Studies have shown that a listener who hears the voice of someone else can infer the speaker's social class, various personality traits, emotional and mental state, and attributes related to deception.
In research with experimental subjects who listen to voice samples from speakers, subjects are then just as capable of correctly estimating the height, weight, and age of those speakers with the same degree of accuracy as that achieved by examining photographs of those speakers. They both correctly estimate the height, weight, and age of speakers 75 per cent of the time.
This was the conclusion of a study by Dr Robert Krauss and colleagues from the Department of Psychology at Columbia University and published in the Journal of Experimental Social Psychology in 2002.
I'm not sure if I believe that or not, but I certainly think I can picture a stranger when I hear their voice on the phone. If I then meet them in person, however, I'm often very surprised.