A team of researchers with members from a large number of institutions in Germany has conducted a study that has revealed more about the way interpersonal attraction works in the brain. In their paper published in Proceedings of the National Academy of Sciences, the group describes two experiments they conducted with volunteers, their results and what they believe was revealed about the nature of the mechanism of attraction between people.
My comment: The financial support for this team should be examined in the light of what we published 15 years ago in our award-winning review.
The ‘affective primacy hypothesis’  asserts that positive and negative affective reactions can be evoked with minimal stimulus input and virtually no cognitive processing. Olfactory signals seem to induce emotional reactions whether or not a chemical stimulus is consciously perceived. We theorize that the importance of human non-verbal signals is based upon information processing, which occurs in the limbic system, and without any cognitive (cortical) assessment. Affect thus does not require conscious interpretation of signal content. Underlying this fact is that affect dominates social interaction and it is the major currency in social interactions . Affective reactions can occur without extensive perceptual and cognitive encoding. They are made with greater confidence than cognitive judgments, and can be made sooner [5, 7]. Olfactory input from the social environment is well adapted to fit such assertions. For example, chemical cues allow humans to select for, and to mate for, traits of reproductive fitness that cannot be assessed simply from visual cues. — ”