Marilu Henner can immediately remember everything she did Feb. 24, 1977. It was a Thursday. She was living in New York. She had just come back from a trip to shoot a TV pilot, and that day she was auditioning for a movie role. She can remember what she was wearing and the fight she had with her boyfriend at the time.

For Henner there was nothing particularly special about that day. Charan Ranganath, a UC Davis psychologist, chose the date to demonstrate Henner’s memory for his students during his PSC 130: Human Memory class in Young Hall 49 years later.

“All these things just start to fill in. So that's how my brain works.”

Henner, the actress perhaps best-known for her role on the classic TV show Taxi, spent the afternoon of February 24 on campus while filming a documentary with Ranganath, a professor of psychology and a leading expert on memory. Henner is one of fewer than 70 people worldwide who have been identified to have highly superior autobiographical memory, or HSAM.

“Everything is available when you have a good memory,” said Henner.

Always had a great memory

Henner said she always had a great memory but didn’t figure out just how unusual and special it was until she took a standardized test in the third grade that included the question of how many pencils are in a score. 

She didn’t know, but then she remembered learning about the Civil War and Abraham Lincoln’s Gettysburg Address, which begins, “Four score and seven years ago, our fathers brought forth…”

She began working out the math and soon knew the answer: a score is 20.

“Because I had this unusual memory, I started to make these connections,” said Henner. “It’s an amazing feeling to realize that everything is connected to everything.”

As a student at the University of Chicago, Henner became well-known among her peers for her memory. But it was well after her success in entertainment that she learned just how unusual her memory was. 

Friend and journalist Leslie Stahl invited Henner to lunch and told her about Jill Price, who had been undergoing testing by researchers for her own powerful memory. Price would be the first person to be identified with HSAM, and Stahl was working on a possible story about the phenomenon. 

At that lunch, Stahl asked Henner about events throughout her life. When a producer with Stahl told Henner the date of her wedding, Henner asked why she got married on a Monday. Stahl was convinced Henner had HSAM.

While Stahl ultimately did not do a story on Price, years later she asked Henner to get tested. By that point only five people worldwide had been identified to have HSAM. 

Henner worked with researchers at UC Irvine who asked her a battery of hundreds of questions about sequences of numbers, movie plot points and boxes of items. They took 300 measurements of Henner’s brain and found nine areas that are 10 times larger than for the average person. It was clear she had HSAM.

“There was finally a name for something I’ve known I had for my entire life,” said Henner.

Documenting a real-life superpower

Filmmaker Morgan Pehme was reading up for a new documentary film about Henner’s memory he was making with co-director Daniel DiMauro when they found Ranganath’s best-selling book Why We Remember. 

In the book, Ranganath combines the latest memory research, some of it from his Dynamic Memory Lab at UC Davis, with his own personal experiences to share the science of how memory actually works. It explains how big a role memory plays in our sense of who we are, why we hold onto old memories throughout our lives and also why we form stronger bonds with people who share memories with us.

“Charan’s book really stood out,” said Pehme. “It’s so accessible and humanistic.”

Pehme reached out, and in in January he filmed a conversation in Davis between Ranganath and Henner to try and understand how her incredible memory relates to who she is as a person. 

“She is just incredibly positive,” said Ranganath. “You don't have to talk to her for more than five minutes to get a sense of just the force of her personality.”

That day in January, Ranganath and Henner both thought their conversation could easily have continued. Ranganath also thought it would be fun for students to join. 

“I said, ‘Well, if you do it on my birthday, then you can come over to my house afterward for dinner,’” said Ranganath. “And that’s what we arranged to do.”

The film will include Henner in conversation with people she has known for most of her life. This includes cast-mates from Taxi Christopher Lloyd and Judd Hirsch, as well as Jay Leno and Leslie Stahl.

“The conversations that we have with all the people in Marilu’s orbit, and then experts like Charan, are ultimately a way for us to inquire about the role of memory in our own lives,” said Pehme.

Students get answers, advice

During class, Henner moved back and forth across the room, even once nearly stumbling against the camera operator who followed her. She wanted to see everyone’s faces while she spoke.

“Can you see I love being here with you guys?” she said. “I’m so happy.”

Just a week ago, she was in New York to perform in a theater production of Pen Pals, one of more than 32 projects across film, theater and voiceovers she has done since 2020. Henner was also recently on the Today Show talking about her memory and this documentary film. She also mentioned she was coming to visit UC Davis.

“Everybody wants to have a better memory,” said Henner. “It’s so much better if you have a better autobiographical memory because it’s using your own life.”

Students also had a lot of questions.

How has her access to memory influenced her acting?

She used to be able to read a script once or twice and have it down, but that didn’t help her understand the character’s intention in saying those words. 

Does she remember all the bad memories, too?

While everyone will remember the highs and lows in life, Henner also remembers the mundane events throughout her life. Her siblings will sometimes ask her to walk them through a whole week from their childhood to relive those simple memories.

What day of the week was Sept. 27, 2004?

“That was a Monday,” she answered immediately. “And that’s how fast it works. It’s crazy.”

Henner also offered some life advice.

Learn to love the food that loves you.

Motion is the lotion, so get out and move.

Don’t make your phone your memory, because you might lose it.

Don’t be afraid to get help.

Don’t be afraid to be different.

Use your memory to bring the past to the present and let it inform a better future.

“You wake up, you live your life, you turn off the light and go to sleep,” she said. “Developing a better autobiographical memory is the strongest defense against meaninglessness that we have. Because then our lives count for something.”