A study of the University of Chicago, in EE. UU., Found that in a human relationship not only physical contact has an important role: the voice is also a fundamental piece.
To reach this conclusion, 61 girls between 7 and 12 years of age were analyzed together with their mothers. The group was divided into three: in the first, the mothers called their daughters by telephone; in the second they gave them a hug; in the third the girls saw a neutral movie without contact with their parents.
The results showed that in the first two groups there was an increase in oxytocin (one of the so-called happiness hormones), while in the third there was no change. The experiment proved that the ears of the girls, upon hearing the voice of their mothers, send stimuli to the brain similar to those that are generated when they embrace them.
According to the results, the distance that separates mothers and daughters is shortened - really - through a call, it is like embracing with the voice.