I would argue that the Mesopotamian civilization had a greater impact on human development. This is because it was both the first major civilization and, later, the first civilization to invent writing.
Agriculture was not invented in Mesopotamia, but when it came to that area, the Mesopotamians were the first to create a really complex civilization. This civilization was known as the Sumerian civilization. It had a great deal of impact on places such as Egypt. One of its major contributions was the creation of cuneiform, the first system of writing ever known.
Since writing is such an important part of human development, I would argue that the civilization that invented writing had the greatest impact on that development.