Ayelet Fishbach, Tal Eyal, and Stacey R. Finkelstein have written an interesting research paper titled, "How Positive and Negative Feedback Motivate Goal Pursuit." They examined the usefulness of positive and negative feedback. They conclude that timing matters. Moreover, it matters whether you are evaluating your commitment to a particular pursuit (positive feedback more helpful), or whether you are evaluating your progress toward a goal (negative feedback more helpful). The authors explain:
We propose that whether people wish to evaluate their commitment or pace of pursuing a goal influences whether positive or negative feedback is more effective. Our theory further predicts that the question people ask themselves (‘am I committed?’ versus ‘am I making sufficient progress?’) shifts over the course of pursuing a goal. People often start by evaluating commitment and then shift to monitoring progress as they gain experience or expertise in a goal domain. They make this shift because novices feel uncertain about their level of commitment, whereas experts are already committed and wish to monitor their rate of progress. One consequence of this shift is that novices should increase their efforts in response to positive feedback on their successes, and experts should increase their efforts in response to negative feedback on their lack of successes.
The authors describe a series of studies on this topic. As an example, they examined student choice of instructors for French classes. They found that beginner students preferred instructors who offered positive feedback. Advanced students preferred instructors who offered more negative feedback.
What's the lesson here? If someone is just starting out on a challenging new task, they may want and need encouragement. They could use more positive reinforcement than negative feedback. However, as they begin to move toward mastery of that task, they need more negative feedback so that they can continue to improve.