William Shakespeare once said, “So dear I love him that with him, all deaths I could endure. Without him, live no life.”

Love is an enduring characteristic in many people’s lives, but it is a complex process that has many ups and downs. Professor of psychology Dr. Carl Charnetski said there are various ways for two people to become attracted to one another. One way is by facial symmetry.

“The more symmetric the face is, the more attractive that person is,” Charnetski said.

Charnetski said a study done in Switzerland showed that scent plays a role in attraction. Women were told to smell men’s T-shirts and rate the attraction based on the particular scent of the T-shirt. The study found that women were more attracted to men who had similar bacteria from the perspiration on the shirts as they had.

“Women were more attracted to men that had similar bacteria or a similar immune system as their own,” Charnetski said. “The bacteria that were left over were not killed by the immune system.”

In a study published in Charnetski’s 2001 book, “Feeling Good is Good for You: How Pleasure can Boost Your Immune System and Lengthen Your Life (http://books.google.com/books/about/Feeling_Good_Is_Good_for_You.html?id=APS9aS6E4HMC),” Charnetski found that love can boost one’s immune system. In the study, the most important aspects of love are intimacy, passion and commitment as cited by psychologist Robert Sternberg. Sternberg created the Triangular Love Scale to measure these aspects, which Charnetski used in his study.

“I found that people who are very much in love and engaged in a moderate amount of sexual activity had higher levels of the antibody Immunoglobulin A than couples that engaged in less or more sexual activity,” Charnetski said.

Immunoglobulin A is one of the major antibodies critical to disease prevention and resolution of diseases. He said by measuring the variables of intimacy, passion and commitment, scientists can determine how in love people are. In terms of how people fall are attracted to each other, there are many factors that are primarily emotional but some physiological.

“First impressions that later develop into lasting relationships can often begin with what is considered to be attractive and the physical first impression does matter,” says professor of communication studies Dr. Jane Elmes Crahall, who teaches a course in interpersonal communication that touches on romantic relationships. Elmes-Crahall says shared activities are what bond people together.

“Most of what attracts people has to go beyond the physical exterior, it has to include shared goals, values, similar communication styles and interests,” Elmes-Crahall said.

She says the idea of shared values usually bonds couples together and that it takes hard work, forgiveness and negotiation to keep a relationship together. When people first get together, there is a certain length of time for people to become comfortable with one another. The words people say also have different meanings, which can become sacred or hurtful.

“We take it to the point where words hurt and then there are words that are legally binding in romantic relationships such as marriage vows,” Elmes-Crahall said.

Overall, romance depends on whether the content of the relationship balances with the relationship.