This study investigated the relationship between an observer's familiarity with the normal, truthful communicative behavior of an individual, and the observer's ability to detect deception on the part of that individual. Specifically, an attempt was made to provide an experimental test of the degree of linearity between familiarity and judgmental accuracy in detecting deception. After exposure to varying amounts of a communicator's normal, truthful behavior (baseline segment), observers made judgments of a communicator's veracity following observation of truthful or lying behavior (test segment). The results indicate a significant deviation from linearity in the relationship between familiarity and judgmental accuracy, and that the relationship is better described by an inverted parabolic curve (quadratic function). The possibility of information overload, the possibility of communicator-specific characteristics which provide clues to deception, and the possibility of observer fatigue were proposed as possible explanations of these results.