In comparison to other species, humans are not unusually diverse in their appearance and other obvious physical characteristics, but we can easily recognize someone from these small differences in appearance or the sound of their voice. Human behavior is astoundingly diverse. This diversity of human behavior is partly because our unusually complex minds enable us to come up with unpredictable new behaviors, but a lot of the diversity in human behavior is is caused by there being so many different specialized skills and ways of life that we can learn from other people.