In this era of computer chats and cellphone messages, hearing the voice of someone who loves you -- your mom, especially -- still carries a mighty biological boost at stressful times.
A text just isn't enough, say researchers, who have found that among the virtues of voice is the ability to comfort at tense times.
In a 2011 University of Wisconsin study, 68 girls, ages 7 to 12, were given a public-speaking assignment that resulted in high levels of the stress hormone cortisol in their bodies. One group was allowed to see, touch and talk to their mothers. Another group communicated with them via instant messaging. A third talked to their mothers by phone only, and a fourth group had no contact at all. When hormone production was measured again, the girls who had heard their mother's voice produced more oxytocin, which is associated with positive feelings, and the level of the stress hormone dropped.
"There is something about the power of the human voice that is a lot like touch or other kinds of physical contact in that it can release social hormones and decrease stress," says the study's lead author, Leslie Seltzer, a biological anthropologist. "Communication online, like instant messaging, doesn't appear to have the same effect."
That's not surprising since humans have had a million or so years to learn the intimacies of vocal communication, while written communication has been around a mere 5,000 or 6,000 years.
"There's so much more information in the voice over and above the words being spoken," says Rebecca Brand, an associate professor of psychology at Villanova University. "You have all of the sound information and the timing information and the word information. In text, the timing's not clear, the emotions are not clear, and the familiarity of whatever you respond to in the sounds is missing."