"Our findings suggest that whether it's parents attempting to assert authority over unruly children, haggling between a car salesman and customer, or negotiations between heads of states, the sound of the voices involved may profoundly determine the outcome of those interactions," said psychological scientist and lead researcher Sei Jin Ko of San Diego State University.
The researchers were inspired by former UK prime minister Margaret Thatcher to investigate the relationship between acoustic cues and power.
"We wanted to explore how something so fundamental as power might elicit changes in the way a voice sounds, and how these situational vocal changes impact the way listeners perceive and behave toward the speakers," Ko said.
In the first experiment, researchers recorded 161 college students reading a passage aloud; this first recording captured baseline acoustics.
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The participants were then randomly assigned them to play a specific role in an ensuing negotiation exercise.
Students assigned to a "high" rank were told to go into the negotiation imagining that they either had a strong alternative offer, valuable inside information, or high status in the workplace, or they were asked to recall an experience in which they had power before the negotiation started.
The students then read a second passage aloud, as if they were leading off negotiations with their imaginary adversary, and their voices were recorded.
Everyone read the same opening, allowing the researchers to examine acoustics while holding the speech content constant across all participants.
Comparing the first and second recordings, the researchers found that the voices of students assigned to high-power roles tended to go up in pitch, become more monotone (less variable in pitch), and become more variable in loudness than the voices of students assigned low-power roles.
Listeners ranked speakers who had been assigned to the high-rank group as more likely to engage in high-power behaviours, and they were able to categorise whether a speaker had high or low rank with considerable accuracy.
The research was published in Psychological Science, a journal of the Association for Psychological Science.