I've never heard it explained that way, "spiritually devoid human bodies". I believe they had some spiritual discernment but Adam was placed there to "till the ground", or bring the knowledge of God to the field (the world).
There is a natural sense of a higher power that one gets in nature even if unlearned in His word. As every body contains a soul and our spirit is the intellect of our soul would not those first men and women have felt that basic connection to God?
.......Ping
You have just made a flawless argument for animals having souls.