Chap 1: Attractive Things Work Better The visceral level is fast: it makes rapid judgments of what is good or bad, safe or dangerous, and sends appropriate signals to the muscles (the motor system) and alerts the rest of the brain.
Chap 2: The Multiple Faces of Emotion & Design
The three levels can be mapped to product characteristics like this:
Visceral design > Appearance
Behavioral design > The pleasure and effectiveness of use
Reflective design > Self-image, personal satisfaction, memories
Of the three levels, the reflective one is the most vulnerable to variability through culture, experience, education, and individual differences.