Whether they are playing on two pianos or one, Christina and Michelle Naughton are so in sync with each other that it's hard to distinguish one sister from the other.
That is true offstage as well. In a recent phone interview from their home in New York City, the 28-year-old twins talked rapidly without identifying - unless asked - which of them was speaking.
What if the wrong sister is quoted?
"Oh, it doesn't matter," said one.
"We don't mind - however you want to do it," said the other.
At the La Jolla Music Society's SummerFest 2017, the pair will appear in the opening concert, "Fiddles vs. Pianos," on Friday and "From Prague With Love" the next night. Preceding Saturday's concert, the Naughtons will be interviewed by SummerFest's scholar-in-residence, Eric Bromberger.
"From Prague With Love" will feature the sisters performing Chopin's Rondo for Two Pianos in C Major, Op. 73, and Witold Lutos?awski's Variations on Theme of Paganini for Two Pianos.
"The pieces provide a nice contrast," Michelle said. "They are kind of like old friends. We've played both many times, but not necessarily together or in the order in this program. It creates spontaneity."
"Putting it in a different repertoire brings an old piece to life," Christina noted. "It's like a meal, how foods complement each other."
The performances will take place at the University of California San Diego's Conrad Prebys Concert Hall. The opening program - a friendly "competition" between violinists and pianists - will feature the sisters performing Mendelssohn's Andante et Allegro Brillant for Piano Four-Hands, Op. 92. Their empathetic dynamic will be on full display as they share one piano.
For Tuesday's "In the Heart of Hungary" concert, Michelle will perform Bartók's Falun, Village Scenes with Russian soprano Lyubov Petrova. Michelle is playing that evening because it's "her turn" - the Naughtons rotate solo performances.
Growing up in Madison, Wis., the twins began piano lessons at the age of 4. Their mother, who had studied piano as a teen, taught them individually. She started with two 10-minute lessons a day. One-on-one time with their mom, Christina and Michelle agreed - with an added bonus of candy - was a definite motivator.
They were solo pianists until high school, when the siblings were asked to perform together at a dedication of a concert piano. It felt so "magical" that they dedicated themselves to playing as a duo.
How do they decide who plays what parts?
"For two pianos, we draw straws," Michelle said. "For four-hand pieces, we have it set."
Christina elaborated: "I like playing the bottom because it sets the emotional mood of the piece."
SummerFest presents an unusual situation for the constantly touring sisters. They'll be staying put for a few days, enabling them to spend time with other musicians.
"A lot of artists will be there," said Christina, the eldest of the twins by eight minutes. "Sometimes being a musician is lonely, always on the road. Michelle and I have each other, but it's still isolating."
Michelle concurred, adding: "It's powerful to come together with great musicians in a beautiful place and stay for a while. You create bonds in those situations. We're really looking forward to that."
The sisters revel in playing onstage for audiences. So much so that, in making their 2016 album "Visions," they ended up using just a few of the pieces they had recorded in the studio.
"The beauty of every live performance is that there's risk," one sister said. "It's special."
"You play differently with an audience," the other sister said. " 'Visions' turned out to be 90 percent live. We did not expect that. Something about the energy of the audience adds so much to the performance."
SummerFest 2017: "Fiddles vs. Pianos"
When: 8 p.m. Friday, Aug. 4
SummerFest 2017: "From Prague with Love," featuring Christina and Michelle Naughton
When: 8 p.m., Saturday, Aug. 5; 7 p.m., Prelude with the Naughton sisters
Summerfest 2017: "In the Heart of Hungary"
When: 8 p.m., Tuesday, Aug. 8
Each of these concerts is preceded by a 7 p.m. "Prelude," an artist interview or lecture, hosted by SummerFest's scholar-in-residence, Eric Bromberger.
Where: UC San Diego's Conrad Prebys Concert Hall, 9500 Gilman Drive, La Jolla.
Phone: (858) 459-3728
Wood is a freelance writer.