According to the article Does Money Really Affect Motivation, how does adding a reward to a task that is either interesting or uninteresting affect motivation?

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How much should people earn? Even if resources were unlimited, it would be difficult to stipulate your ideal salary. Intuitively, one would think that higher pay should produce better results, but scientific evidence indicates that the link between compensation, motivation and performance is much more complex. In fact, research suggests that even if we let people decide how much they should earn, they would probably not enjoy their job more.

Even those who highlight the motivational effects of money accept that pay alone is not sufficient. The basic questions are: Does money make our jobs more enjoyable? Or can higher salaries actually demotivate us?

Let's start with the first: does money engage us? The most compelling answer to this question is a meta-analysis by Tim Judge and colleagues. The authors reviewed 120 years of research to synthesize the findings from 92 quantitative studies. The combined dataset included over 15,000 individuals and 115 correlation coefficients.

The results indicate that the association between salary and job satisfaction is very weak. The reported correlation (r = .14) indicates that there is less than 2% overlap between pay and job satisfaction levels. Furthermore, the correlation between pay and pay satisfaction was only marginally higher (r = .22 or 4.8% overlap), indicating that people's satisfaction with their salary is mostly independent of their actual salary.

In addition, a cross-cultural comparison revealed that the relationship of pay with both job and pay satisfaction is pretty much the same everywhere (for example, there are no significant differences between the U.S., India, Australia, Britain, and Taiwan).

A similar pattern of results emerged when the authors carried out group-level (or between-sample) comparisons. In their words: "Employees earning salaries in the top half of our data range reported similar levels of job satisfaction to those employees earning salaries in the bottom-half of our data range" (p.162). This is consistent with Gallup's engagement research, which reports no significant difference in employee engagement by pay level. Gallup's findings are based on 1.4 million employees from 192 organizations across 49 industries and 34 nations.

These results have important implications for management: if we want an engaged workforce, money is clearly not the answer. In fact, if we want employees to be happy with their pay, money is not the answer. In a nutshell: money does not buy engagement.

But that doesn't answer the question: does money actually demotivate? Some have argued it does, that there is a natural tension between extrinsic and intrinsic motives, and that financial rewards can ultimately depress or "crowd out" intrinsic goals (e.g., enjoyment, sheer curiosity, learning or personal challenge).

Despite the overwhelming number of laboratory experiments carried out to evaluate this argument known as the overjustification effect there is still no consensus about the degree to which higher pay may demotivate. However, two articles deserve particular consideration.

The first is a classic meta-analysis by Edward Deci and colleagues. The authors synthesized the results from 128 controlled experiments. The results highlighted consistent negative effects of incentives from marshmallows to dollars on intrinsic motivation. These effects were particularly strong when the tasks were interesting or enjoyable rather than boring or meaningless.

More specifically, for every standard deviation increase in reward, intrinsic motivation for interesting tasks decreases by about 25%. When rewards are tangible and foreseeable (if subjects know in advance how much extra money they will receive) intrinsic motivation decreases by 36%. (Importantly, some have argued that for uninteresting tasks extrinsic rewards like money actually increase motivation. See, for instance, a meta-analysis by Judy Cameron and colleagues.) Deci et al's conclusion was that "strategies that focus primarily on the use of extrinsic rewards do, indeed, run a serious risk of diminishing rather than promoting intrinsic motivation" (p. 659).

The second article is a recent study by Yoon Jik Cho and James Perry. The authors analyzed real-world data from a representative sample of over 200,000 U.S. public sector employees. The results showed that employee engagement levels were three times more strongly related to intrinsic than extrinsic motives, but that both motives tend to cancel each other out. In other words, when employees have little interest in external rewards, their intrinsic motivation has a substantial positive effect on their engagement levels. However, when employees are focused on external rewards, the effects of intrinsic motives on engagement are significantly diminished. This means that employees who are intrinsically motivated are three times more engaged than employees who are extrinsically motivated (such as by money). Quite simply, you're more likely to like your job if you focus on the work itself, and less likely to enjoy it if you're focused on money. This finding was true even at low salary levels (remember, as per Gallup and Judge et al, there's no correlation between engagement and salary levels). Now, a skeptic might ask if this is just a correlation showing that people who don't like their jobs have nothing to think about other than the money. This is hard to test. Yes, that could be one reason; another could be that people who focus too much on money are preventing themselves from enjoying their jobs.

This research also begs the question: Is this a money-focused, engagement-eroding mindset one that employees can change? Or is does it reflect an innate mindset some people happen to be more focused on extrinsic rewards, while others are more focused on the task itself? We don't know. But my guess is that which you're focused on depends mostly on the match between your interests and skills and the tasks you've been given. And in theory, your mindset should be malleable the brain is remarkably plastic. We can try to teach people that if they focus on the task itself and try to identify positive aspects of the process, they will enjoy it more than if they are just focused on the consequences (rewards) of performing the task. The analogy here is that it's much more motivating to go for a run because it's fun than because I must get fit or lose some weight.

Intrinsic motivation is also a stronger predictor of job performance than extrinsic motivation so it is feasible to expect higher financial rewards to inhibit not only intrinsic motivation, but also job performance. The more people focus on their salaries, the less they will focus on satisfying their intellectual curiosity, learning new skills, or having fun, and those are the very things that make people perform best.

The fact that there is little evidence to show that money motivates us, and a great deal of evidence to suggest that it actually demotivates us, supports the idea that that there may be hidden costs associated with rewards. Of course, that doesn't mean that we should work for free. We all need to pay our bills and provide for our families but once these basic needs are covered the psychological benefits of money are questionable. In a widely cited paper, Daniel Kahneman and Angus Deaton reported that, in the U.S., emotional well-being levels increase with salary levels up to a salary of $75,000 but that they plateau afterwards. Or, as Arnold Schwarzenegger once stated: "Money doesn't make you happy. I now have $50 million but I was just as happy when I had $48 million."

But one size does not fit all. Our relationship to money is highly idiosyncratic. Indeed, in the era of personalization, when most things can now be customized to fit our needs from social media feeds to potential dates, to online shopping displays and playlists it is somewhat surprising that compensation systems are still based on the premise that what works for some people will also work for everyone else.

Other than its functional exchange value, pay is a psychological symbol, and the meaning of money is largely subjective. For example, there are marked individual differences in people's tendency to think or worry about money, and different people value money for different reasons (e.g., as a means to power, freedom, security, or love). If companies want to motivate their workforce, they need to understand what their employees really value and the answer is bound differ for each individual. Research shows that different values are differentially linked to engagement. For example, income goals based on the pursuit of power, narcissism, or overcoming self-doubt are less rewarding and effective than income goals based on the pursuit of security, family support, and leisure time. Perhaps it is time to compensate people not only according to what they know or do, but also for what they want.

Finally, other research shows that employees' personalities are much better predictors of engagement than their salaries. The most compelling study in this area is a large meta-analytic review of 25,000 participants, where personality determined 40% of the variability in ratings of job satisfaction. The more emotionally stable, extraverted, agreeable or conscientious people are, the more they tend to like their jobs (irrespective of their salaries). But the personality of employees' is not the most important determinant of their engagement levels. In fact, the biggest organizational cause of disengagement is incompetent leadership. Thus, as a manager, it's your personality that will have a significant impact on whether your employees are engaged at work, or not.