Fundamental frequency during couple conflict: an analysis of physiological, behavioral, and sex-linked information encoded in vocal expression

The human voice is one of the sounds most frequently experienced by human beings. During couple conflict, higher fundamental frequency (f0), a physical property of human speech, has been linked to an increased risk of divorce, less beneficial response to couple therapy, and higher levels of dysfunctional communication behavior. F0 is generally considered to be a measure of emotional arousal, but it is not currently clear whether this interpretation is appropriate for understanding spouses' f0 during couple interaction. The goal of the current article is to clarify what forms of information are encoded in f0 during couple conflict by examining the relations between f0 range, physiological variables, and communication behavior during the conflict discussions of 67 German couples. In line with evolutionary models of speech production, associations emerged in the expected directions between f0 and: (a) physiological variables (e.g., heart rate, blood pressure, and cortisol); (b) self-reported communication behavior; and (c) observationally coded communication behavior. Additionally, simultaneous examination of physiological variables and observationally coded communication behaviors revealed that associations between both sets of variables and f0 range were largely independent of one another. Furthermore, women's range of f0 was significantly greater than men's range of f0. With regard to social signaling theories, f0 range can be understood as a nonverbal transmission of distress. Implications for future research on and use of f0 are discussed.