Placebo. It's the interaction between our mind and our immune system. That immune system is built on our genome, but its beauty is that it learns from experience. My allopathic doctor believes much of the heavy lifting in modern medicine's treatment regimes is done by the placebo effect.
Likewise our visual aesthetic of what is good is determined by a mix of neurochemical response built on our genome, the interplay of novelty and familiarity, and the entire corpus of our visual experience.
So placebo is a rich metaphor for response to art and not a slight. Artists combine, by design or subconscious genius, visual and conceptual ideas that activate their own, and viewers, placebo effect. That's the idea of Maggie Casey's show Placebo. Casey was one of the organizers of the Little Field and Appendix spaces in garages off Alberta. She is now at RISD working on her MFA.
Recommended. At the 12128 Labrador Project http://www.12128boatspace.com/ It's moored by Fred's Marina 12900 NW Marina Way, Portland. Map More detailed directions, don't get lost, on the website. 7PM-10 Free