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The overjustification effect

Author: Dr Simon Moss


Sometimes, individuals feel less motivated to engage in a task after, rather than before, incentives are offered. That is, the provision of incentives, such as rewards or punishments, can actually diminish the enjoyment that individuals experience. Individuals are less inclined to cherish the activity ( for a review, see Deci, Koestner, & Ryan, 1999).

This tendency is called the overjustification effect (e.g., Morgan, 1981) as well as the undermining effect, the hidden cost of reward (Lepper & Greene, 1978), and the corruption effect. In the literature on economics, this effect is discussed under the rubric of crowding theory (Frey, 1997, 2001& Frey & Jegen, 2000).

According to self determination theory, individuals sometimes engage in a task that is inherently fulfilling, enjoyable, and interesting. In other occasions, individuals engage in a task merely to attain some reward or circumvent some punishment, called extrinsic motivation. When these extrinsic motivations are salient, the inherent sense of fulfillment, enjoyment, and interest in the task is not as conspicuous (see Lepper , 1981). Absorption in the task wanes& persistence or creativity can diminish as well.


To illustrate the overjustification effect, in one study, conducted by Gneezy and Rustichini (2000), participants were instructed to complete a few simple tasks, such as collect donations. Some of the participants were offered a specific amount to participate. They were then asked to complete as many tasks as possible. Other participants were offered a smaller amount plus an incentive, depending on the number of tasks they completed. Usually, the number of tasks that participants completed diminished when an incentive was offered. The incentive may have curbed the perceived enjoyment of these tasks.

A meta-analysis, undertaken by Cameron and Pierce (1994), challenged the legitimacy of this overjustification effect. Nevertheless, Deci, Koestner, and Ryan (1999) uncovered some limitations of this meta-analysis. First, Cameron and Pierce (1994) omitted 20% of the relevant studies, touting these projects as outliers. Second, Cameron and Pierce (1994) included studies in which the tasks were tedious or monotonous. Nevertheless, few researchers ever maintained that incentives reduce the perceived enjoyment of tedious tasks.

Indeed Deci, Koestner, and Ryan (1999) undertook a larger meta-analysis that circumvents these limitations. Overall, 128 studies, published between 1971 and 1997, were subjected to this analysis. They discovered that tangible incentives do indeed reduce the intrinsic fascination and motivation to engage in tasks that are inherently interesting. The effect size was moderate.

Deci, Koestner, and Ryan (1999) uncovered some other interesting principles. For example, the effect is stronger when the incentives revolve around money rather than other symbolic rewards. Furthermore, as this interest declines, performance can also dissipate--especially if the tasks are complex. Finally, if individuals feel they are likely to receive the rewards, the overjustification effect is especially pronounced.

Focus on benefits instead of experience

When people focus on the outcomes they would enjoy if a goal was fulfilled, they may become more inclined to initiate some behavior but their persistence declines. This focus on outcomes could reinforce an extrinsic motivation and, therefore, represent an overjustification effect.

To illustrate, in one study, reported by Fishbach and Choi (2012), some participants were told to describe the benefits of exercising on a treadmill, such as losing weight. Then, during their exercise, they continued to reflect upon these benefits. Other participants, in contrast, we're asked to describe the experience of exercising, such as the activities they need to undertake and the feelings they may endure. Again, during the exercise, they continued to reflect upon these experiences.

Furthermore, participants were also asked to predict the duration they will exercise on the treadmill. Relative to the other individuals, the participants who focused on the benefits predicted they will exercise more extensively but were actually less persistent. Presumably, when individuals focus on these benefits, they feel this exercise is not inherently engaging. That is, they feel they have engaged in this act to achieve some benefit. Consequently, the task feels arduous.

Several other studies confirm this premise. In the second study, participants reflected on the benefits or experience of origami. While observing this activity, individuals were especially likely to perceive this task as interesting if they reflected upon the benefits. However, while completing this activity, individuals were more likely to perceive this task as interesting if they reflected upon the experience (Fishbach & Choi, 2012). Similarly, reflecting upon the benefits of dental floss initially increased the likelihood that individuals will floss. But, after a few days, this focus on benefits diminished persistence (Fishbach & Choi, 2012).

Mechanisms that underpin the overjustification effect

These observations can be ascribed to self determination theory (Deci & Ryan, 1995& Deci, Koestner, & Ryan, 1999). In particular, tangible incentives imply external interventions. As a consequence, individuals feel their autonomy is compromised and hence their intrinsic needs are not fulfilled. Similarly, the tangible incentives might also imply the person is not competent or motivated to engage in the task otherwise& their need to feel competent is not satisfied. Finally, the tangible incentives do not enable the individual to demonstrate their behavior is altruistic& their capacity to fulfill their need to develop relationships is also challenged.

These considerations imply that tangible incentives will curb intrinsic motivation, but only in specific circumstances. If the incentives are perceived as supportive--reinforcing the natural preferences of individuals, for example--these problems dissipate.

Kivetz (2005) uncovered some evidence of this proposition. This study showed that individuals who reviewed books preferred to be rewarded with more books, whereas individuals who reviewed songs preferred to be rewarded with music CDs . Rewards that match the task imply the activity is indeed inherently interesting, eliciting intrinsic motivation, and potentially improving performance.


James (2005), however, showed how this overjustification or crowding effect can be reconciled with utility functions, derived from a Benthamite interpretation of utility. That is, as James explains, when tangible incentives are offered, withdrawing intrinsic motivation actually increases their overall satisfaction or experiential utility, representing a web of pleasure, pain, feelings, emotions, and thoughts.

To clarify, any events that fulfill the fundamental needs of individuals--autonomy, competence, or relatedness--tend to increase intrinsic motivation. In contrast, events that curb autonomy, competence, and relatedness decrease intrinsic motivation. Incentives often control or restrict the behavior of individuals, curtailing autonomy, and thus reducing intrinsic motivation. However, if any sensitivity or awareness of intrinsic motivation is disregarded, the deleterious effects of incentives abates. Thus, if people neglect intrinsic motivation, and do not even seek their fundamental needs, overall satisfaction is actually maximized in some sense. The problems with these incentives are, in essence, disregarded.

A key implication of this model is that incentives will not always compromise intrinsic motivation. That is, if the incentive does not curb autonomy, individuals may recognize the event is germane to intrinsic motivation. They may feel this event increases intrinsic, in addition to extrinsic, motivation.

However, large incentives are especially likely to curb a sense of autonomy and thus reduce intrinsic motivation (for evidence, see Newman & Layton, 1984). That is, because these incentives are conspicuous, individuals ascribe their efforts to the prospect of these rewards. They do not experience a sense of choice. They feel governed by the incentives. To maximize their utility, their sensitivity to intrinsic motivation will diminish.

In contrast, some incentives can increase intrinsic motivation. That is, sometimes individuals feel motivated by general norms, like the passion to complete tasks well. In these instances, rewards can sometimes be perceived as an affirmation these individuals have fulfilled these norms, Some of these preferences align with prevalent microeconomic theory. For instance, many economists also feel that government intervention is necessary when the service could generate harmful byproducts, like contaminants, and when the private supplier is a monopoly. Nevertheless, the preference towards government intervention when the service revolves around health does not necessarily align to microeconomic theory.

Task variation

As Smith, Wagaman, and Handley (2009) argue, tangible rewards, like prizes, might also reduce the likelihood that individuals attempt to modify their tasks as an attempt to enhance enjoyment. That is, when individuals complete an activity, they often introduce minor changes to overcome tedium and improve interest. However, when tangible rewards are offered, their attention is not as likely to be directed towards their experience of interest (Ryan & Deci, 2000). Consequently, they might become less inclined to vary their tasks appropriately.

Conscious deliberation versus unconscious processes

According to Bijleveld, Custers, and Aarts (2011), tangible rewards, such as money, will often increase the effort that individuals devote to tasks. Conceivably, this effort can evoke cognitive strategies that impair task performance. For example, when people devote effort to their tasks, they tend to deliberate carefully, analyzing all the features and facets of a task methodically. This mindset can undermine performance on some tasks, especially activities that demand intuition (see unconscious thinking theory and cognitive experiential self theory) as well as flexibility.

Nevertheless, if the tangible rewards are subliminal--for example, if photographs of money are presented too rapidly to be recognized consciously--these problems may subside. Specifically, subliminal money might activate various cognitive systems without modifying the cognitive strategies that individuals apply.

These possibilities were confirmed by Bijleveld, Custers, and Aarts (2011). In their study, participants completed an attentional blink task. In particular, on each trial, a series of characters was presented rapidly, one every 100 ms. Two of these characters were numbers, and the remaining characters were letters. After each trial, participants has to specify the two numbers. This task is simple, except when the numbers appear within 200 and 500 ms of each other. On these trials, people often fixate on the first number and therefore disregard the second number.

At the beginning of each trial, a picture of a coin also appeared. The coin was either sizeable in value, 50 cents, or negligible in value, 1 cent. Furthermore, the coin was presented for either 300 ms, and was thus recognized consciously, or 20 ms, and was thus subliminal and not recognized consciously.

If the coin was visible, the value of this money did not affect performance. If the coin was subliminal, the value of this money did affect performance: participants performed better when the coin was valuable. According to Bijleveld, Custers, and Aarts (2011), the subliminal coin might activate subcortical regions, such as the ventral striatum. When these regions are activated, individuals feel, unconsciously, the task is important, promoting effort and mobilizing prefrontal areas of the brain. However, the goal to improve effort is not conscious, and hence the cognitive strategies that individuals utilize are not modified.

Effects of money on enjoyment

The overjustification hypothesis implies that rewards can curb enjoyment. Indeed, as Quoidbach, Dunn, Petrides, and Mikolajczak (2010) demonstrated, even exposure to money has been shown to diminish the level of enjoyment that individuals derive from specific pleasures. In one study, for example, participants were asked to imagine various positive experiences, such as observing a waterfall. They were then asked to estimate the likelihood they would engage in various behaviors that have been shown to prolong positive emotions, such as maintain their concentration on the event or communicate this event to other people. Wealthier people were less inclined to engage in these behaviors.

In a subsequent study, participants were granted an opportunity to savor a piece of chocolate. That is, the time they dedicated to eating the chocolate was regarded as a measuring of savoring. If participants had been exposed to a photograph in which money was prominent, they were less likely to savor the chocolate soon afterwards (Quoidbach, Dunn, Petrides, & Mikolajczak, 2010).

In the final chapter of his book, Ariely (2009) also reported a study, conducted with Uri Gneezy, George Loewenstein, and Nina Mazar, that shows how large financial rewards also compromise performance, especially on complex tasks. In one of these studies, participants were granted the opportunity to earn a large bonus of $600 or a smaller bonus of $60 to perform two tasks, each demanding four minutes of their time. One of the tasks was simple and repetitive: Participants merely needed to tap a keypad as rapidly as possible. The other task was more complex, demanding more advanced cognitive operations: Participants needed to perform arithmetic. The larger bonus compromised performance on the complex task, but enhanced performance on the simple task.

Observations in children

The overjustification effect has also been observed in children. Lepper, Greene, and Nisbett (1973), for example, demonstrated this effect in children aged between 3 and 4. In this activity, children engaged in a pleasurable drawing task. Soon afterwards, only some of the children were promised a reward if they continue to draw. After this period, all children were granted more time to draw. Children who had been rewarded to draw previously were not as inclined to persist with this task later.

The overjustification effect has also been observed in 20-month-old infants. In particular, Warneken and Tomasello (2008) examined the extent to which these infants engage in helping behavior. Most of the infants did demonstrate a natural inclination to help. Later, some of the infants received a material reward to help& other infants received no reward or praise instead. Relative to the other infants, the infants who had received the material rewards were less inclined to help afterwards.

Specifically, in this study, the experimenter performed various activities at her desk. During this time, she dropped at object onto the floor, putatively by accident. She attempted to retrieve the object with her outstretched hand, emitting sounds that emphasized her effort and inability to reach. A similar procedure was repeated six times. The number of times the child retrieved the object for the experimenter represented a measure of helping.

Some of the children received a material reward if they helped: They were offered a toy cube, for example. Some of the children were praised, with phrases like "Thank you& that's really nice". Other children did not receive any reward or praise. The material reward was shown to curb the likelihood of subsequent helping.

Factors that moderate the overjustification effect

Measures of intrinsic motivation

The overjustification or undermining effect depends on the measure that is used to assess intrinsic motivation. To illustrate, sometimes to gauge intrinsic motivation, researchers examine the length of time that participants devote to a task voluntarily. Alternatively, researchers might ask participants to evaluate the extent to which they enjoyed the activity or perceived the activity as interesting. That is, participants might complete the Intrinsic Motivation Inventory (e.g., Plant & Ryan, 1985& Ryan, 1982). One of the subscales, for example, determines the extent to which individuals perceive the task as interesting or enjoyable. Typical items include "This activity was fun to do". Wiechman and Gurland (2009) reported an internal consistency of .91.

Interestingly, tangible rewards can markedly diminish the time that individuals devote to this task later. These rewards, however, do not affect perceptions of enjoyment or interest as appreciably (see Deci, Koestner, & Ryan, 1999& e.g., Wiechman & Gurland, 2009). Conceivably, according to Deci, Koestner, and Ryan (1999), evaluations of enjoyment and interest might not be as precise. In particular, participants might confuse their enjoyment of the reward with the enjoyment of the task itself.


Wiechman and Gurland (2009) argued that effects of tangible rewards on intrinsic motivation might vary across time. To assess this proposition, participants undertook a task in which they need to locate a instances of a name--Nina--embedded within various drawings by Al Hirschfeld. Only a subset of participants received money every time they located this name.

One week later, participants returned. The experimenter feigned a need to visit the restroom. The experimenter told participants they could undertake the activity to locate the name Nina or read other material. The experimenter then returned three minutes later. This experiment was unique in that participants were granted only a maximum of three minutes to engage in the target activity.

During this three minutes, participants who had not received the tangible reward tended to attempt the target activity--to locate instances of the name Nina--to a moderate extent. In contrast, participants who had not received this reward tended either to disregard the activity altogether or dedicate most of the time to this task. In other words, the tangible reward either increased or decreased the time that participants dedicated to this activity.

According to Wiechman and Gurland (2009), some participants might show the traditional overjustification effect almost immediately. Other participants, in contrast, might initially experience pressured persistence (Ryan, Koestner, & Deci, 1991)--an obligation to maintain their effort rather than bona fide intrinsic motivation. This pressure most likely dissipates after a few minutes, however.

Alternative explanations

Gneezy and Rustichini (2000) suggested that incentives may clarify the expectations of individuals. Without incentives, individuals must derive expectations from another source, such as social norms. Sometimes, these social norms are steep, increasing the perceived effort that is required.


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Last Update: 7/12/2016