We 've long know that a parent's voice has a measurable effect on their children. Infants search for their parents when they hear their voices, and often the sound of mom or dad on the other end of the phone can soothe and calm an upset child when the babysitter's not enough. However, for older children, it seems that the same principles hold true. A new study by Leslie Seltzer, anthropologist from the University of Wisconsin, shows that although IM and texting are convenient ways of relaying messages, they're no substitute for actually hearing a parent's voice. This is primarily because of the release of oxytocin, a feel-good hormone that counteracts the stress-hormone cortisol in our systems, when we're hearing mom's voice.

The study took 64 girls between the ages of 7 and 12, and sat them down in front of three impassively observing adults and asked to solve difficult math problems (a stressful situation for any preteen). After finishing the problems the girls were assigned to one of four different groups; girls that had a face-to-face conversation with their mothers, girls that talked to their mothers by phone, girls that IM'ed their mothers, and girls that didn't talk to their mothers at all. Researchers then took urine samples from the girls to measure oxytocin and saliva samples to measure changes in cortisol levels. The results showed that girls that spoke with their mothers in person or by phone showed markedly higher drops in stress levels, while the stress levels in girls that had chatted in IM with their mothers were no different than the girls that hadn't spoken with their mom at all. The conclusion? "According to Seltzer, the results suggest that mom’s voice — its tones and intonations and rhythms, known formally as prosodics — trigger soothing effects, rather than what she specifically says," from Wired.com

Seltzer concluded her statement by saying, “IM isn’t really a substitute for in-person or over-the-phone interaction in terms of the hormones released. People still need to interact the way we evolved to interact.” Just as IM, text, and the written word in general has proven unequal to the human voice for conveying emotion, so too does it lack the power to illicit biological responses within us. That, Seltzer implies, is only developed after eons of human interaction have written it into our very DNA. Maybe after another several thousands years or more, glued to our cellphones and computer screens, our body's may evolve to physiologically respond to the text of an IM. Of course, my guess is that by that time, we'll have developed some mind-meld device that makes these kinds of studies obsolete.