John Jacobson, supervisor of the neurobiology lab at Salk, said he asked Holmes to create several online demonstrations of the lab's work on temporal perceptions. Jacobson said he repeatedly tried to explain to Holmes exactly how to do the computer programming, but Holmes kept insisting on a different approach -- one that did not work.
"He was really, oddly, stubborn," Jacobson said.
Jacobson said he made a point of sitting down to lunch with Holmes at least a half-dozen times, trying to draw him out and encourage him, but found it impossible to make conversation. "He was extremely shy," he said. "It was really hard for him to say anything. You had to ask yes or no questions."
At the end of the summer, Holmes had to make a presentation to his fellow interns about the work. A video, widely circulated online since the shooting, shows him smiling shyly and talking with some confidence.
But Jacobson said he spent an entire day going over that presentation with Holmes and never got the sense that he understood any of the basic science.
"He was very undistinguished," Jacobson said.
After the internship ended, Jacobson said he emailed Holmes to ask if he wanted to try to finish up the project. Holmes never responded, he said.
Holmes did succeed academically as an undergraduate at the University of California at Riverside, graduating with honors in a neuroscience program that is considered very demanding. He then won a spot at the prestigious neuroscience doctoral program at the University of Colorado's Anschutz Medical Campus.