academic professions or self-employed entrepreneurs, but nowadays the issue becomes even more widespread. For instance, work at home is becoming increasingly popular. In 2005, 7% of workers in the European Union were working at home at least a quarter of their working time (Welz and Wolf, 2010). Similarly, around 10% of US workers work at least 1 day at home in a typical week; and work at home increase by roughly 35% from 1997 to 2010 (Mateyka et al., 2012). While work at home (or “telework” ) has many advantages, the primary concern is employee shirking (see, for instance, Bloom et al., 2013). Workplace arrangements in firms may serve as commitment devices for workers to mitigate self-control problems (Kaur et al., 2010).22 These commitment opportunities are reduced when working at home. Therefore, self-regulation is an important economic activity for those workers who have significant discretion in organizing their working time, and where immediate measures of performance are unavailable or not used for strategic reasons. By delegating responsibilities and decisions to employees, increasing their flexibility and discretion the employers increase the demand for employee self-regulation. On the other hand, this larger freedom creates not only challenges, but also additional opportunities for self-regulation. We believe that applying our model to self-regulation in the context of work and employer–employee relationships is an interesting direction for future research.