VI. Earth Life Emergence: Development of Body, Brain, Selves and Societies
1. The Evolution of Cerebral Form and Cognizance
Brown, William. Natural Selection of Mammalian Brain Components. Trends in Ecology & Evolution. 16/9, 2001. Recent findings advise that cerebral anatomy is influenced by a species specific ‘mosaic’ evolution. An ‘adaptationist’ view is proposed in addition to the ‘developmental constraints hypothesis’ of a concerted size increase, which is driven by the need for expanded environmental knowledge.
Because the midbrain has visual and auditory structures, the neocortex and midbrain expansions of the insectivores support the idea that there has been an elaboration in mammals of neural capacities to integrate multimodal information to create perceptual representations of increasingly complex 3D niches. (472)
Bshary, Redouan, et al. Social Cognition in Fishes. Trends in Cognitive Sciences. 18/9, 2014. A recent spate of research reports find that deep down a similar neural anatomy persists across animal kingdoms from its pre-Cambrian origins. Building on these findings, University of Neuchatel biologists and a Cambridge University zoologist propose such aquatic creatures as candidates to study group behavior and cooperation. There are differences among species, but as cases confirm, nuclei networks, cerebellum functions, lateralizations, and more seem highly conserved from a common origin. As a result, the notice and study of “collective cognition” as based on reciprocation is recommended.
Brain evolution has often been correlated with the cognitive demands of social life. Further progress depends on our ability to link cognitive processes to corresponding brain part sizes and structures, and, ultimately, to demonstrate causality. Recent research suggests that fishes are suitable to test general hypotheses about vertebrate social cognition and its evolution: brain structure and physiology are rather conserved among vertebrates, and fish are able to perform complex decisions in social context. Here, we outline the opportunities for experimentation and comparative studies using fish as model systems, as well as some current shortcomings in fish social cognition research. (Abstract)
Burger, Joseph, et al. Toward a Metabolic Theory of Life History. Proceedings of the National Academy of Sciences. 116/26653, 2019. Evolutionary ecologists posted in North Carolina, Missouri and New Mexico (James Brown) can now proceed to visualize and discern broadly applicable patterns and processes across the vast species diorama that past decades have put together.
The life histories of animals reflect the allocation of metabolic energy to traits that determine fitness and the pace of living. Here, we extend metabolic theories to address how demography and mass–energy balance constrain biomass for survival, growth, and reproduction over a life cycle of one generation. Evolution has generated enormous diversity of body sizes, morphologies, physiologies, ecologies, and life histories across the millions of animal, plant, and microbe species, yet simple rules specified by general equations highlight the underlying unity of life. (Abstract excerpt)
Burish, Mark, et al. Brain Architecture and Social Complexity in Modern and Ancient Birds. Brain, Behavior and Evolution. 63/2, 2004. On parallels between telencephalic forebrain size fraction and the intricacy of social groups. This evolution is then seen to converge with that of mammals.
Burkhardt, Pawel and Simon Sprecher. Evolutionary Origin of Synapses and Neurons. BioEssays. Online September, 2017. Marine Biological Association, UK and University of Fribourg, Switzerland neurobiologists delve even deeper into life’s sensory quickenings to fully quantify life’s ramifying course of cognitive development. Once again it is possible to trace this neural facility all the way to their earliest invertebrate rudiments. But it remains curious that at our late hour of global cognizance, they are still likened to machinery.
The evolutionary origin of synapses and neurons is an enigmatic subject that inspires much debate. Non-bilaterian metazoans, both with and without neurons and their closest relatives already contain many components of the molecular toolkits for synapse functions. The origin of these components and their assembly into ancient synaptic signaling machineries are particularly important in light of recent findings on the phylogeny of non-bilaterian metazoans. The evolution of synapses and neurons are often discussed only from a metazoan perspective leaving a considerable gap in our understanding. By taking an integrative approach we highlight the need to consider different, but extremely relevant phyla and to include the closest unicellular relatives of metazoans, the ichthyosporeans, filastereans and choanoflagellates, to fully understand the evolutionary origin of synapses and neurons. This approach allows for a detailed understanding of when and how the first pre- and postsynaptic signaling machineries evolved. (Abstract)
Carruthers, Peter, et al, eds. The Innate Mind. Oxford: Oxford University Press, 2005. An initial volume from the Innateness and the Structure of the Mind project (http://www.shef.ac.uk/philosophy/AHRB-Project) which seeks to advance and update nativist theories due to Noam Chomsky, but which can be traced back to Plato. In contrast to empiricism or constructivism whereby the brain develops mainly in response to external experience, these contents explain and verify that internal propensities do indeed guide cerebral maturation. Typical authors are Gary Marcus, Dan Sperber, Elizabeth Spelke, Daniel Povinelli, and Leah Cosmides, who range from modular brain architecture to language, theory of mind and behavior.
Cela-Conde, Camilo, et al. In the Light of Evolution VII: The Human Mental Machinery. Proceedings of the National Academy of Sciences. 110/Supple. 2, 2013. With coauthors Raul Gutierrez Lombardo, John Avise and Francisco Ayala, an introduction to this survey of our sapient emergence from life’s singular neural and cognitive encephalization. The title phrase “mental machinery” is from one of Charles Darwin’s notebooks. After many decades of research since, by worldwide collaborations, the 16 articles achieve a consummate retrospective. Contributors such as Robert Seyfarth and Dorothy Cheney on “Affiliation, Empathy, and the Origins of Theory of Mind,” Timothy Allen and Norbert Fortin’s “The Evolution of Episodic Memory,” Sarah Brosnan on “Justice and Fairness-Related Behaviors in Nonhuman Primates” and “Similarity in Form and Function of the Hippocampus in Rodents, Monkeys, and Humans” by Robert Clark and Larry Squire, well trace and scope how we late progeny came to be. See also below “Evolution of Consciousness” by George Mashour and Michael Alkire in this issue.
To understand the evolution of a Theory of Mind, we need to understand the selective factors that might have jumpstarted its initial evolution. We argue that a subconscious, reflexive appreciation of others’ intentions, emotions, and perspectives is at the roots of even the most complex forms of Theory of Mind and that these abilities may have evolved because natural selection has favored individuals that are motivated to empathize with others and attend to their social interactions. These skills are adaptive because they are essential to forming strong, enduring social bonds, which in turn enhance reproductive success. (Seyfarth, Cheney)
Changeux, Jean=Pierre, et al. A Connectomic Hypothesis for the Hominization of the Brain. Cerebral Cortex. 31/5, 2021. Pasteur Institute, Paris, and Hamburg University neuroscientists including Claus Hilgetag provide a latest integrative explanation of our cerebral attributes by a novel emphasis on their dense multiplex, genomic-like interconnections. While human brains contain some 87 billion neurons vs. 6.4 billion for macaques, adding in network dynamics further distinguished homo sapiens. One is then led to muse about whomever is this emergent Earthomo planetary facility that can in retrospect learn all this.
Cognitive abilities of the human brain have expanded over the course of our recent evolution from nonhuman primates, with minimum genetic changes. In regard, what we propose relies upon cerebral connectivities which form an anatomical, functional, and computational neural phenotype. An enhanced brain and global neural architecture of primate brains, resulted in a larger number of neurons and the sparsification, modularity, and laminar differentiation of cortical connections. The combination of these features with larger cortical layers, postnatal brain growth, and nongenetic interactions with the physical, social, and cultural evolution gives rise to categorically human-specific cognitive and linguistic abilities. Thus, a small set of genetic regulatory events may account for the origins of human brain connectivity and cognition. (Abstract excerpt)
Changizi, Mark. Principles Underlying Mammalian Neocortical Scaling. Biological Cybernetics. 84/3, 2001. The same fractal self-similarity that describes organic forms and metabolic functions likewise applies to the brain.
The first part of the model is a special case of the physico-mathematical model recently put forward to explain the quarter power scaling laws in biology. It states that the neocortex is a space-filling neural network through which materials are efficiently transported, and that synapse sizes do not vary as a function of gray matter volume. The second part of the model states that the neocortex is economically organized into functionally specialized areas whose extent of area-interconnectedness does not vary as a function of gray matter volume. (207)
Chein, Jason and Walter Schneider. The Brain’s Learning and Control Architecture. Current Directions in Psychological Science. 21/2, 2012. Per the quote, Temple University and University of Pittsburgh neuroscientists propose a triadic evolutionary cerebral pyramid of an older, initial “representation system,” with a 300 million year old reptilian origin, a “cognitive control network” mammalian feature some 60 mya, topped off by our hominid “metacognitive system.” So we people are the executors of evolution, which appears as a long embryonic awakening of a universe trying to remember, recognize, and individuate itself.
Many brain-imaging studies are designed with the goal of isolating brain regions responsible for a specific mental function. The results, which reveal islands of activity scattered about the brain, can give the impression that the brain is just a disorganized collection of specialized processing centers. However, examination of how brain activity changes as a new skill is learned reveals a structured learning architecture composed of three hierarchically organized systems, each with a distinct role in learning and each characterized by a distinct pattern of learning-dependent plasticity. These systems are a representation system, which supports associative learning; a cognitive control network, which allocates attention during the execution of newly learned behaviors; and a metacognitive system, which guides the establishment of new behavioral routines, monitors the quality of ongoing behaviors, and oversees the transitions from one behavior to another. The combined involvement of these systems allows humans to learn rapidly and to flexibly transfer existing knowledge to novel contexts. (Abstract, 78)
Clark, Damon, et al. Scalable Architecture in Mammalian Brains. Nature. 411/189, 2001. The growing quantification of a linear expansion of modular component and overall brain size during animal evolution.
Within each taxon, brain regions are scalable, tending to maintain fixed proportionality of size to one another independent of absolute total brain volume. This suggests that, within a taxon, the development of multiple brain regions is governed by a common set of mechanisms. (192)
Paleopoetics: The Evolution of the Preliterate Imagination.
New York: Columbia University Press,
From our late vantage an emeritus New York University cultural scholar reconstructs the ancient neural and cognitive course of how life came to express itself and ones natural surround by way of poetic image and rhetorical utterance. Again Merlin Donald’s episodic, mimetic, mythic, and theoretic stages from primates to people are a guide. But as the second quote evokes, a novel advance is to trace a “dual-process” mental sequence from original holistic scenarios to a serial, discrete, object mode as proto-languages arose. Collins goes on to cite a similarity with right and left brain hemisphere attributes, rarely do you find this evident connection. By virtue of this temporal sequence, an archetypal complementarity of both yin and yang-like phases, per the fourth quote, can be affirmed.
As for my particular venture into Big History, its ultimate purpose is not simply to time-travel to earlier stages in the evolution of the human mind but rather to explore the depths you and I have within our minds here and now, those deep foundations within which certain strings of words have the power to resonate with astonishing results. Accordingly, my first premise is this: the human brain is an embodiment of its own evolutionary narrative. My second premise is that, broadly defined, poetry is the brain’s use of language to recover knowledge that is at once deeply past and deeply present. (9)