Students who heard the same lecture on cats from two instructors scored equally well on a test, even though students with the better lecturer thought they'd learned more.
The study's results comport with a growing body of literature on the disconnection between what people think they have learned and what they actually did learn, Daniel M. Oppenheimer, an associate professor of marketing and psychology at the University of California at Los Angeles, said in an e-mail.
Intuition is not always accurate, added Mr. Oppenheimer, who has studied fluency and memory. "This has troubling implications for the usefulness of teaching evaluations and other common measures of teaching and course quality."
Ms. Carpenter cautioned that her results should not be interpreted to mean that lecture style is unimportant, or that bad lectures are acceptable. Instructors who teach in a fluent manner may also be more likely to organize their classes well and be attentive to students' questions, which would help students learn.
"I'd like to think," she said, "that there are things that instructors do that influence learning."