A blueprint for vocal learning: auditory predispositions from brains to genomes

Memorizing and producing complex strings of sound are requirements for spoken human language. We share these behaviours with likely more than 4000 species of songbirds, making birds our primary model for studying the cognitive basis of vocal learning and, more generally, an important model for how memories are encoded in the brain. In songbirds, as in humans, the sounds that a juvenile learns later in life depend on auditory memories formed early in development. Experiments on a wide variety of songbird species suggest that the formation and lability of these auditory memories, in turn, depend on auditory predispositions that stimulate learning when a juvenile hears relevant, species-typical sounds. We review evidence that variation in key features of these auditory predispositions are determined by variation in genes underlying the development of the auditory system. We argue that increased investigation of the neuronal basis of auditory predispositions expressed early in life in combination with modern comparative genomic approaches may provide insights into the evolution of vocal learning.     

On the Relationship Between Memes and Genes: A Critique of Dennett

Dennett (1995) argues that memes or cultural replicators are largely autonomous of genes, and that they are fairly efficacious in determining who we are and what we do. I argue that Dennett's arguments are wrong in several aspects, which we can see by analyzing processes at appropriate levels. Specifically, I argue that it is not true that we as persons are created largely by memes, that our memes are not largely independent of our genes, and that we can use the universality of memes to make inferences about genetic predispositions. Finally, by suggesting an innate psychological mechanism for morality, I argue that morality may be largely the effect of genetic predispositions rather than autonomous.     

Understanding well-being in the evolutionary context of brain development

Much of the work on well-being and positive emotions has tended to focus on the adult, partly because this is when problems are manifest and well-being often becomes an issue by its absence. However, it is pertinent to ask if early life events might engender certain predispositions that have consequences for adult well-being. The human brain undergoes much of its growth and development postnatally until the age of seven and continues to extend its synaptic connections well into the second decade. Indeed, the prefrontal association cortex, areas of the brain concerned with forward planning and regulatory control of emotional behaviour, continue to develop until the age of 20. In this article, I consider the significance of this extended postnatal developmental period for brain maturation and how brain evolution has encompassed certain biological changes and predispositions that, with our modern lifestyle, represent risk factors for well-being. An awareness of these sensitive phases in brain development is important in understanding how we might facilitate secure relationships and high self-esteem in our children. This will provide the firm foundations on which to develop meaningful lifestyles and relationships that are crucial to well-being.     

Introductory gestures before songbird vocal displays are shaped by learning and biological predispositions

Numerous animal displays begin with introductory gestures. For example, lizards start their head-bobbing displays with introductory push-ups, and many songbirds begin their vocal displays by repeating introductory notes (INs) before producing their learned song. Among songbirds, the acoustic structure and the number of INs produced before song vary considerably between individuals in a species. While similar variation in songs between individuals is a result of learning, whether variations in INs are also due to learning remains poorly understood. Here, using natural and experimental tutoring with male zebra finches, we show that mean IN number and IN acoustic structure are learned from a tutor. Interestingly, IN properties and how well INs were learned, were not correlated with the accuracy of song imitation and only weakly correlated with some features of songs that followed. Finally, birds artificially tutored with songs lacking INs still repeated vocalizations that resembled INs, before their songs, suggesting biological predispositions in IN production. These results demonstrate that INs, just like song elements, are shaped both by learning and biological predispositions. More generally, our results suggest mechanisms for generating variation in introductory gestures between individuals while still maintaining the species-specific structure of complex displays like birdsong.     

CAN REINFORCEMENT OCCUR WITH A LEARNED TRAIT?

We use birdsong as a case study to ask whether reinforcement can occur via the spread of a genetically determined female preference for a socially inherited (learned) male trait. We envision secondary contact between two neighboring populations with different song dialects. An individual's ability to learn song is confined by a genetic predisposition: if predispositions are strong, there will be no phenotypic overlap in song between populations, whereas weak predispositions allow phenotypic overlap, or "mixed" song. To determine if reinforcement has occurred, we consider if an allele for within-population female mating preference, based on song, can spread, and whether population specific songs can concurrently be maintained at equilibrium. We model several scenarios, including costs to mating preferences, mating preferences in hybrids, and hybrids having the ability to learn pure songs. We find that when weak predispositions are fixed within a population reinforcement based on song cannot occur. However, when some individuals have strong predispositions, restricting phenotypic overlap between populations in the trait, reinforcement is only slightly inhibited from a purely genetic model. Generalizing beyond the example of song, we conclude that socially learned signals will tend to prohibit reinforcement, but it may still occur if some individuals acquire trait phenotypes genetically.     

Kant on epigenesis, monogenesis and human nature: the biological premises of anthropology

The aim of this paper is to show that for Kant, a combination of epigenesis and monogenesis is the condition of possibility of anthropology as he conceives of it and that moreover, this has crucial implications for the biological dimension of his account of human nature. More precisely, I begin by arguing that Kant's conception of mankind as a natural species is based on two premises: firstly the biological unity of the human species (monogenesis of the human races); and secondly the existence of 'seeds' which may or may not develop depending on the environment (epigenesis of human natural predispositions). I then turn to Kant's account of man's natural predispositions and show that far from being limited to the issue of races, it encompasses unexpected human features such as gender, temperaments and nations. These predispositions, I argue, are means to the realisation of Nature's overall purpose for the human species. This allows me to conclude that man's biological determinism leads to the species' preservation, cultivation and civilisation.     

Chronic Granulomatous Disease; fundamental stages in our understanding of CGD

It has been 50 years since chronic granulomatous disease was first reported as a disease which fatally affected the ability of children to survive infections. Various milestone discoveries from the insufficient ability of patients' leucocytes to destroy microbial particles to the underlying genetic predispositions through which the disease is inherited have had important consequences. Longterm antibiotic prophylaxis has helped to fight infections associated with chronic granulomatous disease while the steady progress in bone marrow transplantation and the prospect of gene therapy are hailed as long awaited permanent treatment options. This review unearths the important findings by scientists that have led to our current understanding of the disease.     

Culture and the evolution of obesity

Human predispositions to fatness and obesity are best understood in the context of cultural and biological evolution. Both genes and cultural traits that were adaptive in the context of past food scarcities play a role today in the etiology of maladaptive adult obesity. The etiology of obesity must account for the social distribution of the condition with regard to gender, ethnicity, social class, and economic modernization. This distribution, which has changed throughout history, undoubtedly involves cultural factors. A model of culture is presented that has advantages over an undifferentiated concept of the “environment” for hypothesis generation. Cultural predispositions to obesity are found in the productive economy, the mode of reproduction, social structure, and cultural beliefs about food and ideal body size. Cross-cultural comparison can contribute to an understanding of the prevalence of obesity in some modern affluent societies.     

Rothmund–Thomson syndrome helicase,RECQ4: On the crossroad between DNA replication and repair

RECQ proteins are conserved DNA helicases in both prokaryotes and eukaryotes. The importance of the RECQ family helicases in human health is demonstrated by their roles as cancer suppressors that are vital for preserving genome integrity. Mutations in one of the RECQ family proteins, RECQ4, not only result in developmental abnormalities and cancer predispositions, but are also linked to premature aging. Therefore, defining the function and regulation of the RECQ4 protein is fundamental to our understanding of both the aging process and cancer pathogenesis. This review will summarize the clinical effect of RECQ4 in human health, and discuss the recent progress and debate in defining the complex molecular function of RECQ4 in DNA metabolism.     

Tokens improve capuchin performance in the reverse–reward contingency task

In humans and apes, one of the most adaptive functions of symbols is to inhibit strong behavioural predispositions. However, to our knowledge, no study has yet investigated whether using symbols provides some advantage to non-ape primates. We aimed to trace the evolutionary roots of symbolic competence by examining whether tokens improve performance in the reverse–reward contingency task in capuchin monkeys, which diverged from the human lineage approximately 35 Ma. Eight capuchins chose between: (i) two food quantities, (ii) two quantities of ‘low-symbolic distance tokens’ (each corresponding to one unit of food), and (iii) two ‘high-symbolic distance tokens’ (each corresponding to a different amount of food). In all conditions, subjects had to select the smaller quantity to obtain the larger reward. No procedural modifications were employed. Tokens did improve performance: five subjects succeeded with high-symbolic distance tokens, though only one succeeded with food, and none succeeded with low-symbolic distance tokens. Moreover, two of the five subjects transferred the rule to novel token combinations. Learning effects or preference reversals could not account for the successful performance with high-symbolic distance tokens. This is, to our knowledge, the first demonstration that tokens do allow monkeys to inhibit strong behavioural predispositions, as occurs in chimpanzees and children.     

Evaluation of Factors Affecting Emotional Responses in Zoo Visitors and the Impact of Emotion on Conservation Mindedness

Creating experiences for visitors that increase their biological knowledge and inspire conservation mindedness is a critical task for zoos and aquariums. A growing body of literature suggests that emotional stimulation is affected by characteristics of both the visitor and the visitor's experiences and is important for learning and inspiring pro-environmental sentiment. In this study we explored relationships between emotional experience, the factors that influence it, visitors' predispositions toward nature, and their reports of conservation mindedness after viewing three carnivore exhibits at the Bronx Zoo, USA. We surveyed visitors after they viewed tigers, African wild dogs, and spotted hyenas during baseline conditions or when the animals were given environmental enrichment to stimulate natural behavior and activity. We asked visitors to report their predispositions toward nature, the extent of positive emotional experiences they had while viewing the animals, and how the experience affected their conservation mindedness. Environmental enrichment significantly increased animal behavioral diversity, particularly for African wild dogs, and contributed to visitors reporting having had an up-close encounter with the animals, both of which affected the strength of positive emotional experiences at the exhibits. The extent of eye contact with the animal and the animal species also significantly affected emotional responses. Women reported stronger emotional experiences than men, however younger adults did not experience stronger positive emotional responses than older participants. Visitors' predispositions toward nature and emotional responses were significantly correlated. Strong predispositions toward nature and emotional experiences produced significantly stronger reports of conservation mindedness in visitors as a result of their experience at the exhibit. These findings have implications for animal husbandry, exhibit design, education, and outreach efforts for zoos.     

More males run fast: A stable sex difference in competitiveness in U.S. distance runners

Sex differences in competitiveness are well established, but it is unknown if they originate from sociocultural conditions or evolved predispositions. Testing these hypotheses requires a quantifiable sex difference in competitiveness and the application of a powerful sociocultural manipulation to eliminate it. Study 1 reviews previous work showing that more male distance runners are motivated by competition and maintain large training volumes, suggesting that more males should run fast relative to sex-specific world-class standards. I then use two independent statistical approaches to demonstrate that, in matched populations of male and female U.S. runners, two to four times as many males as females ran relatively fast in 2003. Study 2 investigates whether the growth in opportunities and incentives for female athletes in the past 30 years is eliminating this sex difference. I first show that there was a marked increase in the number of fast female runners in the 1970s and early 1980s, a period during which female participation increased dramatically. However, I found no indication of an absolute or relative increase in the number of fast female distance runners since the mid-1980s. These findings therefore support the hypothesis that sex differences in competitiveness partly reflect evolved predispositions.     

Predicting impaired extinction of traumatic memory and elevated startle

Background

Emotionally traumatic experiences can lead to debilitating anxiety disorders, such as phobias and Post-Traumatic Stress Disorder (PTSD). Exposure to such experiences, however, is not sufficient to induce pathology, as only up to one quarter of people exposed to such events develop PTSD. These statistics, combined with findings that smaller hippocampal size prior to the trauma is associated with higher risk of developing PTSD, suggest that there are pre-disposing factors for such pathology. Because prospective studies in humans are limited and costly, investigating such pre-dispositions, and thus advancing understanding of the genesis of such pathologies, requires the use of animal models where predispositions are identified before the emotional trauma. Most existing animal models are retrospective: they classify subjects as those with or without a PTSD-like phenotype long after experiencing a traumatic event. Attempts to create prospective animal models have been largely unsuccessful.

Methodology/Principal Findings

Here we report that individual predispositions to a PTSD-like phenotype, consisting of impaired rate and magnitude of extinction of an emotionally traumatic event coupled with long-lasting elevation of acoustic startle responses, can be revealed following exposure to a mild stressor, but before experiencing emotional trauma. We compare, in rats, the utility of several classification criteria and report that a combination of criteria based on acoustic startle responses and behavior in an anxiogenic environment is a reliable predictor of a PTSD-like phenotype.

Conclusions/Significance

There are individual predispositions to developing impaired extinction and elevated acoustic startle that can be identified after exposure to a mildly stressful event, which by itself does not induce such a behavioral phenotype. The model presented here is a valuable tool for studying the etiology and pathophysiology of anxiety disorders and provides a platform for testing behavioral and pharmacological interventions that can reduce the probability of developing pathologic behaviors associated with such disorders.     

Culture evolves

Culture pervades human lives and has allowed our species to create niches all around the world and its oceans, in ways quite unlike any other primate. Indeed, our cultural nature appears so distinctive that it is often thought to separate humanity from the rest of nature and the Darwinian forces that shape it. A contrary view arises through the recent discoveries of a diverse range of disciplines, here brought together to illustrate the scope of a burgeoning field of cultural evolution and to facilitate cross-disciplinary fertilization. Each approach emphasizes important linkages between culture and evolutionary biology rather than quarantining one from the other. Recent studies reveal that processes important in cultural transmission are more widespread and significant across the animal kingdom than earlier recognized, with important implications for evolutionary theory. Recent archaeological discoveries have pushed back the origins of human culture to much more ancient times than traditionally thought. These developments suggest previously unidentified continuities between animal and human culture. A third new array of discoveries concerns the later diversification of human cultures, where the operations of Darwinian-like processes are identified, in part, through scientific methods borrowed from biology. Finally, surprising discoveries have been made about the imprint of cultural evolution in the predispositions of human minds for cultural transmission.     

Quantitative integration of genetic factors in the learning and production of canary song

Learned bird song is influenced by inherited predispositions. The canary is a model system for the interaction of genes and learning on behaviour, especially because some strains have undergone artificial selection for song. In this study, roller canaries (bred for low-pitched songs) and border canaries (whose song is higher pitched, similar to the wild-type) were interbred and backcrossed to produce 58 males that sorted into seven genetically distinct groups. All males were tutored with the same set of songs, which included both low- and high-pitched syllables. Individuals were consistent within genetic groups but differed between groups in the proportion of low- versus high-pitched syllables they learned and sang. Both sex-linked and autosomal factors affected song learning and song production, in an additive manner. Dominant Z-chromosome factors facilitated high-pitched syllable learning and production, whereas the sex-linked alleles associated with the switch to low-pitched syllables under artificial selection were largely recessive. With respect to autosomal effects, the most surprising result is that males in the same genetic group had almost identical repertoires. This result challenges two common preconceptions: that genetic changes at different loci lead to distinct phenotypic changes, and that genetic predispositions affect learning in simple and general ways. Rather, different combinations of genetic changes can be associated with the same phenotypic effect; and predispositions can be remarkably specific, such as a tendency to learn and sing one song element rather than another.     

Disruption of chromosome 11 in canine fibrosarcomas highlights an unusual variability of CDKN2B in dogs

Background  

In dogs in the western world neoplasia constitutes the most frequently diagnosed cause of death. Although there appear to be similarities between canine and human cancers, rather little is known about the cytogenetic and molecular alterations in canine tumours. Different dog breeds are susceptible to different types of cancer, but the genetic basis of the great majority of these predispositions has yet to be discovered. In some retriever breeds there is a high incidence of soft tissue sarcomas and we have previously reported alterations of chromosomes 11 and 30 in two poorly differentiated fibrosarcomas. Here we extend our observations and present a case report on detail rearrangements on chromosome 11 as well as genetic variations in a tumour suppressor gene in normal dogs.     

Instrumental behaviour of Zoo orang-utans

Recent observations and experiments on the instrumental behaviour of Zoo orang-utans show that the catalogue of actions involving tools hitherto drawn up for these apes has to be substantially enlarged. This paper is a summary of the new findings. Special aspects of instrumental behaviour (predispositions of orang-utans, methodological points on the classical tasks of tool behaviour, comparison between orang-utans and chimpanzees) are discussed.     

Association between the single nucleotide variants of the mitochondrial cytochrome B gene (MT-CYB) and the male infertility

Molecular Biology Reports - Idiopathic male infertility can be attributed to genetic predispositions that affect sperm performance and function. Genetic alterations in the mitochondrial DNA (mtDNA)...     

The brain and the law

Much has been written about how law as an institution has developed to solve many problems that human societies face. Inherent in all of these explanations are models of how humans make decisions. This article discusses what current neuroscience research tells us about the mechanisms of human decision making of particular relevance to law. This research indicates that humans are both more capable of solving many problems than standard economic models predict, but also limited in ways those models ignore. This article discusses how law is both shaped by our cognitive processes and also shapes them. The article considers some of the implications of this research for improving our understanding of how our current legal regimes operate and how the law can be structured to take advantage of our neural mechanisms to improve social welfare.     

Developmental origins of pregnancy-induced cardiac changes: establishment of a novel model using the atrial natriuretic peptide gene-disrupted mice

Molecular and Cellular Biochemistry - Pregnancy evokes many challenges on the maternal cardiovascular system that may unmask predispositions for future disease. This is particularly evident for...