Why do we prefer John as manager over Mary? Why is this particular CEO more effective than the others? Why does CEO Peter earn a higher salary than CEO Matthew? Who will win the next presidential or government election?
The surprising answer is that their voice may have something to do with it.
New research shows that a deep voice confers benefits in competition for leadership positions in business. A research team from Duke University and the University of California studied the speeches fof the male CEOs of almots 800 public companies. They found that the CEOs with the deeper voices managed larger companies and thus made more money. A decrease of 25% in voice pitch (22.1 Hz) is associated with an increase of $187.000 in annual salary. Moreover, CEOS with deeper voices also enjoy longer tenures.
This sounds like a good argument for taking voice training if you want to succeed in business. The same holds for political success.
In a previous version of this blog I already discussed research on political leaders which basically shows the same. Deeper voiced male politicans have more electoral success. A research team led by Canadian evolutionary psychologist David Feinberg, shows that we prefer political leaders with low voice pitches.
The researchers used archive recordings of former US presidents and manipulated these tapes to create lower and higher pitched versions of each voice. They manipulated the voice pitch by raising or lowering the original pitch by 20 Hz (Incidentally, there is free Voice Changer software available on the web, developed by scientists at the University of Amsterdam, with which you can experiment with your own voice -- great fun!).
They then asked over 100 volunteers to rate these individuals in terms of their leadership potential, integrity, and dominance, and they also asked them whether they preferred them as leaders in national elections and also as war time leaders. In all cases, the participants, both men and women, preferred the leaders with lower pitched voices.
Because the participants might have recognized the presidents by their voices, they conducted a second study in which students were asked to cast their vote for a candidate political leader with either a low or high voice pitch. Again, the participants overwhelmingly preferred the low pitched guy.
Why? There are good evolutionary arguments for these preferences. In human evolutionary history, it would have been important for our ancestors to pay attention to cues of good leadership. And because many of the leadership challenges were physical - like defending the group against a predator -- maybe humans have evolved to pay attention to cues of dominance. A low voice pitch essentially conveys: "I am a strong individual and therefore I can protect you." In the Canadian study the researchers indeed found that individuals with low voice pitches were thought to be more dominant, masculine, and physically formidable. Just like a muscular body, a low voice pitch is an indication of high levels of testosterone.
Earlier research on US-presidential elections from 1960 until 2000 already found that candidates with lower voice frequencies won the popular vote in all elections. Furthermore, politicians with attractive voices are more popular than politicians with less attractive voices. Now we finally know what constitutes an attractive leader voice: A low pitch voice.
This reminds me of one of the great war time leaders of history, Sir Winston Churchill, whose famous radio speeches lifted a whole nation during the Second World War. Listening to his famous "Blood, toil, tears and sweat" speech on 13 May 1940 makes me think that his voice pitch may have had a lot to do with his charismatic influence. It is sad to think that in the modern televised world, Winston Churchill might not have emerged as political leader.
There are still many puzzles about voice pitch and leadership. First, does the ideal pitch depend on the political situation? Churchill's low pitched voice was ideally suited to calm a nation that faced an imminent war threat. Yet, our leadership preferences might switch during peace time. In a recent study, we found that voters preferred a more feminine looking leader in peace time.. Perhaps, voters might opt for someone with a slightly higher voice pitch to maintain peace. That's what we are currently looking at in our evolutionary social and organizational psychology lab at the VU University Amsterdam.
Finally, does voice pitch also influence perceptions of women leaders? Do female politicians and managers display more authority when they have a lower voice pitch. We do not know the answer yet, but it would surely be plausible. The former British prime-minister Margaret Thatcher had a voice coach who helped her train a lower voice to sound more dominant. Yet, according to voice experts, she lost some credibility because it sounded like she was not genuine. That's the problem with a low voice pitch, you can't fake it easily.
So here is a tip for the next time you vote. If you are truly interested in what politicians have to say rather than how they say it, turn off the sound of your TV and try lip-reading.
 Mayew et al, (2013),. Voice pitch and the labor market success of male chief executive officers. Evolution and Human Behavior, 34, 243-248.
 Tigue et al. (2011). Voice pitch influences voting behavior. Evolution and Human Behavior.
 Gregory and Gallagher (2002). Spectral analysis of candidates' nonverbal vocal communication. Social Psychology Quarterly.
 Spisak et al. (2001). Facing the situation: Studying leadership using masculine and feminine faces . Leadership Quarterly.