"demotivating". Good word.

Good word describing a bad phenomenon.

What our brain does when we are criticized:

At any given time, brains are subconsciously scanning the world around us for dangers to defend against—ready to launch a fight, flight, or freeze response that will protect us from predators or poisons. But the brain doesn’t just guard us against physical threats.

Research has found that it also goes on the defensive in response to things that threaten to undermine our social standing and safety, including interactions that make us feel even mildly rejected or incompetent. Since even being glanced at askance by a stranger can be enough to trigger our defenses, you can bet that receiving critical feedback is pretty likely to spark a fight, flight, or freeze response.

That matters because when our brains are in defensive mode, studies have shown that there’s reduced activity in the brain’s prefrontal cortex. That’s where our most sophisticated mental machinery generally lives: the neural systems responsible for self-control, reasoning, and forethought.

So it’s no wonder we don’t always respond graciously to feedback; it’s quite likely that our most thoughtful, attentive, flexible selves are somewhat offline. In fact, it’s possible that we’re not even properly listening. 

The better way to give feedback:

Thankfully, this understanding of the brain reveals a little routine that we can all use to ensure that helpful feedback lands as it’s intended. It goes like this:

1. Tell the other person: "What I like about this is . . ." Give meaningful, specific examples of what you like, and explain why you like them. Aim for as many concrete positive points as you can. Don’t rush.
2. Then say: "What would make me like it even more is . . ."

The goal in the first of these two steps is to be at least as tangible and forthcoming in your praise as you are in your criticism—not just saying "it’s great," but what specifically is "great" about it. (Matt might've said, "I really liked the way you pulled in survey data to support your argument, for example in the section on page two. It tells a great story and sticks in the reader’s mind.") These sorts of details matter; they make it far more likely that the person properly absorbs the fact that you value aspects of whatever they’ve said or done.

Taken together, these two sentences can greatly improve your chances of keeping the other person’s brain out of defensive mode as you give them feedback, making it far more likely that you’ll have a productive and good-natured conversation. This way, they can actually process your feedback intelligently and decide whether to act on it.Then, when you introduce your suggestion for improvement with the phrase, "What would make me like it even more," you’re framing your comment as an idea that—if explored—could take the other person from good to great, rather than something they were really dumb not to have done. You’re still making the point you need to make, but it feels much less threatening to your listener's competence and self-respect than the usual, "How about doing this differently?"

For what it’s worth, this "What I like . . ." feedback model can help you as the feedback-giver, too, because being forced to find something you like—however hard it is to uncover it—often reveals something useful that you might've missed had you led with your criticisms.

Finally, if you’re the one habitually receiving feedback rather than giving it, you can do what I eventually did with Matt, which is to simply ask him to give me brain-friendly feedback. I didn’t have to use any jargon, either. "First of all, can you tell me exactly what you liked and why?" I said. "It’s important for me to learn from that. I want to know what I should keep doing, or do more of. Then you can tell me what would make you like it even more!" The result? A fine, fistfight-free working relationship—and a finished book to boot.