In Search of a Look-Alike: Research Findings and Expectations
Outward likeness does not mean behavioral likeness.
Posted May 26, 2026 | Reviewed by Jessica Schrader
I became intrigued with look-alikes when one of my students told me about a website featuring photographs of people who look alike but are biologically unrelated to one another. It was created and is maintained by Canadian photographer Francois Brunelle. Ironically, Brunelle titled his work the “I’m Not a Look-Alike Project.”
My interest in these curious pairs of people comes from my research with twins. Twin studies show that genetic differences among people explain about 50% of the personality differences between them. This finding is consistent with an important result of a personality analysis done by the Minnesota Study of Twins Reared Apart (MISTRA), a project with which I was associated between 1982-1991. The MISTRA researchers found that the personalities of identical twins reared apart are as similar as the personalities of identical twins reared together. This shows that if we resemble our family members, it is because of our shared genes, not our shared environments.
A challenge raised against reared-together twin studies is that people treat identical twins the same way based on their appearance—and that this treatment, not their genes, explains their behavioral resemblance. I realized that I could test this idea using unrelated look-alikes. Two outcomes were possible: (1) Look-alikes would be as similar as identical twins, supporting the view that treatment largely shapes personality, or (2) look-alikes’ personalities would be different, supporting the idea that people respond to identical twins the same way because they evoke the same treatment due to their shared genes. Brunelle allowed me access to some of his sets, and I found others on my own. Most recently, I had an amazing experience that offers insights into these findings.
Case Study: Mother and Daughter Look-Alikes
A few months ago, I attended a performance of the musical Hairspray . The lead actress (who played Tracy Turnblad) was marvelous and memorable. I went up to her after the play finished since I saw her talking with several others who had attended the show. However, I was astonished to discover that I had approached her mother, not her twin! They looked so much alike and, of course, are genetically related—the daughter inherited exactly 50% of her genes from her mother. I knew I could not use them in my look-alike study—but they were ideal for my research into the challenges raised by possible human reproductive cloning (HRC).
HRC was headline news after the 1996 cloning of Dolly, the Scottish lamb. Most people (scientists and the public) worried that if this procedure eventually proved safe and cost-effective, it would destroy families, family relationships, and individual identity . However, critics argued from emotion , not from scientific sources. In response to the controversy, I authored a paper stressing that the ideal human model for evaluating these challenges was being ignored—identical twins. Over the years, I realized that other human models were also available and informative, e.g., look-alike parent-child pairs. The mother and daughter I met at the play were perfect for this quest and agreed to an interview with me. Here are selected excerpts from that interview:
(Nancy Segal NS): Do people confuse you the way I did if you're not together?
(Daughter D): Yes, mostly at shows or in situations where they see one or the other beforehand. Usually, it's seeing me before my mom, but never my mom before me.
(Mother M): These three guys came up to me after [a different] show and they were like, "Oh my God! You were amazing! We just couldn't keep our eyes off of you." And I looked at them and I said, “Why, thank you." It went like that.
NS: How do you feel when people confuse you?
D: It's happened since I was little, so it's not really confusing me—I've known my whole life that we look exactly alike... I think I just feel neutral about it. I mean, like I said, because it's such a normal thing.
NS: How do you [mother] feel when people confuse you?
M: It makes me feel happy because I guess I'm not aging as fast as I think I am. You know, because she's still 25 and I'm 52. You know, it just makes me happy.
NS: How would you describe your relationship with your daughter?
M: I follow her to her auditions—some people may think that I'm a stalker , you know, but I'm supportive, you know? I mean, we've always had a really great relationship...
NS: How would you describe your relationship with your mother?
D: We've always been really close. We've had a good relationship. As I got older, I very much like connected more to her side [than my dad’s side] ... I'm just completely thankful that I'm able to have her as a mom.
Personality Differences and Family Resemblance
Mother and daughter listed more personality differences than similarities—for example, the daughter is an actress, and the mother is a personal assistant. Again, parents and children share 50% of their genes, whereas identical twins share 100%, so parent-child pairs are expected to show relatively less personality resemblance. Most significantly, the extraordinary physical similarity of mother and daughter, despite their twenty-five-year age difference, has not interfered with their close relationship—and looking alike does not mean acting alike. This response has been voiced by other look-alike pairs and should help to quiet the identity and stigmatization concerns over possible HRC.
One more word: people looking for look-alikes online or elsewhere will be disappointed if they expect to be behaviorally similar and develop a close relationship—very few look-alike pairs I studied became close. We need to think about the insightful words of my late colleague, David Rowe, who reminded us that personality is in the brain, not in the face.
More expansive treatments of HRC are available in the Review of General Psychology and forthcoming in Twin Research and Human Genetics .
Segal, N.L. (2025). Human reproductive cloning: Possible psychological consequences. Review of General Psychology, 29 (3), 325-336.
Segal, N.L. Twins and look-alikes: Perspectives on human reproductive cloning. Twin Research and Human Genetics (2026, in press).
Rowe, D.C. (1994). The limits of family influence: Genes, experiences, and behavior . NY: Guilford Press
Segal, N.L., Hernandez, B., Graham, J.L., & Ettinger, U. (2018). Pairs of genetically unrelated look-alikes: Further tests of personality resemblance and social affiliation. Human Nature, 29(4), 402-417.
Share this post Facebook Bluesky Linkedin Email
There was a problem adding your email address. Please try again.
By submitting your information you agree to the Psychology Today Terms & Conditions and Privacy Policy
Nancy L. Segal, Ph.D. , is a professor of psychology and the Director of the Twin Studies Center, at California State University, Fullerton.
Get the help you need from a therapist near you–a FREE service from Psychology Today.
This article is part of the Bringwise Psychology Journal — daily insights on human behavior, mental health, and personal growth.