There are other noteworthy characteristics of this rock art style: Anthropomorphs without headdresses instead sport horns, or antennae, or a series of concentric circles. Also prominent in many of the figures' hands are scepters--each one an expression of something significant in the natural world. Some look like lightning bolts, some like snakes; other burst from the fingers like stalks of ricegrass. Colorado Plateau rock-art expert Polly Schaafsma has interpreted these figures as otherworldly--drawn by shamans in isolated and special locations, seemingly as part of a ceremonial retreat. Schaafsma and others believe that the style reflects a spirituality common to all hunter-gatherer societies across the globe--a way of life that appreciates the natural world and employs the use of visions to gain understanding and appreciation of the human relationship to the earth. Typically, Schaafsma says, it is a spirituality that identifies strongly with animals and other aspects of nature--and one that does so with an interdependent rather than dominant perspective. To underscore the importance of art in such a culture, Schaafsma points to Aboriginal Australians, noting how, in a so-called primitive society, where forms of written and oral communication are considered (at least by our standards) to be limited, making art is "one means of defining the mystic tenets of one's faith.