Research

The gentle science of persuasion, part seven: Unity

Shared identities have shaped human behavior since ancient times. In our final installment of this seven-part series, Emeritus Professor Robert Cialdini, the 'Godfather of Influence,' explores how the principle of unity makes us more likely to say 'yes' to those with whom we identify.

Molly Loonam

2025-04-22

Our communities thrive around shared identities — family units, religious groups, workplaces, neighborhoods — that strongly influence our behaviors. According to Robert Cialdini, those ties significantly shape our decisions.

Cialdini, professor emeritus of psychology and marketing, has dedicated his career to understanding the psychology of persuasion. Known globally as the "Godfather of Influence" for his contributions to the field, he has catalogued his research in over 240 peer-reviewed scientific papers, two bestselling books, "Influence: The Psychology of Persuasion" and "Pre-Suasion: A Revolutionary Way to Influence and Persuade," and founded the Cialdini Institute to bring the social behavioral science behind the six established principles of persuasion — liking, reciprocity, social proof, consistency, authority, and scarcity — to the public.

Then, in 2016, he surprised the business world by introducing a seventh principle — unity.

"I had always seen unity as an accelerator of other principles: If you have unity, then scarcity will work better, social proof will work better, and so on," Cialdini says.

Through his research, Cialdini realized that the principle of unity — sharing an identity, sense of partnership, or set of goals with someone else — can influence behavior on its own and, when applied ethically, influence people to say "yes."

Finding a shared identity

When Cialdini joined ASU's Department of Psychology in 1971, he took an unconventional approach to researching consumer behavior and the science of ethical influence by enrolling in hundreds of training programs run by marketers and salespeople. These experiences gave him a behind-the-scenes look at how "influence" professionals use the principles of persuasion to move products, drive business, and create long-lasting relationships.

To help business leaders understand the seven principles and how they can assist organizations in ethically achieving business goals and driving operational excellence, Cialdini broke the principles into three categories based on how they influence others:

1. Relationship building: Unity, liking, and reciprocity
2. Reducing uncertainty: Authority and social proof
3. Motivating action: Consistency and scarcity

The power of belonging

As relationship-building principles, unity can often be mistaken for liking. However, connecting with someone over shared surface-level similarities — movie genres, types of food, or a sports team — is different from the belonging someone feels with people they share a personal or social identity with.

Cialdini cites a recent study conducted on a college campus as an example of how unity differs from liking. In the study, a young woman dressed as a student stood in front of a United Way charity booth asking for donations. While she received some attention from passing students, the woman was significantly more likely to receive donations by adding a single phrase to her pitch: I'm a student here, too.

"It's not just being like you but being one of you," says Cialdini. "I may not even like you, but we belong in the same category."

Some identities are stronger than others, and Cialdini says familial bonds run so deep that they can transcend the principle of liking. For example, Cialdini's psychological research suggests that if a person were on a boat and had to choose between tossing a life preserver to a disliked sibling or beloved friend, they would be more likely to save their sibling.

"It's not liking — it's belonging. It's a shared identity, and that's the key difference between 'liking' and 'unity,'" says Cialdini.

While shared genes are one of the most powerful unifiers, research released this year found that there's another shared identity whose influence over us is growing.

"Political leanings overcome other things, and these days, it's making a difference in tribalizing us," says Cialdini.

The research showed that we increasingly favor those who share our politics while disfavoring those who don't. This makes us less likely to want them to share other identities with us, like being our coworkers or neighbors. These dual identities can negatively impact communities by making people less likely to want to accommodate and support those they perceive as having dual identities.

People are more likely to want to be connected to and influenced by those they share an identity with. But if you're struggling to find a unifying identity, Cialdini recommends remembering there is a category we all fit into: the human family.

In "Pre-suasion," Cialdini explored how people who live in culturally diverse neighborhoods and engage in diverse friendships are more likely to identify as a human family and less likely to show prejudice toward people whose ethnicities they do not identify with.

"Those smaller differences and designations exist, but there is also this larger one," he says. "If we think about our identities this way and try to raise it to consciousness in others, they will be more likely to want to partner with us."

Wired for 'we'

Evidence of the importance of unity can be traced back to ancient civilizations. As Cialdini describes in "Pre-suasion," there are records of cave people participating in dances, songs, and rituals, group bonding practices that unified tribe members. Cialdini says these synchronous practices can ignite feelings of unity so strong that they blur the lines between "we" and "I."

Unity may also be more deeply ingrained in our psyche than any of the other principles of persuasion.

A Belgian research study wanted to investigate what circumstances make people more helpful. Research participants were split into three groups: The first group was shown a set of photographs with various household items and a single person standing behind the item. The second was shown photographs of household items with two people standing behind the items. The third was shown photographs of household items with two people standing shoulder-to-shoulder behind the items, body language that signifies partnership.

After showing each focus group the photographs, the researchers stood up from their desks and pretended to drop the items they were holding on the floor. Participants in the first two groups were likely to offer help picking up the items 20% of the time. Participants in the third group, whose photographs showed people standing beside each other in unity, offered help 60% of the time.

While the study highlighted a deep-rooted awareness of unity, the most fascinating aspect was the participants' ages: They were all 18-month-old babies.

"That's how deeply the idea of togetherness — making a difference in who we partner with, favor, and assist — goes," says Cialdini.

Unity in the office

How can the principle of unity be applied to real-world business situations?

To get your colleagues' endorsement, Cialdini recommends asking for their advice, not their opinion, on the idea.

Why? Because if you ask for an opinion, you get a critic who focuses inside themselves, separating from you psychologically.

"If you change one word, you disarm that criticism," says Cialdini. "By asking for advice, you get a partner; and research shows that when people become unitized with you on a project in this way, you gain more favorable evaluations of your idea and more constructive input to it."

Over the past decade, marketing companies have adopted a unitizing tactic by requesting the co-creation of new generations of their offerings. Many brands ask their customers or clients to provide input on emerging products or services, which research shows leads to better evaluations and improved customer loyalty. To maximize these positive responses, the newest behavioral science indicates that, when asking for that input, they should ask for it as advice, not opinion or feedback.

Reminding someone of your shared identity is also applicable when asking others for favors or assistance. Cialdini reminisced on reaching out to a colleague for data to support a proposal he was preparing to submit on a tight deadline. The colleague was known for being difficult to work with and initially denied helping Cialdini with his request.

Cialdini reminded him that they had worked together for over a decade.

"He knew we were colleagues, but it wasn't top of consciousness," said Cialdini. "I had the data that afternoon."

The tactic worked because Cialdini drew on the truth of their shared identity. As with all principles of persuasion, unity must be used ethically so as not to take advantage of others or jeopardize the relationship.

"That's the whole thing about the influence process: Bringing levels of influence that are truly there in the situation," Cialdini said. "I wasn't deceiving him. I wasn't exaggerating. I wasn't counterfeiting our connection: I just pointed it out."

Ethical influence and digital unity

As the world becomes more digitized, there are even more opportunities for both ethical and unethical connections, both socially and between businesses and consumers.

"Can you logically and ethically use the terms 'we,' 'us,' and 'our' in your presentation?" asked Cialdini. "Because if people see themselves in the same situations, or have the same purposes or values as you do in that particular situation, you can arrange for them to see you as a 'we.' It's possible to do that online."

Bottom line:

• The principle of unity — one of the seven basic principles of persuasion — states that we are more likely to be persuaded to say "yes" when shared identities are at play.
• The idea of togetherness is deeply ingrained in us. Reminding someone of a shared identity can make people more willing to work with you and say "yes."
• Unity should be used ethically to avoid manipulating others, build a trusting, long-term relationship, and maintain credibility.

The series:

• Part One: Liking
• Part Two: Reciprocity
• Part Three: Social proof
• Part Four: Consistency
• Part Five: Authority
• Part Six: Scarcity

Advertising Marketing Faculty