From GPS devices to voicemail boxes, most computerized voices are female. The reason likely boils down to psychology. Scientific studies have found that humans prefer the sound of a woman's voice to a man's. The preference begins at an early age, too. Stanford University professor Clifford Nass cites a study in which fetuses react to their mother's voice, but not to other female voices or their father's voice. Another possible reason for all of the female computer voices? Our history, says CNN's Brandon Griggs.