Even in humans, negative stimuli carries more weight than positive, in the general case.

Without reading it yet, my first thought would be to test a general ratio, something similar to human interpersonal relationship ratios like 30% negative to mostly positive, and positive are targeted, such as reinforcement not just for the good job, but reinforcement for the improvement.

And ensure the negative is targeted, such that you point out tendencies to be avoided rather than just specific instances.

Of course, most human interaction online has none of this, so, would be hard to replicate.