Quantify

Complex as it may be, attraction can be broken down into three primary elements, each with two main contributing factors.

1) Nonverbal Emotional - this is the desire to be in someone's presence regardless of what you are doing. This element is the most difficult to define and also the most crucial.

Contributing factors include: body language and facial expressions

2) Verbal Emotional - this is the desire to speak and listen and be listened to. This is arguably the most "human" of the elements.

Contributing factors include: charm and empathy.

3) Physical - this is the desire for sex or other physical contact (such as kissing, hugging, cuddling, etc). This is the most basic/animalistic of the elements.

Contributing factors include: pheromones and the evolutionary need to reproduce

Note: I am well aware that attraction is impossible to accurately quantify, so this should not be taken too seriously. I simply found it interesting to write.