Quick Definition: The unconscious and automatic changes in attraction that women experience based on their physical position in relation to the PUA. (Otherwise known as “locking in” in positive biofeedback loops.)
Bio-feedback is a term coined by Mystery to refer to the way that the attraction level of a woman can change based on her physical position. Women are very in-tune to their surroundings and the body language of those around them. Thus, their buying temperature can change based on the body positions of others in the room.
For example, when a group of girls are leaning towards a man, it can trigger attraction in other women in the room, based on preselection. The women who are leaning in will also experience Bio-feedback, and their attraction levels rise based on the power shift that happens when they lean in, which they then backwards rationalize as attraction. This is why locking-in is important, as the physical position of a PUA in a set can literally create attraction in the women around him.