Hypotheses regarding the selective pressures driving the threefold increase in the size of the hominid brain since Homo habilis include climatic conditions, ecological demands, and social competition. We provide a multivariate analysis that enables the simultaneous assessment of variables representing each of these potential selective forces. Data were collated for latitude, prevalence of harmful parasites, mean annual temperature, and variation in annual temperature for the location of 175 hominid crania dating from 1.9 million to 10 thousand years ago. We (...) also included a proxy for population density and two indexes of paleoclimatic variability for the time at which each cranium was discovered. Results revealed independent contributions of population density, variation in paleoclimate, and temperature variation to the prediction of change in hominid cranial capacity (CC). Although the effects of paleoclimatic variability and temperature variation provide support for climatic hypotheses, the proxy for population density predicted more unique variance in CC than all other variables. The pattern suggests multiple pressures drove hominid brain evolution and that the core selective force was social competition. (shrink)

Biological evolution and technological innovation, while differing in many respects, also share common features. In particular, implementation of a new technology in the market is analogous to the spreading of a new genetic trait in a population. Technological innovation may occur either through the accumulation of quantitative changes, as in the development of the ocean clipper, or it may be initiated by a new combination of features or subsystems, as in the case of steamships. Other examples of the latter (...) type are electric networks that combine the generation, distribution, and use of electricity, and containerized transportation that combines standardized containers, logistics, and ships. Biological evolution proceeds, phenotypically, in many small steps, but at the genetic level novel features may arise not only through the accumulation of many small, common mutational changes, but also when distinct, relatively rare genetic changes are followed by many further mutations. In particular, capabilities of biologically modern man may have been initiated, perhaps some 150 000 years ago, by one or few accidental but distinct combinations of modules and subroutines of gene regulation which are involved in the generation of the neural network in the cerebral cortex. It is even conceivable that it was one primary genetic event that initiated the evolution of biologically modern man, introducing some novel but subtle feature of connectivity into the cerebral cortex which allowed for meta-levels of abstraction and upgraded modes of information processing. This may have set the stage for the evolution of integrated but diverse higher capabilities such as structured language, symbolic thought, strategic thought, and cognition based empathy. (shrink)

This target article presents a plausible evolutionary scenario for the emergence of the neural preconditions for language in the hominid lineage. In pleistocene primate lineages there was a paired evolutionary expansion of frontal and parietal neocortex (through certain well-documented adaptive changes associated with manipulative behaviors) resulting, in ancestral hominids, in an incipient Broca's region and in a configurationally unique junction of the parietal, occipital, and temporal lobes of the brain (the POT). On our view, the development of the POT (...) in our ancestors resulted in the neuroanatomical substrate consistent with the ability for representations in modality-neutral association cortex and, as a result of structure-imposing interaction with Broca's area, the hierarchically structured Evidence from paleoneurology and comparative primate neuroanatomy is used to argue that Homo habilis (2.5–2 million years ago) was the first hominid to have the appropriate gross neuroanatomical configuration to support conceptual structure. We thus suggest that the neural preconditions for language are met in H. habilis. Finally, we advocate a theory of language acquisition that uses conceptual structure as input to the learning procedures, thus bridging the gap between it and language. (shrink)

Principles of Brain Evolution (Striedter 2005) places little emphasis on natural selection. However, one cannot fully appreciate the diversity of brains across species, nor the evolutionary processes driving such diversity, without an understanding of the effects of natural selection. Had Striedter included more extensive discussions about natural selection, his text would have been more balanced and comprehensive.

The article of Finlay et al. is an excellent example of identifying constraints in the development of the brain, and their implications on brain architecture in evolution. Here we further illustrate the importance of constraints by presenting a few examples of how a small number of biophysical mechanisms or even a single life history parameter can have an enormous impact on brain evolution.

Allometric analyses suggest that there are some developmental constraints on brain evolution. However, when one compares animals of similar body size, these constraints do not appear to be very tight. Moreover, the constraints often differ between taxonomic groups. Therefore, one may ask not only what causes developmental constraints but also how (and why) these constraints might be altered (or circumvented) during the course of evolution.

How does evolution grow bigger brains? It has been widely assumed that growth of individual structures and functional systems in response to niche-specific cognitive challenges is the most plausible mechanism for brain expansion in mammals. Comparison of multiple regressions on allometric data for 131 mammalian species, however, suggests that for 9 of 11 brain structures taxonomic and body size factors are less important than covariance of these major structures with each other. Which structure grows biggest is largely (...) predicted by a conserved order of neurogenesis that can be derived from the basic axial structure of the developing brain. This conserved order of neurogenesis predicts the relative scaling not only of gross brain regions like the isocortex or mesencephalon, but also the level of detail of individual thalamic nuclei. Special selection of particular areas for specific functions does occur, but it is a minor factor compared to the large-scale covariance of the whole brain. The idea that enlarged isocortex could be a a by-product of structural constraints later adapted for various behaviors, contrasts with approaches to selection of particular brain regions for cognitively advanced uses, as is commonly assumed in the case of hominid brain evolution. (shrink)

Brain evolution is a complex weave of species similarities and differences, bound by diverse rules and principles. This book is a detailed examination of these principles, using data from a wide array of vertebrates but minimizing technical details and terminology. It is written for advanced undergraduates, graduate students, and more senior scientists who already know something about “the brain,” but want a deeper understanding of how diverse brains evolved. The book's central theme is that evolutionary changes in (...) absolute brain size tend to correlate with many other aspects of brain structure and function, including the proportional size of individual brain regions, their complexity, and their neuronal connections. To explain these correlations, the book delves into rules of brain development and asks how changes in brain structure impact function and behavior. Two chapters focus specifically on how mammal brains diverged from other brains and how Homo sapiens evolved a very large and “special” brain. Key Words: basal ganglia; cladistics; development; hippocampus; homology; lamination; mammal; neocortex; neuromere; parcellation; primate. (shrink)

Striedter's accessible concept-based book is strong on the macroevolution of brains and the developmental principles that underlie how brains evolve on that scale. In the absence of greater attention to microevolution, natural selection, and sexual selection, however, it is incomplete and not fully modern on the evolution side. Greater biological integration is needed.

The law of coherence helps us understand the physical force behind the increasing complexity of the evolutionary process, from quanta, to cells, to self-awareness and collective consciousness. The coherent electromagnetic field is the inner glue of every system, the "intelligent" energy-information communication that assures a cooperative and synergic behavior to all the components of the system, as a whole, allowing harmonious evolution and unity of consciousness. Neuropsychological experiments show that the different brain areas communicate with more or less (...) coherence according to different states of consciousness: high values are correlated with states of psychophysical integrity and well-being, whereas low values with states of conflict and depression. If we expand isomorphically these brain discoveries, we will have four main general states of coherence: from disgregation to unity, which represents an important element, in the General System Theory, to differentiate between inanimate and animate system, and to understand how billions cells become a single living organism, and then how billions of human beings could eventually generate planetary consciousness. In this light the resolution of the global ecosystem crisis implicates human transformation from a low to a highly coherent state of consciousness. The key to the entire process seems to be the coherent nature of consciousness. (shrink)

Quartz (2002) argues that some recent findings about the evolution of the brain (Finlay & Darlington, 1995) are inconsistent with evolutionary psychologists’ massive modularity hypothesis. In substance, Quartz contends that since the volume of the neocortex evolved in a concerted manner, natural selection did not act on neocortical systems independently of each other, which is a necessary condition for the massive modularity of our cognition to be true. I argue however that Quartz’s argument fails to undermine the massive (...) modularity hypothesis. (shrink)

We review the evidence for the concept of the “initial” or prototype brain. We outline four possible modes of brain evolution suggested by our new findings on the evolutionary status of the dolphin brain. The four modes involve various forms of deviation from and conformity to the hypothesized initial brain type. These include examples of conservative evolution, progressive evolution, and combinations of the two in which features of one or the other become dominant. (...) The four types of neocortical organization in extant mammals may be the result of selective pressures on sensory/motor systems resulting in divergent patterns of brain phylogenesis. A modular “modification/multiplication” hypothesis is proposed as a mechanism of neocortical evolution in eutherians. Representative models of the initial ancestral group of mammals include not only extant basal Insectivora but also Chiroptera; we have found that dolphins and large whales have also retained many features of the archetypal or initial brain. This group evolved from the initial mammalian stock and returned to the aquatic environment some 50 million years ago. This unique experiment of nature shows the effects of radical changes in environment on brain-body adaptations and specializations. Although the dolphin brain has certain quantitative characteristics of the evolutionary changes seen in the higher terrestrial mammals, it has also retained many of the conservative structural features of the initial brain. Its neocortical organization is accordingly different, largely in a quantitative sense, from that of terrestrial models of the initial brain such as the hedgehog. (shrink)

The cerebral cortex controls our most distinguishing higher cognitive functions. Human‐specific gene expression differences are abundant in the cerebral cortex, yet we have only begun to understand how these variations impact brain function. This review discusses the current evidence linking non‐coding regulatory DNA changes, including enhancers, with neocortical evolution. Functional interrogation using animal models reveals converging roles for our genome in key aspects of cortical development including progenitor cell cycle and neuronal signaling. New technologies, including iPS cells and (...) organoids, offer potential alternatives to modeling evolutionary modifications in a relevant species context. Several diseases rooted in the cerebral cortex uniquely manifest in humans compared to other primates, thus highlighting the importance of understanding human brain differences. Future studies of regulatory loci, including those implicated in disease, will collectively help elucidate key cellular and genetic mechanisms underlying our distinguishing cognitive traits. (shrink)

A dorsalization mechanism is a good candidate for the evolutionary origin of the isocortex, producing a radial and tangential expansion of the dorsal pallium (and perhaps other structures that acquired a cortical phenotype). Evidence suggests that a large part of the dorsal ventricular ridge (DVR) of reptiles and birds derives from the embryonic ventral pallium, whereas the isocortex possibly derives mostly from the dorsal pallium. In early mammals, the development of olfactory-hippocampal associative networks may have been pivotal in facilitating the (...) selection of a larger and more complex dorsal pallium which received both collothalamic and lemnothalamic sensory information. Finally, although it is not clear exactly when mammalian brain expansion began, fossil evidence indicates that this was a late event in mammaliaform evolution. (shrink)

Art is a system of human communication arising from symbolic cognition, conveying ideas, experiences, and feelings. The view adopted here is that pictorial representation by artists is influenced by the neurological status of their brain, physiological status of their eyes, biological motivations shared by animals and humans, and by evolutionary adaptive processes expressed uniquely in Homo sapiens. The appearance of art is affected by both sensory and brain systems, and clues can be obtained from damage to either one (...) of these systems. A review of brain-damage effects on artists suggests that artistic talent, skill, and creativity, to say nothing of art-related ideas, are resistant to the damage and are generally diffusely represented in the brain. This is consistent with (1) the view that art is a multi-component system, and (2) with the biological motivation background of art, namely that the display draws on resources not easily associated with localized brain regions. Evolutionary changes have shaped the human brain to be uniquely neuronally “wired-up” to produce art, to interpret it, and to receive pleasure from it. The perspective adopted here is that the neural basis of pictorial art is a multi-regional brain function. (shrink)

Rolls shares important data on hunger, thirst, sexuality, and learned behaviors, but is it pertinent to understanding the fundamental nature of emotionality? Important as such work is for understanding the motivated behaviors of animals, Rolls builds a constructivist theory of emotions and primary-process affective consciousness without considering past evidence on specific types of emotional tendencies and their diverse neural substrates.

First, we clarify the central nature of our argument: our attempt is to apportion variation in brain size between developmental constraint, system-specific change, and change, underlining the unexpectedly large role of developmental constraint, but making no case for exclusivity. We consider the special cases of unusual hypertrophy of single structures in single species, regressive nervous systems, and the unusually variable cerebellum raised by the commentators. We defend the description of the cortex (or any developmentally-constrained structure) as a potential spandrel, (...) and weigh the implications of the spandrel concept for the course of human evolution. The empirical and statistical objections raised in the commentary of Barton are discussed at length. Finally, we catalogue and comment on the suggestions of new ways to study brain evolution, and new aspects of brain evolution to study. (shrink)

Researchers studying primate brain allometry often focus on departures from allometry more than the allometric relationships themselves because only the former reveal what brain regions and behavioral-cognitive abilities were the focus of selection. Allometric departures for the human brain provide insights into hominid brain evolution and cast doubt on the suggestion that the large human cerebral cortex is a.

Constraint has played a major role in brain evolution, but cannot tell the whole story. In primates, adaptive specialization is suggested by the existence of a covarying visual system, and may explain some residual variation in the constraint model. Adaptation may also appear at the microstructural level and in the globally integrated system of brain, body, life history and behavior.

Wilkins & Wakefield (1995) provide a thoughtful contribution to our understanding of language origins. In this commentary I attempt to define the relationship between object-manipulation and primate brain function further by reviewing research on aimed throwing and the production and use of stone tools by tufted capuchin monkeys (Cebtis apella). I propose that examining the relation between brain function and object-manipulation inCebuswill provide insight into the preconditions of language in our hominid ancestors.

One of the key challenges confronting cognitive science is to discover natural categories of cognitive function. Of special interest is the unity or diversity of cognitive control mechanisms. Evolutionary history is an underutilized resource that, together with neuropsychological and neuroscientific evidence, can help to provide a biological ground for the fractionation of cognitive control. Comparative evidence indicates that primate brain evolution has produced dissociable mechanisms for external action control and internal self-regulation, but that most real-world behaviors rely on (...) a combination of these. The archeological record further indicates the timing and context of distinctively human elaborations to these cognitive control functions, including the gradual emergence of increasingly complex hierarchical action control. (shrink)

Within a physicalist-mechanistic worldview, in which we cannot be more than intelligent, self-reproducing biomachines or biobots, fundamentals of a new approach to the science of human self-explanation are outlined. Some a priori logical necessities, or determinants, of any biobot’s control system design are recognized. Evolution had to satisfy them, but neuroscience and cognitive science so far do not clearly see these basics. It is concluded that the old part of the brain still contains the genetically fixed drives, responses, (...) and the physiological control. Here is the seat of an ancient somatic self that is not intelligent but is still the active center of our life. The neocortex has evolved to serve the somatic self with intelligence by individually building a virtual model of the external material and social world. This model is used by the somatic self to “pre-play” intended actions and responses to see whether they would satisfy its needs. This schema of global brain function provides the neurological foundation for the ego-id dichotomy in analytic psychology, as well as some critique of it. Following the groundbreaking experiments by Benjamin Libet and John-Dylan Haynes et al. , consciousness is taken as a “theater” that presents what the neural networks already have worked out, and freedom of the will is limited. The explosive growth of culture and civilization began when neocortical power exceeded a certain threshold. This can be taken as a quasi-mutation that projected us into a supra-biological space of existence that is new to natural history. It is not clear whether this event will lead to a positive future for humanity or to doom. Functional religion is seen as a neurosystemic attempt to bring back the earlier natural state. Thus, it can be valuable when cleared of mythological ballast. (shrink)

The existence of linked regularities in size among brain components across species is, by itself, not a strong argument against the importance of behavioral selection in brain evolution. A careful consideration of hominid brain evolution suggests that brain components can change their scaling relationships over time, and that behavioral selection was likely crucial. The best neuroanatomical index of a given behavioral ability can only be determined empirically, not through comparative analysis of brain anatomy (...) alone. (shrink)

After reviewing historical aspects of brain evolution, this accessible book provides an enjoyable overview of several general principles of brain evolution, culminating in discussions of mammalian and human brains and a framework for future research.

In the vast clade of animals known as the bilateria, cerebral and behavioural asymmetries emerge against the backdrop of bilateral symmetry, with a functional trade-off between the two. Asymmetries can lead to more efficient processing and packaging of internal structures, but at the expense of efficient adaptation to a natural world without systematic left-right bias. Asymmetries may arise through the fissioning of ancestral structures that are largely symmetrical, creating new circuits. In humans these may include asymmetrical adaptations to language and (...) manufacture, and as one or other hemisphere gains dominance for functions that were previously represented bilaterally. This is best illustrated in the evolution of such functions as language and tool manufacture in humans, which may derive from the mirror-neuron system in primates, but similar principles probably apply to the many other asymmetries now evident in a wide range of animals. Asymmetries arise in largely independent manner with multi-genetic sources, rather than as a single over-riding principle. (shrink)

Descartes boldly claimed: "I think, therefore I am." But one might well ask: Why do we think? How? When and why did our human ancestors develop language and culture? In other words, what makes the human mind human? _Evolution of Mind, Brain, and Culture_ offers a comprehensive and scientific investigation of these perennial questions. Fourteen essays bring together the work of archaeologists, cultural and physical anthropologists, psychologists, philosophers, geneticists, a neuroscientist, and an environmental scientist to explore the evolution (...) of the human mind, the brain, and the human capacity for culture. The volume represents and critically engages major theoretical approaches, including Donald's stage theory, Mithen's cathedral model, Tomasello's joint intentionality, and Boyd and Richerson's modeling of the evolution of culture in relation to climate change. The volume contains chapters by: Peter Carruthers; Thierry Chaminade; Philip Chase; Merlin Donald; Peter Gardenfors; Gary Hatfield; Jody Hey; Steven Mithen; April Nowell; Peter Richerson and Robert Boyd; Theodore Schurr; Robert Seyfarth and Dorothy Cheney; Kim Sterelny; and Felix Warneken. ISBN 978-1-934536-49-0. (shrink)

The meme is an evolutionary replicator, defined as information copied from person to person by imitation. I suggest that taking memes into account may provide a better understanding of human evolution in the following way. Memes appeared in human evolution when our ancestors became capable of imitation. From this time on two replicators, memes and genes, coevolved. Successful memes changed the selective environment, favouring genes for the ability to copy them. I have called this process memetic drive. Meme-gene (...) coevolution produced a big brain that is especially good at copying certain kinds of memes. This is an example of the more general process in which a replicator and its replication machinery evolve together. The human brain has been designed not just for the benefit of human genes, but for the replication of memes. It is a selective imitation device. (shrink)

Presenting a landmark in linguistics and cognitive science, Ray Jackendoff proposes a new holistic theory of the relation between the sounds, structure, and meaning of language and their relation to mind and brain. Foundations of Language exhibits the most fundamental new thinking in linguistics since Noam Chomsky's Aspects of the Theory of Syntax in 1965—yet is readable, stylish, and accessible to a wide readership. Along the way it provides new insights on the evolution of language, thought, and communication.

Gerhard Roth's _Evolution of Brains and Minds_ represents a rare and valuable achievement in the neurological and evolutionary literature. It is rare because its author brings an almost unprecedented combination of disciplinary training to bear on the central problem of the mind-brain relationship: Roth holds doctorates in both philosophy and biology (specifically behavioral physiology and neurobiology), and his career has bridged the humanities and natural sciences in ways that few contemporary researchers can claim. It is valuable because it offers (...) a comprehensive, empirically grounded, and philosophically informed synthesis of what is currently known—and what remains unknown—about how nervous systems and cognitive capacities have evolved across the animal kingdom, culminating in the peculiar case of _Homo sapiens_. The book is an English translation and substantial revision of Roth's 2010 German work _Wie einzigartig ist der Mensch? Die lange Evolution der Gehirne und des Geistes_ ("How Unique Is Humanity? The Long Evolution of Brains and Minds"). Rather than a mere translation, the author has taken the opportunity to incorporate new literature that appeared between the German and English editions, revise several chapters extensively, and refine his arguments in light of ongoing debates. The result is a work that stands as a landmark contribution to evolutionary neurobiology, comparative cognition, and the philosophy of mind—one that deserves careful reading by specialists and advanced students across multiple disciplines. (shrink)