This was sloppy on my part. I meant "interact" in a statistical sense - https://en.wikipedia.org/wiki/Interaction_(statistics) https://en.wikipedia.org/wiki/Int

This was sloppy on my part. I meant "interact" in a statistical sense - https://en.wikipedia.org/wiki/Interaction_(statistics) https://en.wikipedia.org/wiki/Interaction_(statistics). I'm not a medical expert, so I'm a bit inconsistent in terminology, but have ran my fair share of (cognitive) psychological experiments (and developed methods for them), which rely on similar logic as to that of double-blind testing.