Music and philosophical naturalism

<p>The philosophical and scientific explication of music is a cutting-edge field in contemporary academia. This thesis develops a naturalistic framework for theorising about music. The following novel philosophical positions are motivated and defended: a polysemy analysis of “sound”, conceptual pluralism about music, a pluralistic framework for approaching the science of music, and a fictionalist account of Western musical artworks. The adaptation/ by-product framework for couching discussion about the evolution of music is critiqued. A novel, co-evolutionary, niche construction model of the foundations of musicality and the origins, expansion and stabilisation of music is developed, couched in the general context of hominin evolution and prehistory. Conceptual and methodological reflection accompanies the evolutionary scenario developed.</p>

Music and philosophical naturalism

<p>The philosophical and scientific explication of music is a cutting-edge field in contemporary academia. This thesis develops a naturalistic framework for theorising about music. The following novel philosophical positions are motivated and defended: a polysemy analysis of “sound”, conceptual pluralism about music, a pluralistic framework for approaching the science of music, and a fictionalist account of Western musical artworks. The adaptation/ by-product framework for couching discussion about the evolution of music is critiqued. A novel, co-evolutionary, niche construction model of the foundations of musicality and the origins, expansion and stabilisation of music is developed, couched in the general context of hominin evolution and prehistory. Conceptual and methodological reflection accompanies the evolutionary scenario developed.</p>

The Creative Neurons

Creativity generates novel solutions to tasks by processing information. Imagination and mental representations are part of the creative process; we can mull over ideas of our own making, and construct algorithms or scenarios from them. Social scenario-building can be viewed as a human cognitive “super-power” that involves abstraction, meta-representation, time-travel, and directed imaginative thought. We humans have a “theater in our minds” to play out a near-infinite array of social strategies and contingencies. Here we propose an integrative model for why and how humans evolved extraordinary creative abilities. We posit that a key aspect of hominin evolution involved relatively open and fluid social relationships among communities, enabled by a unique extended family structure similar to that of contemporary hunter-gatherer band societies. Intercommunity relationships facilitated the rapid flow of information—“Culture”—that underpinned arms-races in information processing, language, imagination, and creativity that distinguishes humans from other species.

The Invention of Fistfighting

It has been hypothesized that key aspects of human male upper limb and facial morphology evolved through selective pressures related to fistfighting. Based on the primatological, archaeological, and ethnographic evidence, I argue these proposals are misguided. An important trend during recent hominin evolution was a decline in upper body strength and facial robusticity, coinciding in part with the rise of complex tools and weaponry. Consistent with this, dueling with weapons is a more a salient form of male-male conflict and conflict management than fistfighting across contemporary hunter-gatherer societies. Among foragers in the Standard-Cross-Cultural Sample (SCCS), fistfighting is comparatively rare, while wrestling is widespread, and dueling with weapons falls in between. I emphasize that hypotheses regarding human evolutionary history should be evaluated carefully against the cross-species, cross-cultural, and historical evidence.

Possible vertebral brucellosis infection in a Neanderthal

The La Chapelle-aux-Saints 1 skeleton of an old (>60-year-old) male Neanderthal is renowned for the advanced osteoarthritis of its spinal column and hip joint, and their implications for posture and lifestyle in these Mid- to Late Pleistocene humans. Reassessment of the pathologic lesions reveals erosions at multiple non-contiguous vertebrae and reactive bone formation extending far beyond the left hip joint, which suggests the additional diagnosis of brucellosis. This implies the earliest secure evidence of this zoonotic disease in hominin evolution. Brucellosis might have been transmitted via butchering or eating raw meat and is well compatible with the range of prey animals documented for Neanderthals. The associated infertility could have represented an important aspect of health in these late archaic humans.

The Significance of Chimpanzee Occipital Asymmetry to Hominin Evolution

Little is known about how occipital lobe asymmetry, width, and height interact to contribute to the operculation of the posterior parietal lobe, despite the utility of knowing this for understanding the relative reduction in the size of the occipital lobe and the increase in the size of the posterior parietal lobe during human brain evolution. Here, we use linear measurements taken on 3D virtual brain surfaces obtained from 83 chimpanzees to study these traits as they apply to operculation of the posterior occipital parietal arcus or bridging gyrus. Asymmetry in this bridging gyrus visibility provides a unique opportunity to study both the human ancestral and human equivalently normal condition in the same individual. Our results show that all three traits (occipital lobe asymmetry, width, and height) are related to this operculation and bridging gyrus visibility but width and not height is the best predictor, against expectations, suggesting that relative reduction of the occipital lobe and exposure of the posterior parietal is a complex phenomenon.

Psychedelics, Sociality, and Human Evolution

Our hominin ancestors inevitably encountered and likely ingested psychedelic mushrooms throughout their evolutionary history. This assertion is supported by current understanding of: early hominins’ paleodiet and paleoecology; primate phylogeny of mycophagical and self-medicative behaviors; and the biogeography of psilocybin-containing fungi. These lines of evidence indicate mushrooms (including bioactive species) have been a relevant resource since the Pliocene, when hominins intensified exploitation of forest floor foods. Psilocybin and similar psychedelics that primarily target the serotonin 2A receptor subtype stimulate an active coping strategy response that may provide an enhanced capacity for adaptive changes through a flexible and associative mode of cognition. Such psychedelics also alter emotional processing, self-regulation, and social behavior, often having enduring effects on individual and group well-being and sociality. A homeostatic and drug instrumentalization perspective suggests that incidental inclusion of psychedelics in the diet of hominins, and their eventual addition to rituals and institutions of early humans could have conferred selective advantages. Hominin evolution occurred in an ever-changing, and at times quickly changing, environmental landscape and entailed advancement into a socio-cognitive niche, i.e., the development of a socially interdependent lifeway based on reasoning, cooperative communication, and social learning. In this context, psychedelics’ effects in enhancing sociality, imagination, eloquence, and suggestibility may have increased adaptability and fitness. We present interdisciplinary evidence for a model of psychedelic instrumentalization focused on four interrelated instrumentalization goals: management of psychological distress and treatment of health problems; enhanced social interaction and interpersonal relations; facilitation of collective ritual and religious activities; and enhanced group decision-making. The socio-cognitive niche was simultaneously a selection pressure and an adaptive response, and was partially constructed by hominins through their activities and their choices. Therefore, the evolutionary scenario put forward suggests that integration of psilocybin into ancient diet, communal practice, and proto-religious activity may have enhanced hominin response to the socio-cognitive niche, while also aiding in its creation. In particular, the interpersonal and prosocial effects of psilocybin may have mediated the expansion of social bonding mechanisms such as laughter, music, storytelling, and religion, imposing a systematic bias on the selective environment that favored selection for prosociality in our lineage.

The loss of the ‘pelvic step’ in human evolution

ABSTRACT Human bipedalism entails relatively short strides compared with facultatively bipedal primates. Unique non-sagittal-plane motions associated with bipedalism may account for part of this discrepancy. Pelvic rotation anteriorly translates the hip, contributing to bipedal stride length (i.e. the ‘pelvic step’). Facultative bipedalism in non-human primates entails much larger pelvic rotation than in humans, suggesting that a larger pelvic step may contribute to their relatively longer strides. We collected data on the pelvic step in bipedal chimpanzees and over a wide speed range of human walking. At matched dimensionless speeds, humans have 26.7% shorter dimensionless strides, and a pelvic step 5.4 times smaller than bipedal chimpanzees. Differences in pelvic rotation explain 31.8% of the difference in dimensionless stride length between the two species. We suggest that relative stride lengths and the pelvic step have been significantly reduced throughout the course of hominin evolution.

The Scapegoat Mechanism in Human Evolution: An Analysis of René Girard’s Hypothesis on the Process of Hominization

According to anthropological philosopher René Girard (1923–2015), an important human adaptation is our propensity to victimize or scapegoat. He argued that other traits upon which human sociality depends would have destabilized primate dominance-based social hierarchies, making conspecific conflict a limiting factor in hominin evolution. He surmised that a novel mechanism for inhibiting intragroup conflict must have emerged contemporaneously with our social traits, and speculated that this was the tendency to spontaneously unite around the victimization of single individuals. He described an unconscious tendency to both ascribe blame and to imbue the accused with a sacred mystique. This emotionally cathartic scapegoat mechanism, he claimed, enhanced social cohesion, and was the origin of religion, mythology, sacrifice, ritual, cultural institutions, and social norms. It would have functioned by modifying the beliefs and behaviors of the group, rather than of the accused, making the act of accusation more important than the substance. This article aims to examine the empirical evidence for Girard’s claims, and argues that the scapegoat hypothesis has commonalities with several other evolutionary hypotheses, including Wrangham’s execution hypothesis on self-domestication, Dunbar’s hypothesis on the role of storytelling in maintaining group stability, and DeScioli and Kurzban’s hypothesis on the role of non-consequentialist morality in curtailing conflict. Potential implications of the scapegoat hypothesis for evolutionary psychology and psychiatry are discussed.

Abrupt change in North African hydroclimate and landscape evolution 3.2 million years ago

Dark organic-rich layers (sapropels) have accumulated in Mediterranean sediments since the Miocene due to deep-sea dysoxia and enhanced carbon burial at times of intensified North African run-off during ‘Green’ Sahara Periods (GSPs). The existence of orbital precession-dominated Saharan aridity/humidity cycles is well known, but lack of long-term, high-resolution records hinders understanding of their precise relationships with environmental and hominin evolution. Here we present continuous, high-resolution geochemical and environmental magnetic records for the Eastern Mediterranean that span the past 5.2 million years, which reveal that organic burial in sapropels intensified 3.2 Myr ago. We deduce that fluvial terrigenous sediment inputs during GSPs doubled abruptly at this time, whereas monsoon run-off intensity remained relatively constant. We attribute the increase in sediment mobilisation to an abrupt non-linear North African landscape response associated with a major increase in arid:humid contrasts between GSPs and intervening dry periods. This likely limited hominin (and other animal) inhabitation of, and migration through, the Sahara region to GSPs only.