The project entails basic reserach in the as yet incompletely understood area of human memory for meaning and language. This proposal inquires into the functional structure of human semantic memory for properties, and the retrieval processes which make the information available for language and comprehension. Three core variables are addressed in the research. The property dominance variable suggests that some property information is more important to our knowledge of concepts (wings and fly for robin) than other properties (eyes, feet). Ashcraft's (in press) earlier reaction time research with this variable is being extended to encompass the typicality of concepts (robin vs. duck as members of the category bird). Specifically, semantic priming occurs when subjects are asked to judge related sentences (robin has wings -- sparrow can fly), as evidenced by a reduction in reaction time to the second sentence. Experiments I and II should indicate the degree to which priming can operate between the levels of high and low typicality. The results will not only be original information, but also should lead to a more adequate understanding of human memory for meaning. Experiments III and IV concern the importance of properties (vs. concept names like robin) in the retrieval of semantic information and the influence of general (wings) vs. unique (redbreast) properties on retrieval time. These two studies in particular are open-ended, and should lead to more complex questions for future research. In general, the project involves basic research in the area of semantic memory. The results from the reaction time tasks should provide original information in the area of semantic memory for properties, permit greater theoretical understanding of semantic memory performance, and stimulate new research on human memory for language and meaning.