Psychological Insight - High Int - Bonus to songs based on INT. This one is what I wanted.
Erode Confidence - Auto-demoralize during combat. I also wanted this.

Psychological Insight gives a very good bonus to your songs. Even obvious on a wood-elf where 23-int is not much higher than 22-cur. On a 22-int/18-chr char should have a much greater effect. Although I had PERFECTED most of my songs, they still had not much effect. My wood-elf had MUCH better results.