Zoos and aquariums have recognized the importance of integrating living collections with personally delivered interpretation. One way for zoos to accomplish this is by conducting public animal training sessions accompanied by personal interpretation. Many institutions offer these types of interactions, but the term “interpretation” is used loosely and without clear definition. This exploratory study compared knowledge gain of individual students in three different fifth grade school groups visiting the Potter Park Zoo in Lansing, Michigan. Each group observed an animal training session, with two groups receiving two types of presentations and one group serving as a control group. Although hearing the same facts, the two treatment groups received different program types: an interpretive presentation and a fact-only presentation. The third group viewed the training session but received no presentation. Results showed that individuals who received the interpretive presentation retained more information immediately after the training session than individuals in either of the other two groups. This exploratory study suggests that using an interpretive presentation style is more effective in producing knowledge gain than fact-only presentations in informal learning environments such as zoos and aquariums. Zoo Biol 28:488–495, 2009. © 2008 Wiley-Liss, Inc.