There is a long and ever-growing literature on how human biology influences how we perceive and treat each other. Within this broad area of inquiry, linguists and psychologists have focused on the influence of voice pitch, the “highness” or “lowness” of the voice as determined by the physiology of the throat. In short, a variety of studies show that men and women with lower voices are seen as stronger and more dominant.
At the time our group started the research described below, no one had yet applied these types of results to the world of politics. My wife and co-author, Rindy C. Anderson, is an expert in birdsong, a non-verbal vocal signal just like voice pitch. As I tell audiences when we discuss our work, if you take my wife’s background with acoustics and birds, mine in political science, and put it into a proverbial “blender,” the result is the type of research we’ve been producing for more than five years.
What we have found over a series of experiments and observational studies of real elections in the U.S. is that voters, regardless of their gender, tend to prefer candidates with lower-pitched voices. In subsequent work, we found that this relationship largely boils down to perceptions of competence and strength: we prefer candidates with lower voices because they sound stronger and more competent.
As a political scientist, these findings led me to question whether voice pitch leads us to make “good” decisions at the polls. To wit, are candidates with lower-sounding voice actually better leaders?
Answering this question was not immediately straightforward; we needed both measures of leadership ability and measures of the elected officials’ voice pitch. Thankfully a team of academics, former legislative aids, and other researchers created a “power index” for the 109th meeting of the U.S. Congress (2005-2006). These rankings were based on these experts’ opinions as well as more objective measures of leadership capacity, including seniority, prestige of committee assignments, positions of leadership in the House and Senate, and influence on the legislative agenda, among others. With the help of our research assistants, we paired these power rankings with measures of each Member of Congress’ voice pitch.
The subsequent analysis we conducted was fairly straightforward. Simply stated, is there any correlation between voice pitch and leadership ability? We found none in the 109th U.S. Congress; no relationship between voice pitch and the power ranking index. To follow up on this observational finding, we also conducted an experiment where we manipulated recorded voices digitally to see if lower voices were more persuasive when making policy appeals (e.g., “You should support lower taxes,” or “You should support stronger gun control laws,” and the like). Here again, we found no result; the lower voices were not more persuasive.
In sum, the data we gathered address a critical normative question: is the bias in favor of selecting leaders with lower voices beneficial or detrimental to self-governance? Both the observational and experimental studies we conducted suggest that neither is the case. That is, voter bias in favor of leaders with lower voices is neither “good” nor “bad” for democracy. Voters, on some level, are affected by this non-verbal vocal signal, but this bias does not influence the quality of leaders they select.
These findings are described in greater detail in the article entitled Voice pitch predicts electability, but does not signal leadership ability, recently published in the journal Evolution and Human Behavior. This work was conducted by Casey A. Klofstad from the University of Miami, and Rindy C. Anderson from Florida Atlantic University. We would also like to acknowledge our previous collaborations on this topic with Susan Peters and Stephen Nowicki of Duke University. We also thank Monica Bustinza and Irvenie Latortue for invaluable research assistance.