Textbooks often include lengthy elaborations (details supporting the main idea) in an effort to aid student learning of the main ideas. Yet research supporting the efficacy of elaborations is lacking. Passages that include a longer, more detailed explanation of the main ideas take longer to read. Is the additional time cost outweighed by the benefit elaborations afford to memory of the main ideas? We tested this question by giving participants either elaborated or unelaborated versions of the text. We used two authentic textbook passages, one about memory and the other about language, from psychology textbooks. We extracted the main ideas from each passage to create the unelaborated version of the text, keeping the wording of the main ideas consistent in each version. Reading was self-paced to estimate the time cost of elaborations within expository texts. Two days later, we tested our subjects’ memory using a cued recall test and comprehension using a test that required application in novel situations. Across two experiments, the results showed the elaborated versions took longer to read but led to similar levels of performance on tests of both memory and comprehension. Therefore, we can conclude that texts with elaborations may be less efficient than texts without elaborations.