“How on earth are you ever going to explain in terms of chemistry and physics so important a biological phenomenon as first love” ~ Albert Einstein
• Lust exposes people to others
• romantic attraction encourages people to focus their energy on mating; and
• attachment involves tolerating the spouse (or indeed the child) long enough to rear a child into infancy.
Lust is the initial passionate sexual desire that promotes mating, and involves the increased release of chemicals such as testosterone and estrogen. These effects rarely last more than a few weeks or months.
Attraction is the more individualized and romantic desire for a specific candidate for mating, which develops out of lust as commitment to an individual mate forms.
As people fall in love, the brain consistently releases a certain set of chemicals, including pheromones, dopamine, norepinephrine and serotonin, which act in a manner similar to amphetamines, stimulating the brain's pleasure centre and leading to side effects such as increased heart rate, loss of appetite and sleep, and an intense feeling of excitement.
Since the lust and attraction stages are both considered temporary, a third stage is needed to account for long-term relationships.
Attachment is the bonding that promotes relationships lasting for many years and even decades. Attachment is generally based on commitments such as marriage and children, or on mutual friendship based on things like shared interests. It has been linked to higher levels of the chemicals oxytocin and vasopressin to a greater degree than short-term relationships have.
~ Wikipedia
