This study considers a corpus of conversational data from a cognitive perspective. The corpus is comprised of a set of dialogues involving a man interviewing his parents about memories of the Oklahoma frontier. The study views this conversation in cognitive terms as a process in which the interlocutors' separate cognitive systems interact by means of the speech signal and change as a result. Cognitive systems are viewed as networks of relationships. It is shown that the consideration of natural conversation yields insights into the cognitive structures and processing of interlocutors, and conversely, that an understanding of cognitive systems is needed to explain surface patterns observable in conversational texts. Several issues concerning the interaction of cognitive systems are addressed. First, the patterning of conversational topic is investigated to discover how the speaker designates topics within his cognitive system and how speaker and listener coordinate their notions of topic. The behavior of cognitive topic is found to be governed by a principle of accessibility. Of all the information in the network that a speaker could designate as topic, that information which is most accessible will be selected. For the addressee, the less accessible a new topic is, the less likely he is to recognize it and the more carefully the speaker must prepare him. Second, two cases of multiple tellings of a single experience are investigated to find what they reveal about how the speaker stores and expresses first-hand information. A continuum of storage types is proposed that is characterized by factors such as the number of times a memory has been related, the fluency of the delivery, and the amount of sensitivity shown to the listener's cognitive needs. Finally, the range of cognitive tasks interlocutors perform as they exchange information is explored. The functions served by statements in a portion of conversation are examined, and it is proposed that statement functions are unified by a protypical function, that of reporting on information present in the speaker's system. An interpretation of the cognitive effect of statements is suggested which recognizes five basic cognitive situations of information exchange in which statements are employed.