With Valentine’s Day around the corner, relationships are on everyone’s mind. For Prof. Elizabeth Riley, psychology, it’s something that she discusses and studies daily through her course, HD 3620: “Human Bonding.”
The iconic Human Bonding course began with Prof. Cindy Hazan, psychology, nearly forty years ago. It started as a small 25 student class, eventually becoming one of the most popular courses on campus, taken by over 600 students each spring.
One former student said on Rate My Professor, "You will walk out of this class with knowledge that you will use for the rest of your life. If you're in a relationship or ever plan on being in one, this class is incredibly insightful.”
Another student wrote, “I swear [Hazan] is the reason I now have a boyfriend just after taking her class."
Hazan retired earlier this January, and Riley felt “greatly honored” when the Human Bonding course was offered for her to continue starting Spring 2026.
“It was a beautiful opportunity to get a chance to participate in that and to share possibly the most important thing about life,” Riley told The Sun. “I mean, there are a lot of things that are really important, but who your friends are, who you fall in love with — it's about as important as it could possibly get.”
Riley is a research associate and lecturer of psychology studying neuromodulatory systems, the neuron circuits that control brain activity and behavior. Her research focuses on norepinephrine and its relation to cognitive aging, which can be prevented by human relationships.
Norepinephrine is a neurotransmitter — a chemical messenger that transmits signals through the body — that regulates the “fight-or-flight” response and is a critical part of the nervous system. While the nervous system is an important system for survival and cognitive function, Riley explained that it accumulates Alzheimer's-related damage in the brain before any other system.
“When you study the correlates of neurodegeneration, you start asking yourself what protects against neurodegeneration,” Riley said. “And there are a lot of protective factors, but one of the very strongest ones is human relationships.”
Riley’s Human Bonding course covers various topics relating to social relationships, including why humans seek relationships and what factors make a relationship strong or weak.
Riley explained that humans, like other social animals, form pair bonds, strong social and emotional attachments associated with mating and parental care. Evolutionarily, psychologists hypothesize that pair bonds allow for the better survival of human offspring.
“This is a theory, of course … but this is the idea that pair bonding is fundamentally a mechanism that allows people to provide better care for offspring,” Riley explained.
Surprisingly, in psychology, pair bonding is much different from standard romantic relationships seen in society. Riley explained that a true pair bond relationship takes 18 months to form, on average. However, this timeline can vary.
“I think there's some research that suggests that if you live with your partner, the timeline is a little bit compressed, and more frequent or earlier sex also compresses that timeline,” Riley said. “Being long-distance can increase the amount of time that it takes to form the bond.”
Riley noted that while sex can compress the timeline of forming a pair bond, this is not always the case. In today’s generation, people often engage in sexual encounters without having a clear commitment, dubbed “situationships.” Hookup culture is also a prevalent social norm on college campuses, which accepts uncommitted sexual encounters without emotional bonding.
“People have sexual encounters that have nothing to do with the pair bonding system,” Riley noted. And sexual encounters are not the only thing that helps create an actual bond, according to her — she explained that other activities, such as cuddling or more face-to-face time, can raise the probability of creating a pair bond even higher.
There are scientific principles about communication that make a pair bond healthy and lasting, which are covered in Riley’s Human Bonding course. One concept she discussed was the “Four Horsemen of the Apocalypse,” described by John Gottman, a professor at the University of Washington who studies how communication can prevent issues in pair bonding.
This metaphor describes the four communication styles, or “horsemen,” that can predict the end of a relationship: criticism, contempt, defensiveness and stonewalling.
Criticism means attacking your partner’s character, often using statements such as “you always” or “you never.” For example, “You told me you would pick me up from the Eng Quad after class today! You always forget about me. You didn’t forget, you’re just selfish and only think about yourself!”
Contempt regards treating partners with superiority, disgust, and disrespect to make them feel small. For example, “You’re so pathetic! How did you even manage to fail microeconomics — I can’t believe I’m dating an idiot.”
One study showed that couples who exhibit contemptuous behavior are more likely to suffer from infectious illnesses such as colds due to having weakened immune systems.
Defensiveness refers to acting defensively and redirecting the blame to one’s partner rather than accepting responsibility. For example, “You’re exaggerating the situation. I didn’t skip your concert, I had to do something with my brothers! I try so hard to make you happy, but you’re always picking on me.”
Stonewalling means shutting down and not responding to one’s partner instead of confronting issues. An example would be saying “Fine, whatever,” before walking away to avoid further conversation.
And while this course covers various ways to build or strengthen a pair bond, it can also apply to people who aren’t in romantic relationships.
“It's useful for everybody,” Riley said. “It never hurts to know more about the most important decisions that we will make in our whole lives. It’s about how deeply and completely and profoundly [relationships] affect everything about us, how our bodies work, how our minds work, how our lives go, whether we're healthy into our old age, the diseases we get — all of that is affected by our relationships.”
Current students in this course also noted Human Bonding as a course applicable outside of class.
“As a Dyson major, I wanted to take a class that focuses more on humanity and helps me understand how our brains work and what makes a genuine connection,” said Sooa Kim ’28. “I would say it’s one of the most interesting classes I’ve taken at Cornell, and it’s incredibly relevant to my life. Taking this class gave me a deeper understanding of my behavior in different situations.”
Erin Park ‘28 also noted that learning the science behind human relationships and behaviors drew her to the course.
To people who may not be in a relationship at the moment, rest assured, romantic relationships aren’t everything.
Riley added, “And is it more important than having friends? No, I think there are plenty of ways to be happy.”
Andrea Kim is a Sun Contributor and member of the Class of 2028. She can be reached at ack247@cornell.edu.
