I suspect you already know the answer. You are looking for an authority to back you up. My research and experience put me squarely in your corner. Children need encouragement like plants need the sun. You are correct, that overpraise can spoil kids. But encouragement while they are learning and acknowledgment of growing skills have been well-documented as essential to good teaching. Catching kids doing right is far more powerful and valuable to their developing sense of appropriate behavior than catching them doing wrong.
Kids also need affection and nonverbal gestures of approval in order to feel like they matter. Even monkeys provide their young with hugs and stroking and grooming. When deprived of physical affection, baby monkeys fail to thrive. Children are no different. If they don’t get enough physical attention, warmth and bonding, they are at risk of developing Reactive Attachment Disorder.
I’m concerned that the two of you are in this debate at all. I doubt very much that words from an “expert” will persuade your partner to do things differently. We need to understand why he worries that being warm and loving and encouraging will be detrimental to the children. Was he deprived of loving care as a child? Does seeing the warmth you offer to children pick at an old emotional wound? Does he think that there isn’t enough love available for him if you attend to the children’s emotional needs? Has something happened that has put you on opposite sides rather on the same team? Getting to the bottom of the issue is at least as important as deciding who is “right”.
If you find that the two of you can’t talk reasonably and sensitively about these issues, please consider seeing a therapist to help resolve the conflict. The children deserve loving parents. The two of you deserve to be out of the fight so you can take good care of the children you love.
I wish you well.