Anthropologists believe that spindle cells made their first appearance 10 to 15 million years ago in the as yet undiscovered common ancestor to apes and hominids (precursors to humans) and rapidly increased in numbers around 100,000 years ago. Interestingly, spindle cells do not exist in newborn humans but begin to appear only at around the age of four months and increase significantly in number from ages one to three. Children’s ability to deal with moral issues and perceive such higher-level emotions as love develop during this same period.
