A study was conducted to test an hypothesis relating semantic structures to cognitive development, specifically that the mean number of associative complexes used by a group of children will be significantly greater than the mean number of associative complexes used by a group of adolescents. The word game "Password" provided a simulation of a speech communication context. Pilot studies helped determine the test words, the reliability of the judges, and the most effective method of playing the game. Subjects were 54 fourth graders, ages 9 and 10, and 52 high school sophomores and juniors, ages 15 and 16. Clues and guesses were sent and received through the judges, who acted as intermediaries. Although results did indicate that the semantic system differed across the two age groups and that there is a semantic component in speech, associative structures were more prominent when adolescents were engaged in sending behavior and when children were engaged in receiving behavior, a finding opposite of the prediction of the hypothesis. Explanations of this result must be extremely tentative, but perhaps the age range selected for this study was not really representative of a separate semantic state, or perhaps the semantic model is appropriate for decoding but not for encoding. This speculation suggests a fruitful avenue for future research. (JL)