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Culture (behaviour based on socially transmitted information) is present in diverse animal species, yet how it interacts with genetic evolution remains largely unexplored. Here, we review the evidence for gene-culture coevolution in animals, especially birds, cetaceans and primates. We describe how culture can relax or intensify selection under different circumstances, create new selection pressures by changing ecology or behaviour, and favour adaptations, including in other species. Finally, we illustrate how, through culturally mediated migration and assortative mating, culture can shape population genetic structure and diversity. This evidence suggests strongly that animal culture plays an important evolutionary role, and we encourage explicit analyses of gene-culture coevolution in nature.

Nonhuman primate neuroimaging is on the cusp of a transformation, much in the same way its human counterpart was in 2010, when the Human Connectome Project was launched to accelerate progress. Inspired by an open data-sharing initiative, the global community recently met and, in this article, breaks through obstacles to define its ambitions.

This research was supported by ERC Advanced (EVOCULTURE 232823) and NERC (NE/D010365/1) grants to KNL and grants from the NSF (IOS0744974, DEB1149160), NIH (R01GM115996), and Burroughs Wellcome Fund to MDS. Whether learning primarily reflects general processes or species-specific challenges is a long-standing matter of dispute. Here, we present a comprehensive analysis of public information use (PI-use) in sticklebacks (Gasterosteidae). PI-use is a form of social learning by which animals are able to assess the relative quality of resources, here prey patches, by observing the behaviour of others. PI-use was highly specific with only Pungitius and their closest relative Culaea inconstans showing evidence of PI-use. We saw no effects of ontogenetic experience upon PI-use in Pungitius pungitius. Experiments with live demonstrators and animated fish revealed that heightened activity and feeding strikes by foraging conspecifics are important cues in the transmission of PI. Finally, PI-use was the only form of learning in which P. pungitius and another stickleback, Gasterosteus aculeatus differed. PI-use in sticklebacks is species-specific and may represent an ‘ecological specialization’ for social foraging. Whether this reflects selection on perception, attentional or cognitive processes remains to be determined. Publisher PDF

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Patrick Bateson made outstanding contributions to the study of animal behaviour over a 50-year period, a field in which he was regarded as a world leader. His research involved analyses of the development, causal mechanisms, function and evolution of behaviour, and combined work in the experimental laboratory with observations of the natural behaviour of animals and theoretical analyses. With particular expertise on behavioural development, Bateson made seminal contributions to several topics, including filial imprinting, mate choice, developmental plasticity, the roles of behaviour and development in evolution, animal welfare and animal play. His research on imprinting in birds pioneered new methods, set new standards for behavioural research and shed new light on the interplay of internal and external factors during behavioural development. Recognizing that a complete understanding of behaviour requires investigation at a number of levels, Bateson's interactionist perspective led him to be highly critical of reductionism and of simple-minded use of terms such as ‘instinct’ and ‘innate’. Bateson published several influential books and well over 300 scientific articles, including a substantial number in flagship journals such as Nature and Science. His contribution to science was recognized with many honours, including a knighthood, the Frink medal of the Zoological Society of London and the Distinguished Animal Behaviorist Career Award of the Animal Behavior Society. Bateson was also provost of Kings College Cambridge, president of the Zoological Society of London and biological secretary and vice-president of the Royal Society. A leading public intellectual in the early part of the twenty-first century, Bateson brought leadership and balanced judgement to many difficult issues, including the use of animals in medical research, dog breeding and hunting.

Recognition plays an important role in the formation and organization of animal groups. Many animals are capable of class-level recognition, discriminating, for example, on the basis of species, kinship or familiarity. Individual recognition requires that animals recognize distinct cues, and learn to associate these with the specific individual from which they are derived. In this study, we asked whether sticklebacks ( Gasterosteus aculeatus and Pungitius pungitius ) were capable of learning to recognize individual conspecifics. We have used these fish as model organisms for studying selective social learning, and demonstrating a capacity for individual recognition in these species would provide an exciting opportunity for studying how biases for copying specific individuals shape the dynamics of information transmission. To test for individual recognition, we trained subjects to associate green illumination with the provision of a food reward close to one of two conspecifics, and, for comparison, one of two physical landmarks. Both species were capable of recognizing the rewarded landmark, but neither showed a preference for associating with the rewarded conspecific. Our study provides no evidence for individual recognition in either species. We speculate that the fission–fusion structure of their social groups may not favour a capacity for individual recognition.

Matlab code used in the simulations presented in this paper

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.

The directed social learning hypothesis suggests that information does not spread evenly through animal groups, but rather individual characteristics and patterns of physical proximity guide the social transmission of information along specific pathways. Network-based diffusion analysis (NBDA) allows researchers to test whether information spreads following a social network. However, the explanatory power of different social networks has rarely been compared, and current models do not easily accommodate random effects (e.g. allowing for individuals within groups to correlate in their asocial solving rates). We tested whether the spread of two novel foraging skills through captive starling groups was affected by individual- and group-level random and fixed effects (i.e. sex, age, body condition, dominance rank and demonstrator status) and perching or foraging networks. We extended NBDA to include random effects and conducted model discrimination in a Bayesian context. We found that social learning increased the rate at which birds acquired the novel foraging task solutions by 6.67 times, and acquiring one of the two novel foraging task solutions facilitated the asocial acquisition of the other. Surprisingly, the spread of task solutions followed the perching rather than the foraging social network. Upon acquiring a task solution, foraging performance was facilitated by the presence of group mates. Our results highlight the importance of considering more than one social network when predicting the spread of information through animal groups. This article is part of a Special Issue entitled: Cognition in the wild.

Niche construction refers to the activities of organisms that bring about changes in their environments, many of which are\ud evolutionarily and ecologically consequential. Advocates of niche construction theory (NCT) believe that standard evolutionary theory fails to recognize the full importance of niche construction, and consequently propose a novel view of evolution, in which niche construction and its legacy over time (ecological inheritance) are described as evolutionary processes, equivalent in importance to natural selection. Here, we subject NCT to critical evaluation, in the form of a collaboration between one prominent advocate of NCT, and a team of skeptics. We discuss whether niche construction is an evolutionary process, whether NCT obscures or clarifies how natural selection leads to organismal adaptation, and whether niche construction and natural selection are of equivalent explanatory importance.We also consider whether the literature that promotes NCT overstates the significance of niche construction, whether it is internally coherent, and whether it accurately portrays standard evolutionary theory. Our disagreements reflect a wider dispute within evolutionary theory over whether the neo-Darwinian synthesis is in need of reformulation, as well as different usages of some key terms (e.g., evolutionary process).

Parental care is any form of provisioning that improves offspring survival and can range from brief guarding of young to advanced adaptations such as viviparity. Despite the wide taxonomic spread of care, the evolution of such diversity and its impact on other aspects of species’ life history are not well understood and quantified. Using phylogenetic comparative methods and experimental approaches, I explore how variation in care provision, together with environmental context, affect a range of life-history traits in teleost fishes and passerines. In contrast to birds where advanced and prolonged care dominates, parental care in fishes encompasses a broad spectrum of strategies with varying levels of investment. Chapter 1 provides an overview of research into the evolution of parental care. In Chapter 2, I assess the relative effect of environment and care strategies on variation in offspring size across 1,639 species of marine teleosts. While investment in eggs is driven primarily by temperature, I find that species with parental care exhibit larger sizes at hatching compared to species with no care. I also show that large hatchlings promote the evolution of advanced forms of care but there is no evidence that post-spawning care in general, including simpler forms of care provided predominantly by males, co-evolves with offspring size. In Chapter 3, I use an experimental approach to investigate the potential trade-off between the provision of a safe environment for offspring development and attracting a mate in three-spined stickleback (Gasterosteus aculeatus) males that construct nests. I find that stickleback males build more conspicuous nests on backgrounds that are perceived as safer, but that their investment in nests is balanced against other courtship activities. In Chapter 4, I identify global correlates of variation in nest size using measurements from 1,117 species of cup-nesting passerines. I observe that the pattern of building larger nests in colder environments or habitats with reduced predation threat – first detected at population-level studies – does scale up globally and across a multitude of species. Finally, in Chapter 5, I evaluate the importance of predation and competition in shaping the evolution of nest type and associated life-history traits in passerines. Using data from 4,105 species, I determine that enclosed nests are associated with larger clutch sizes and longer periods of care irrespective of the level of competition in the breeding environment. "This work was supported by the John Templeton Foundation [grant number #60501], the Carnegie Trust [grant number #RIG008238], Systematics Research Fund [Award 2019] and the Fisheries Society of the British Isles [Small Research Grant 2019]." -- Funding

Here I provide an overview of the ways in which phenotypic plasticity is suggested to be relevant to evolutionary dynamics, and examine the various predicted dynamics of plastic traits in novel environments. Following on from this, I use adaptive radiation of threespine stickleback (Gasterosteus aculeatus) into freshwater environments as a model system to examine the dynamics of multiple plastic traits under relaxed selection. I find that - as expected - overall survival plasticity appears to initially increase upon exposure to a novel environment before generally (but not always) decreasing under relaxed selection over time. My results suggest that morphological variation increases in the environments no longer experienced by daughter populations, implying that plasticity declines chiefly through accumulation of drifted cryptic genetic variation. From this I conclude that the plasticity of a trait may be relevant to its evolutionary dynamics (and those of the lineage) in novel environments - and that environment-dependent expression of alleles in rare environmental conditions may represent a limiting factor of adaptive phenotypic plasticity. "This work was supported by the John Templeton Foundation [Grant number 60501: Putting the Extended Evolutionary Synthesis to the Test]; and the FSBI [Small Research Grant: An exploration of the gill physiology underlying salinity tolerance in threespine sticklebacks, Gasterosteus aculeatus]." -- Funding

Behavioural scientists argue that ‘social learning’ provides the link between biological phenomena and cultural phenomena because of its role in the ‘cultural transmission’ of knowledge among individuals within and across generations. However, leading authors within the social sciences have proposed alternative ways of thinking about social life not founded on the Modern oppositions including nature-culture, biology-culture, body-mind, and individual-society. Similarly, the distinction between a domain of nature and a domain of nurture has also been extensively criticized within biology. Finally, advocates of ‘radical embodied cognitive science’ offer an alternative to the representational-computational view of the mind which supports the conventional notion of culture and cultural information. This thesis attempts to integrate developmental systems theory, radical embodied cognitive science, and relational thinking, with the goal to bring the field of social learning closer to these critical theoretical developments. In Chapter 2, I find no justification for the claim that the genome carries information in the sense of specification of biological form. Chapter 3 presents a view of ontogeny as a historical, relational, constructive and contingent process. Chapter 4 uses the notions of environmental information, abilities, affordances, and intentions to make sense of behaviour and learning. In Chapter 5, I argue that the notion of social learning can be understood in terms of relational histories of development rather than in terms of transmission of information. I then report empirical studies investigating behavioural coordination and social learning consistent with this theoretical framework. Chapter 6 presents evidence that dyads in a joint making activity synchronize their attention constrained by their changing situation and that coordination of attention is predictive of implicit and explicit learning. Chapter 7 presents evidence that joint attention does not require gaze following and that attentional coordination is predictive of learning a manual task. Together, these theoretical and empirical studies suggest a new way of thinking about how humans and other animals live and learn socially, one that is consistent with critical theoretical and philosophical developments that are currently neglected in the literature on social learning.

Many animals socially learn, but very few do so through teaching, where an individual modifies its behaviour in order to facilitate learning for another in individual. Teaching behaviour is costly, but can confer numerous advantages, such as high fidelity transmission of information or an increase in the rate of social learning. In many putative cases of teaching, it is not known whether the pupil learns from the modified behaviour. This thesis addresses this issue in three cases of potential teaching behaviour. In particular, it investigates whether the role of food transfers in wild golden lion tamarins is to teach which foods are good to eat (Chapter 5). There was little evidence that novel foods were transferred more than familiar foods, and this was not due to the juveniles attempting to obtain novel foods more than familiar ones, or by adults discarding novel foods more than familiar ones. Transfers were however more successful when donors had previously ingested the food type transferred. Successful food transfers also had a positive correlation with foraging choices once juveniles were older, suggesting they learned from food transfers. In golden lion tamarins, this thesis also examined whether juveniles learned from food-offering calls which substrates were good to forage on (Chapter 6). Juveniles that experienced playback of food-offering calls ate more on a novel substrate, than juveniles that did not experience those playbacks, both immediately as the calls were being played, and in the long term, six months after the playbacks. This suggests that juveniles learned from the playbacks. Finally, this thesis attempted to replicate previous findings showing that hens modify their behaviour when chicks feed from seemingly unpalatable food, and explored whether chicks learned what food to eat based on the maternal display (Chapter 7). The experiment failed to find evidence for teaching behaviour, but results were not inconsistent with previous findings. Moreover, there was little evidence that chicks learned from their mother, quite to the contrary, hens seemed to acquire their foraging decisions based on their chicks’ choices. "The work presented in this thesis was supported by an ERC Advanced Grant and John templeton Foundation Grant to Kevin Laland." -- Acknowledgements

Culture is a hugely important process in the evolution of humans and many non-human animals. Through the formation of long lasting traditions, culture provides an extragenetic inheritance mechanism that can facilitate rapid behavioural adaptation to novel environments. This can ultimately alter the selection pressures acting on different phenotypes including those that underlie cultural transmission itself, i.e. the mechanisms of social learning. Understanding culture poses many challenges for researchers due to the complex nature of interacting biological processes at multiple organisational and temporal scales. In this thesis I investigate some of these complexities through the integration of different theoretical and statistical modelling approaches, and argue that rich models are particularly important for the study of culture. In chapters 3 & 4 I use an evolutionary agent-based model to study the functional value and cultural significance of strategically copying from other individuals based on particular cues, such as age or payoff. I find that a bias to copy the successful can provide substantial adaptive advantages, potentially outweighing other strategic considerations such as when to engage in social learning. I also demonstrate that the strength of selection on social learning strategies is closely linked to the cultural diversity within a population. In chapters 5 & 6 I study the mechanisms of learning and how social influences can impact decision making. In chapter 5 I model the behaviour of nursery children and chimpanzee groups when solving a complex task and identify clear species differences in the importance of different forms of learning on decision making. Finally, in chapter 6 I use an agent-based model to examine the influence of population structure on the spread of novel behaviour. I demonstrate that, contrary to infectious disease type models, when learning occurs through operant conditioning, highly clustered network structures promote cultural transmission rather than hinder it.

There is something unique about human culture. Its complex technologies, customs, institutions, symbolisms and norms, which are shared and maintained and improved across countless generations, are what sets it apart from the ‘cultures’ of other animals. The fundamental question that researchers are only just beginning to unravel is: How do we account for the gap between their ‘cultures’ and ours? The answer lies in a deeper understanding of culture’s complex constituent components: from the micro-level psychological mechanisms that guide and facilitate accurate social learning, to the macro-level cultural processes that unfold within large-scale cooperative groups. This thesis attempts to contribute to two broad themes that are of relevance to this question. The first theme involves the evolution of accurate and high-fidelity cultural transmission. In Chapter 2, a meta-analysis conducted across primate social learning studies finds support for the common assumption that imitative and/or emulative learning mechanisms are required for the high-fidelity transmission of complex instrumental cultural goals. Chapter 3, adopting an experimental study with young children, then questions the claim that mechanisms of high-fidelity copying have reached such heights in our own species that they will even lead us to blindly copy irrelevant, and potentially costly, information. The second theme involves investigations of the mutually reinforcing relationship predicted between cultural complexity and ultra-cooperativeness in humans, employing a series of laboratory-based experimental investigations with adults. Chapter 4 finds only limited support for a positive relationship between cooperative behaviour and behavioural imitation, which is believed to facilitate cultural group cohesion. Finally, Chapter 5 presents evidence suggesting that access to cultural information is positively associated with an individual’s cooperative reputation, and argues that this dynamic might help to scaffold the evolution of increased cultural complexity and cooperation in a learning environment where cultural information carries high value.

Social learning is ubiquitous among animals and humans and is thought to be critical to the widespread success of humans and to the development and evolution of human culture. Evolutionary theory, however, suggests that social learning alone may not be adaptive but that individuals may need to be selective in who and how they copy others. One of the key findings of these evolutionary models (reviewed in Chapter 1) is that social information may be widely adaptive if individuals are able to combine social and asocial sources of information together strategically. However, up until this point the focus of theoretic models has been on the population level consequences of different social learning strategies, and not on how individuals combine social and asocial information on specific tasks. In Chapter 2 I carry out an analysis of how animal learners might incorporate social information into a reinforcement learning framework and find that even limited, low-fidelity copying of actions in an action sequence may combine with asocial learning to result in high fidelity transmission of entire action sequences. In Chapter 3 I describe a series of experiments that find that human learners flexibly use a conformity biased learning strategy to learn from multiple demonstrators depending on demonstrator accuracy, either indicated by environmental cues or past experience with these demonstrators. The chapter reveals close quantitative and qualitative matches between participant's performance and a Bayesian model of social learning. In both Chapters 2 and 3 I find, consistent with previous evolutionary findings, that by combining social and asocial sources of information together individuals are able to learn about the world effectively. Exploring how animals use social learning experimentally can be a substantially more difficult task than exploring human social learning. In Chapter 4, I develop and present a refined version of Network Based Diffusion analysis to provide a statistical framework for inferring social learning mechanisms from animal diffusion experiments. In Chapter 5 I move from examining the effects of social learning at an individual level to examining their population level outcomes and provide an analysis of how fine-grained population structure may alter the spread of novel behaviours through a population. I find that although a learner's social learning strategy and the learnability of a novel behaviour strongly impact how likely the behaviour is to spread through the population, fine grained population structure plays a much smaller role. In Chapter 6 I summarize the results of this thesis, and provide suggestions for future work to understand how individuals, humans and other animals alike, use social information.

The objective of the experiments contained within this thesis was to provide further insight into the social learning capabilities of threespined sticklebacks and the factors affecting the transmission of information through populations. There are a number of previous studies which provide evidence that both threespined and ninespined sticklebacks possess the ability to learn socially under a range of contexts, such as foraging, anti-predator behaviour, mate choice, and cooperation. The studies presented in this thesis aim to extend this knowledge and shed light on the social learning processes used. Evidence was found to support previous opinion that threespined sticklebacks are capable of using a number of social learning processes, including local enhancement, stimulus enhancement, and the social enhancement of food preferences. However, therewas no evidence to suggest that either threespined or ninespined sticklebacks are capable of using the social learning process of delayed local enhancement under a shelter choice context, a process which both species have previously been shown to use under a foraging context. This thesis also explores the effect of the social network within shoals of threespined sticklebacks upon the transmission of novel foraging information. It was discovered that both prior association preferences and prior diet have an effect on the order in which individuals discover a novel foraging task.

Human culture is unique in its scope and complexity and is underpinned by the social transmission of information. Successful individuals will use both social and asocial information effectively. Evolutionary theory suggests that social learning should be guided by evolved learning rules that dictate when individuals rely on social information, a literature which I review across Chapters 1 and 2, with the emphasis of chapter 2 being on conformist transmission. In this thesis I present experimental investigations of the existence and adaptive value of several such strategies in both adults (Chapter 3) and young children (Chapter 4). In all cases I find strong evidence for the existence of such biases and show that they act to increase the accuracy of decisions. In particular I show individuals are highly sensitive to even small majorities within a group of demonstrators. The youngest children (age 3) however, show little sensitivity to social information and do not use it effectively. In Chapter 5 I present an investigation into the role of social learning in the evolution of hominin lithic technology. I conclude that even the earliest hominin flaking technology is poorly transmitted through observation alone and so the widespread and longstanding persistence of such tools implies some form of teaching. Furthermore, I conclude that the stable transmission of more complex technologies would likely require teaching, and potentially symbolic communication. I also postulate a co-evolution of stone tools and complex communication and teaching. In Chapter 6 I conclude that the cultural evolutionary approach, focussing on the evolutionary consequences of social information use and treating culture as a system of inheritance partially independent of genes, seems successful in increasing our understanding of the evolution of social learning.

Corophium volutator (Pallas) fit the criteria of ‘ecosystem engineers’ as defined by Jones and colleagues (1994, 1997): they are widely distributed within and across North Atlantic estuaries, are often present in intertidal soft sediment in vast numbers, and build semi-permanent burrows in the sediment matrix, which they irrigate continuously. Previous studies have demonstrated that C. volutator burrowing and feeding not only modifies the sediment biogeochemistry but can also modify the overlying water biogeochemistry (during immersion). C. volutator activities have also been shown to be detrimental to microphytobenthic (MPB) biofilms in the immediate vicinity of the burrows. As MPB are the stabilizing force in the estuary, the decimation of biofilm destabilizes the habitat for all the organisms colonising it. However, several aspects of C. volutator ecology remain unclear. First, previous studies on the effect of C. volutator on local (within burrow proximity) MPB diversity have not presented a clear signal as to whether they increase or decrease biodiversity or established whether there is preferential survival amongst MPB taxa with certain cell shapes and sizes or lifestyles. Second, as it has been established that C. volutator have the potential to change the water column, it is possible for them to effect MPB populations remotely (outwith burrow proximity). It is therefore of interest to determine the effects they have, whether such an effect can be achieved within a tidal period, and whether these effects can change MPB biomass, behaviour or diversity over time. A series of controlled mesocosm experiments were carried out to quantify those effects of C. volutator on the water column which were likely to impact MPB survival, to determine whether those effects were specific to C. volutator or common to deposit‐feeding bioturbators, to determine to what degree they could be achieved within a single immersion period, and to separate the effects of C. volutator on MPB bulk (chlorophyll-a in top 5 mm) and photosynthesizing (fluorescing) biomass and diversity both ‘locally’ and ‘remotely’. The results of the first 3 experiments consistently showed that C. volutator substantially increased the resuspension of sediment to the overlying water column and that the resulting turbidity could reduce lightpenetration to the sediment by as much as 50% within one immersion period. Results of nutrient fluxes were less consistent and clear within and between experiments but there was some suggestion that increased bioirrigation increased inorganic nitrogen flux to the overlying water column in accordance with previous studies. The effects of C. volutator on local and remote MPB biomass (bulk and surface) and diversity varied between experiments but, broadly speaking: (1) bulk biomass was unaffected, reduced locally, or increased remotely; (2) surface biomass was reduced both locally and remotely; and (3) community diversity (Simpson’s diversity index) was consistently unaffected, both locally and remotely. Because increased water column turbidity is the most distinctive calling card of C. volutator but is only likely to affect the photosynthetically active (surface) MPB biomass during immersion, a controlled laboratory experiment was designed to examine the extent to which turbidity could influence MPB migratory behaviour and photosynthetic activity. MPB bulk migration was shown to be driven by sitespecific, entrained rhythms of light availability and spatial variation in light availability only drove micro‐cycling in the photic zone during the immersion period. So, in the absence of C. volutator, or any other turbidity producing phenomenon (deep water columns, high flow rates, physical disturbance, etc.), MPB will remain at the surface to photosynthesize during immersion and the productivity during this period is determined by total light intensity and exposure hours (or ‘light dose’). Therefore, the proximity and size of C. volutator populations to a site is likely to be influential in determining local productivity patterns of MPB. In addition, differences in MPB assemblage composition were shown to influence the biofilm productivity but what drives changes in MPB assemblage composition is still unclear and requires further investigation.

Humans are unique in the extent and complexity of their cultures. As a species, we generate extensive knowledge and innumerable norms, attitudes, traditions, skills, beliefs and technologies that we share with those around us through teaching, imitation and language. These cultural practices have their roots in our uniquely potent ability for social learning. This thesis sets out to elucidate the process of cultural evolution using a series of mathematical and computational models. These models first investigate the evolution of the capacity for social learning, the rare ability to teach, and the evolution of the smart and strategic use of social learning, in the animal lineage. They go on to investigate the implications of these strategies and mechanisms for culture and find that the form human culture takes is dependant on the amount and nature of social learning as well as on the underlying learning strategies deployed. The thesis also investigates the effect that culture has had on the human evolutionary niche. Cultural practices fundamentally change the selection pressures to which humans are subject and these in turn change both our cultures and our genes through gene-culture coevolution. Finally, a demographic cultural niche construction model is presented, which investigates the application of cultural evolution modelling, cultural niche construction theory and demographic models to the growing problem of sex-ratio imbalance in modern China and considers the implications for policy-making. The analyses presented in this thesis support the argument that the uniquely potent human ability to transmit acquired information through teaching, imitation and other forms of social learning, and through this to shape our cultural and ecological environments, has played and continues to play a central role in human evolution.

Many studies demonstrated the use, and strategies of use, of public information -or the ability of an observer to assess a resource’s quality by watching inadvertent behavioural cues- in the ninespine stickleback (Pungitius pungitius) presented with a foraging patch assessment problem. Many aspects of behaviour were seen to vary with an increased feeding rate and identifying the one responsible for transmission of information is difficult with live demonstrators. This project created and utilized computer-animated ninespine sticklebacks to isolate behaviours and test which ones are used by observers to gain information. We predicted and found that out of six different behaviours associated with an increase in feeding rate, strike rate is the one used to assess foraging patches’ quality. Observer ninespine sticklebacks preferred to associate with sides that were formerly associated with an animated shoal of conspecifics different only in the amount of strikes per demonstration period, in a ratio of six versus two.

Human culture has been proposed to uniquely exhibit a ‘ratchet effect’, with beneficial modifications being made to cultural traits over many generations. This is widely thought to have allowed an accumulation of technology and knowledge over time, and to be of central importance to the remarkable ecological and demographic success of humans. Whilst many researchers argue that the roots of human culture lie in social learning, a process widespread in nature, the exact cognitive capacities that set humans apart are not known. To provide a comparative assessment of nine separate hypotheses regarding different social and cognitive factors that may underlie a capacity for cumulative culture, in this thesis a cumulative puzzlebox was presented to three species. Groups of capuchins, chimpanzees and children were provided with the opportunity to solve the puzzlebox to three sequential levels to retrieve rewards of increasing desirability. Higher level solutions spread only in the children. Evidence was found for the occurrence of teaching, imitation, complex communication and prosociality in groups of children, but not in groups of capuchins and chimpanzees. Furthermore, these processes were positively correlated with the performance of individuals within the groups of children which was the only species to show evidence of cumulative cultural learning. Five further hypotheses focussed on alternative social and cognitive factors were not supported by the evidence from this experiment.

Social learning is known to be a common phenomenon in fish, which they utilise under many different contexts, including foraging, mate-choice and migration. Here I review the literature on social learning in fish and present two studies. The first examines the ability of threespined sticklebacks to use social learning in the enhancement of food preferences. The second study examines the ability of both threespined sticklebacks and ninespined sticklebacks to use social learning in the avoidance of predators.

'Culture' is defined as information, such as knowledge, beliefs, skills, attitudes or values, that is passed from individual to individual via social (or cultural) transmission and expressed in behaviour or artifacts. 'Cultural evolution' holds that this cultural inheritance system is governed by the same Darwinian processes as gene-based biological evolution. In Part A of this thesis it is argued that as compelling a case can now be made for a Darwinian theory of cultural evolution as Darwin himself presented in The Origin Of Species for biological evolution, If culture does indeed evolve, then it follows that the structure of a science of cultural evolution should broadly resemble that of the science of biological evolution. Hence Part A concludes by outlining a unified science of cultural evolution based on the sub-disciplines of evolutionary biology. Parts B and C comprise original empirical and theoretical work constituting two branches of this science of cultural evolution. Part B describes a series of experiments testing for a number of hypothesised biases in cultural transmission. Evidence was found for a 'social bias' that acts to promote information concerning third-party social relationships over equivalent non-social information, and a 'hierarchical bias' that acts to transform knowledge of everyday events from low-level actions into higher-level goals. Three other hypothesised biases concerning status, anthropomorphism and neoteny were not supported, although each gave rise to potential, future work using this methodology. Part C presents a theoretical investigation into the coevolution of the genetic bases of human mating behaviour and culturally inherited folk beliefs regarding paternity. Gene-culture coevolution and agent-based models suggested that beliefs in 'partible paternity' (that more than one man can father a child) create a new more polygamous form of society compared with beliefs in singular paternity (that only one man can father a child).