This theory is about the body, so it makes any sense of "spirit" subservient to body control (just as it does mind and individuality). But the trans-sensory extremes of experience (sadness, jubilation, curiosity etc) are very like the saturated, coherent ecstatic states reported by mystics and sages over the years, and those people who seem to agree with this theory most instinctively tend to call themselves "spiritual."
Furthermore, many religions have physical practices with clear connections to common body architectures. Consider religious practices which stimulate the body's midline: pressing the head against the ground, pressing the palms together, bowing the head, casting the face upwards. Most religious ceremonies provide synchronous sensations across all sensory modalities, not only sounds and color but even taste and smell. Many involve disciplines which are good for the spine, like yoga. So it may well be that the important, experiential aspects of many if not most religions can be explained--and resurrected in a minimally-biased way!--by a deeply-principled understanding of the musculo-skeletal system.