Why Sales Incentives Often Fail to Drive Lasting Behaviors: The Science of Unpredictable Rewards

Incentives in sales are a classic tool for driving behaviors. The logic is simple: offer rewards, and people will be motivated to perform. Yet, in practice, sales incentives often don’t have the transformational impact organizations hope for. If incentives alone could drive growth, then every organization could turn a profit simply by boosting sales bonuses. But the reality is far more complex, and understanding why requires a look at how our brains respond to rewards, particularly the role of unpredictability in motivation.

The Human Need for Certainty—and When It’s Overrated

As humans, we like to know what to expect. When we’re waiting for a cab, for example, it’s far less frustrating when we know the estimated wait time. The same goes for the workplace: employees tend to feel more engaged and motivated when they know what’s coming, whether it’s stability in their roles or clarity in their goals. Uncertainty, as seen during times of crisis like the Covid-19 pandemic, often causes discomfort and stress.

However, there’s a twist. While humans generally crave certainty, studies in behavioral science have found that the most motivating rewards are often those that are unpredictable. This concept, known as “intermittent variable rewards,” suggests that once a link between behavior and reward is established, randomness can actually drive motivation more powerfully than predictable rewards. This principle has been shown in studies on animals and humans alike.

The Power of Intermittent Variable Rewards: Why Uncertainty Can Be Motivating

Behavioral studies, like those described by animal trainer Karen Pryor in Don’t Shoot the Dog!, illustrate the power of unpredictability. When training dolphins, Pryor found that rewarding every jump with a fish would lead to routine responses, with the dolphin eventually performing only minimally to receive the expected treat. However, when the reward was given on a random schedule—say, every few jumps rather than every single time—the dolphins would jump with vigor and excitement, constantly motivated by the possibility that this jump could be the one to earn a reward.

The same principle applies to humans. We’ve all experienced the thrill of checking our email or social media, not because we know there’s something rewarding waiting for us, but because there might be. This anticipation taps into our dopamine system, the part of the brain that motivates us to pursue rewards. Dopamine isn’t just about feeling good once we receive something we desire; it’s the anticipation, the “what if,” that sparks the most powerful release of dopamine, motivating us to keep going.

Dopamine and the Element of Surprise

When we open a present, the excitement we feel often stems from the unknown. If we already knew what was inside, our dopamine levels wouldn’t surge in the same way. Dopamine, it turns out, is not just about the reward itself but the surprise element. When a reward is unpredictable, the brain releases dopamine in anticipation, motivating us to repeat the behavior in the hope of getting a similar (or even better) reward.

This dynamic is why many apps and digital platforms use gamified rewards, like scratch cards or surprise cashbacks, to keep users engaged. This small element of uncertainty keeps users coming back, driven by the excitement of possibly receiving something valuable. In contrast, when rewards are predictable—like a fixed sales incentive—the brain’s response flattens. There’s no surprise, and therefore, no extra dopamine boost to drive motivation.

Why Sales Incentives Fail to Drive Lasting Behavior Change

If variable rewards are so effective, why do standard sales incentives often fall short? Part of the answer lies in how sales incentives are structured. Most sales incentives are highly predictable; employees know exactly what they’ll receive if they hit their targets. This predictability undermines the dopamine effect that might otherwise drive motivation. When a salesperson can calculate their monthly bonus down to the last dollar, there’s little room for the motivating power of “what if.”

Two key factors contribute to the limited effectiveness of traditional sales incentives:

1. The Gap Between Behavior and Reward: In behavioral science, timing is critical. For a reward to effectively reinforce a behavior, it should ideally follow the action closely. However, most sales incentives are awarded at the end of a month, a significant gap from the day-to-day behaviors that are meant to drive results. By the time the reward arrives, the connection between behavior and reward has faded, reducing its impact on future behavior.

2. Lack of Uncertainty: Predictable rewards yield predictable dopamine responses, which are generally lower than those triggered by uncertain or random rewards. Since dopamine spikes are associated with learning and motivation, a predictable reward structure—where employees know exactly what they’ll earn based on specific targets—doesn’t offer the same “dopamine hit” as an uncertain or variable reward system would. This lack of excitement limits the ability of the incentive to inspire ongoing motivation.

The Motivating Uncertainty Effect: Why Uncertain Rewards Drive Engagement

This phenomenon, known as the “motivating uncertainty effect,” explains why rewards that are not guaranteed can be so effective. When the outcome is uncertain, people are often willing to put in more effort, driven by the anticipation of a potential win. In contrast, when a reward is guaranteed, the brain stops learning from the experience, and dopamine levels stabilize, which limits motivation.

Understanding this effect sheds light on why traditional sales incentives may struggle to foster sustained engagement. If employees know exactly what they’ll receive at the end of the month, the thrill of the chase disappears. The reward becomes a transaction rather than a motivating force. In environments where success is tied to high energy, creativity, and resilience—qualities that thrive on motivation—this lack of excitement can undermine performance.

Rethinking Incentives: Learning from Behavioral Science

The insight here is powerful yet counterintuitive: the most effective rewards aren’t necessarily those that are guaranteed. Instead, they’re the ones that carry an element of surprise, driving motivation not through certainty but through the potential for a positive outcome. In the case of traditional sales incentives, predictability may actually be a barrier to maximizing performance, as the brain’s reward system thrives on anticipation, surprise, and novelty.

So, while predictability provides comfort, it may be unpredictability that truly drives engagement and performance.