Dr. Joseph (2011) examines the compelling question of whether Neanderthals could have experienced spirituality. Although the answer may very well be “yes” in the end, at present this question must be approached with tempered enthusiasm. What is a spiritual experience? Here we turn to William James’ notion of spirituality in Homo sapiens. He considered someone’s experience spiritual if their “feelings, acts and experiences” touch “whatever they may consider the divine” (James and Marty, 1982). We can never know what another species considers divine unless they tell us and so far no none has the skill to use symbols (like language) needed to communicate the subjective richness of a spiritual experience. So, we must infer what is spiritual to our species might be spiritual to another.

In H. sapiens many varieties of spiritual experience can be realized. Passions arising from the evolutionarily ancient limbic system, and so crucial to these hallowed moments, sweep a vast domain: elation, reverence, inspiration, grace, mercy, acceptance, joy, relief, awe, fear, love, forgiveness, power and grief -are just a few. Even in H. sapiens these sentiments are not by themselves uniquely spiritual. Most often these feelings are removed from the spiritual and find expression, perhaps more faintly, in ordinary life. If non-humans have the neurological substrate for at least some of theses limbic emotions, how can we surmise if these sentiments have arisen in a spiritual context?

Dr. Joseph presents evidence that Neanderthals might have limbic expressions that could reach the spiritual-in particular the emotions swirling around death. Whether Neanderthals undertook mortuary practices, for otherworldly or other reasons, remains an open question (Gargett, 1999). Objects seemly placed for burial may have other origins that are hidden at first (Sommer, 1999). Strata can mix over large expanses of time, confounding an object’s calculated age (Higham et al., 2010). Predation by animals or Neanderthal cannibals, natural rock falls and other forces could defile the Neanderthal dead, and not represent intentionally banishing spirits from this world. Furthermore, the mortality ill may naturally assume a sleeping posture shortly before taking their last breath.

Although a confluence of evidence indicates that H. sapiens’ primal brain plays a crucial role in spiritual experience, there remains a missing and necessary ingredient for Neanderthal. The H. sapien left hemisphere is not only the seat of language but it is also the hypothesis generator (Wolford et al., 2000), the creator of explanations including those evoking gods. The cerebral hemispheric lateralization leading to complex symbolic conception (and integration into a vibrant reward system) necessary for spiritual interpretation appears to have happened for H. sapiens long after Neanderthal and H. sapien lineages diverged (Enard et al., 2002). There is, as yet, no convincing evidence that Neanderthals engaged in symbolic expression (Mellars, 2010). Even Joseph (2000) has argued that Neanderthals did not have language, which only emerged with the evolution of modern homo sapiens.

If not ornaments or burial to reach the afterlife, is there other evidence for spiritual expressions in Neanderthals?

It is reasonable to assume that Neanderthals had REM sleep and the limbic structures necessary for dreams, but without a symbolic expression of their subjective experience handed down after tens of thousands of years, we can not know how they regarded their dreams, and there’s the rub.

Near-death experience is arguably the dominant spiritual experience of our time. One frequent and dramatic aspect of near-death is out-of body experience or autoscopy. Disrupting the temporoparietal region causes autoscopy, (Blanke et al., 2002, Blanke et al., 2004) probably by disturbing sensory integration into the coherent self. Autoscopy also has a strong relationship with REM consciousness (Mahowald and Schenck, 1992, Overeem et al., 2001, Nelson et al., 2007, LaBerge et al., 1988). The temporoparietal region is selectively inactive during REM consciousness (Maquet et al., 2005). Although autoscopy occurs in almost 6% of the general population (Ohayon, 2000), even in H. sapiens autoscopy is often devoid of spiritual overtones (Nelson, 2011). All mammals and thereby Neanderthals enter REM consciousness, but Neanderthals like some H. sapiens may not have viewed their autoscopy as spiritual.

Likewise Neanderthals are expected to have possessed the limbic structures and serotonin-2a,c neurochemical system that underlie the mystical sense of oneness, considered by William James and W.T. Stace to be the supreme spiritual experience (Stace, 1960). And like dreams, we have no idea if Neanderthal embraced their mystical oneness as touching something divine.

It is reasonable to conclude that other species can experience elements of what H. sapiens consider spiritual. I commend Dr. Joseph for exploring this fascinating topic, but I also urge that we cautiously tread forward as our understanding of the brain, spirituality, genetics and anthropology advances.