Hidden Depths

Front matter

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Chapter 1. The Evolutionary Basis for Human Empathy, Compassion and Generosity Abstract Introduction

How do we respond to another's distress? The neurobiology of compassion

Empathy From empathy to constructive help Growing into our empathy: progressively complex responses through childhood development Disentangling evolutionary mechanisms

Why be kind? The evolutionary advantages of compassionate helping behaviours

Animal comparisons: stages in the evolution of human empathy, compassion and generosity

Comparing non-human apes and humans: emotional capacities and helping behaviours of human ancestors 7 to 8 million years ago

Cognitive empathy Affective empathy Evolutionary pressures on emotional motivations

Implications for the evolution of human empathy, compassion and generosity

Conclusions Key points References

Chapter 2. Material Evidence: caring for adult vulnerabilities Abstract Introduction

Archaeological evidence for the emergence of human compassion and generosity

Before two million years ago: earliest beginnings? Doubts about implications?

The nature of helping in australopithecines After two million years ago: the emergence of ‘humans’ Evidence for care of the ill and injured Care as part of increasing interdependence After half a million years ago: later periods of human evolution

To what extent can archaeological evidence be used to infer key changes in emotional connections and capacities for compassion?

Other realms of material evidence for helping those in need

Implications: a long evolutionary history of human vulnerability, compassion and interdependence

Conclusions Key points References

Chapter 3. Trust, Emotional Commitments and Reputation

Abstract Introduction Trust and a sensitivity to emotional motivations in human evolutionary origins Our human drive to understand the emotions behind other people’s actions

Why early human interdependence made a good reputation matter

Trust, emotional commitments and the price to pay for caring about reputation

55 57 58 60

71 73

76 77 79 81 82 84 89 91

99 104

106 111 112 114

129 131

133 136

The significance of trust, emotional commitments and a concern with reputation to key issues in human origins

Being kind rather than being cunning Reflecting on the cultural transmission of knowledge

Reflecting on the influence of emotional reputation on attention to the aesthetics of artefact form

Reflecting on a sensitivity to emotional motivations and the integration of different minds

Further questions Wired for trust?

Conclusions

Key points References

142 142 144

150 156 158 158 159 160

Chapter 4. The Evolutionary Basis for Human Tolerance - Physiological Responses Abstract Introduction Intergroup tolerance in human evolutionary past

The evolutionary background to human physiological reactions to unfamiliar people

Neurobiology, emotional responses and social behaviour The physiology of changes in avoidance behaviour - how changes in hormones might make us less competitive or fearful Competition and aggression — the role of androgens Fear, stress reactivity and cortisol

The physiology of changes in approach behaviour - how changes in hormones might make us more ‘friendly’

Goal seeking exploration and novelty - the influence of dopamine

Bonding hormones Selective pressures on human tolerance Conclusions Key points References

171 173 174

178 181

184 184 190

193 198 202 203 204 205

Chapter 5. The Evolutionary Basis for Human Tolerance: human ‘self-domestication’? Human self-domestication?

Implications

The advantages of increasing tolerance

The constraints and disadvantages of increasing tolerance Compensatory mechanisms

Chapter 6. Comforting Things: cherished possessions as sources of social comfort and security, from the Palaeolithic to the present

Abstract Introduction

The appearance of widespread non-functional objects in the archaeological record

New emotional relationships to objects?

Compensatory attachments to objects in childhood Compensatory attachments to objects in adulthood

Are there common forms or features to cherished personal objects?

Cultural variations

Art in search of empathy - reappraising the proliferation of symbolic objects

Conclusions Key points References

Chapter 7. In The Company of Wolves: compensatory attachments and the human-dog bond Abstract Introduction Dogs in recent ethnographic contexts

Dogs as a form of technology 301

Dogs as playing a role in emotional wellbeing 304 Dogs as sources of emotional support in modern industrialised contexts 310 Reappraising the domestication of wolves from the perspective of emotional vulnerabilities 311 Archaeological evidence 312 Similar evolutionary pathways in dogs and humans 319 How did wolves become close to humans? 324 Conclusions 327 Key points 328 References 330

Chapter 8. What If? The Evolutionary Basis for Different

Pathways 343 Abstract 343 Introduction 345 Alternative evolutionary pathways in other species 350

Contrasts in tolerance between chimpanzees and bonobos 350

Contrasts in tolerance between wolves and dogs 356 Different but equal human evolutionary pathways? 366 Implications 372 Conclusions 374 Key points 375 References 377

Chapter 9. Reframing Neanderthals 387 Abstract 387 Introduction 390 Different types of ‘social’ 393 Archaeological evidence for contrasting patterns of intergroup connection between neanderthals and modern humans in europe 396

Background 396 Neanderthal community relationships 397

Modern human communities 400

The structure of social networks and contrasting emotional dispositions in social tolerance

Reframing neanderthals as emotionally close-knit and modern humans as emotionally approachable

Differing emotional dispositions explain contrasts in the structure of communities

Differing emotional dispositions explain previously enigmatic elements of the archaeological record

Conclusions Key points References

What have we learnt?

What makes this interpretation different?

Why should this new version of our evolutionary past matter for the future?

Index

415 418 419 421

433 435

440 443

Acknowledgements

Writing a book is often much like taking a journey and, moreover, one that is never made entirely alone. Certainly, on this journey through the evolutionary past of our human emotional connection there has been much help along the way. Perhaps unsurprisingly, not all of this help has been human. l'm profoundly grateful for the constant and unwavering emotional support of Wookie (who is, as you might realise, my dog). She has always been willing to go for a walk to think about things and has been a constant companion, never more than a short distance away for almost every word written. Of course, | am also indebted to the humans around me for their support and patience, as well as more academic input from all the friends and colleagues | have the pleasure to know and who have been happy to listen, discuss and read drafts. Paul Mills has been ever supportive, even through the ‘early draft which for some reason didn’t quite work’, as were Kate and Tom at White Rose University Press. Paul O’Higgins, Calvin Dytham, Celia Deanne Drummond, Elva Robinson, Jenni French, Sam Cobb, Phil Cox, Laura Fitton, Paul Gilbert, Geoff Bailey, Michelle Cree, David Roland, Michelle Brenner, Gail Hitchens, Lucas Ayestaran, Taryn Bell and Callum Scott have been particularly helpful in discussions, advice, helping with references or reading drafts, and particular thanks are due to Kate Petherbridge for her x HIDDEN DEPTHS patience. Mistakes are my own. The John Templeton Foundation made this whole project possible through ‘Hidden Depths, grant reference: 61389, and the Department of Archaeology, University of York, provided sabbatical time. Lastly, | am much indebted to my family for putting up with the agony of all the multiple rephrasing and rewriting that comes along with my dyslexia, particularly my parents, my two sons Matthew and Lucas, and my partner, Chris.

Foreword

When | first started the research for this volume, | set out to reveal the largely unexplored area of archaeological evidence for how some of our closest human emotional connections emerged. The idea for the book came out of the recognition that, all too often, evidence for what we see as the better part of our natures is sidelined or forgotten. Narratives of our human origins tend to either predominantly focus on discussions of violence or aggression, or be framed within ideas of humans as purely rational beings with little emotional motivations of any kind.

Journeys rarely go the way we envisage. Over the nine chapters, we do uncover a remarkable record of care for the vulnerable, collaboration, and inclusion. We learn about the collaborative group effort of early humans, the compassionate motivations of Neanderthals, and new levels of intercommunity tolerance. An evolutionary framework makes sense of why our uniquely human emotional connections, sensitivities and caring motivations may have paid off in our evolutionary past. Furthermore, a more interesting and complex picture than that framed as a simple ladder of progression towards ourselves is presented, with different hominin species xii HIDDEN DEPTHS exploring different evolutionary trajectories, not just of physical form but also of emotional disposition.

However, another and perhaps even more important story also unfolded as the volume was written. This was a story not of virtue but of vulnerability, and one in which we become more the unwitting passengers of evolutionary processes than its heroes. Alongside evidence for care, inclusion and tolerance came an unexpected and rather more precious insight. As our sensitivity to how others feel and our willingness to respond to those who need our help emerged, so too did our own emotional vulnerabilities. Our tendencies to act for the common good are driven by sensitivities around how others may see us. Our willingness to care for our loved ones is underlain by often painful empathy with their suffering. Our motivations to develop friendships and companionship and a sense of belonging to extended communities are motivated by our acute sensitivity to loneliness. All of these vulnerabilities make us who we are and structure how we feel, motivating us to make connections and to give and receive help. Moreover, it is these vulnerabilities that, in turn, also made human groups and communities resilient in the face of adversity. We often deride emotional vulnerability in modern societies. However, when we look in depth at our distant past, it is clear that the more socially sensitive and attuned to others’ feelings we became, the more our species benefited from greater collaboration and connection.

| have been surprised by how little attention human emotional connections and, in particular, emotional vulnerabilities have received in our evolutionary story. Indeed, the role that our emotional lives played in our prehistoric past is rarely discussed. Some speculate that this may be because emotions can appear to be rather too woolly and not scientific enough as an area of study. | suspect, however, that it is our own discomfort with the vulnerability that our emotions present that may have played a more significant role. A narrative of our past as one of invincibility, innate success and independence seems far more enticing than one that takes into account our social emotions and, with them, interdependence and vulnerabilities. We prefer to see ourselves as distinct from other animals because of our superior intelligence, our complex language or our toolmaking abilities, even though underneath these exterior qualities lie a complex human emotional world and a level of sensitivity that are far more remarkable.

FOREWORD xiii

Things may be changing. Global developments in recent years have highlighted existential threats, such as climate change, inequality and the COVID-19 pandemic. These threats prompt both an increasing sense of being united by our shared futures, and a questioning of who we are as a species. The pressing issues of climate change cast a new light on humans as part of a wider natural world that we cannot always control, and as being vulnerable to changes within it. The COVID-19 pandemic has prompted us to view both our interdependence and our emotional vulnerability in a new light. We have all felt differently about ourselves and other people around us. We have been moved to tears by deprivation or suffering - the pain and grief of illness, families who are hungry, people who are scared, those who lose loved ones or are lonely. We have also grown to appreciate much more fully the depth of our capacities to care for each other and the power of human emotional connection. We have been inspired by the sheer numbers of people working so hard or even risking their lives to make sure that people they have never met were safe and well. We have missed simple human contact and, from small acts of kindness to inspiring acts of altruism, have grown to respect our common humanity ever more. It will be hard to forget the power of human compassion or how vulnerable we are, as humans, to loneliness, a lack of connection or even for many the intense grief at the loss of loved ones. In the face of a changing climate, we are reminded of the roles that our biology and physiology play in our lives, and how intimately we are connected to our existence as animals, and part of nature.

Amidst all of this, our need to know why we feel the way we do, and how we preserve the best of our experience, has never been more pressing.

Only from the heart can you touch the sky.

Aims

We readily accept that it is our emotional connections to the people whom we love and care about that make us human. We sacrifice for our loved ones, feel joy and pain in equal measure with our friends, and even reach out to connect to the lives and wellbeing of people we have never met. However, we rarely think about where these feelings come from. Our stories of human evolutionary success are so focused on intelligence, individual resilience or strategic collaboration that you might even imagine that our ancestors had no significant emotional connections at all.

The aim of this volume is an ambitious one. We hope to begin to better understand the distant evolutionary origins of our peculiarly human social feelings and how they drive our emotional connections to those around us. We hope to untangle why we respond so readily to others in need, why kindness is so important, and why our rather peculiar emotional vulnerabilities and sensitivities emerged. In doing so, we also hope to better understand our own feelings and uncover why the evolutionary background to our human emotional connections is important today.

We will, of course, build on existing research. Most obviously, we will build on decades of research into understanding why human minds are unique.

Spikins, P., 2022. Hidden Depths: the origins of human connection. Pp. 1-13. York: White Rose University Press. DOI: https://doi.org/10.22599/HiddenDepths.a. License: CC BY-NC 4.0

These include approaches to the evolution of human intelligence in general, and to specific types of ‘intelligence’ (Overmann and Coolidge 2019; Overmann and Wynn 2019; Wynn and Coolidge 2016), including social intelligence (Dunbar 2003; Dunbar 2018). We will consider what we can learn from the emotional motivations of minds very different from our own, such as those of our nearest living relatives, chimpanzees, and those of our closest friends, dogs and their wolf ancestors. We will also build on a history of research into our emotions that began as far back as Darwin himself (Darwin 1872).

We will also expand existing research. Within archaeology, for example, aside from debates over evolutionary changes in emotional attitudes to death (Pettitt 2010; Pettitt 2018; Pettitt and Anderson 2019) or to childcare (Hrdy and Burkart 2020; Langley 2020), there has been only a limited body of research into how the archaeological record provides insight into the evolution of our modern social emotions or our close human emotional connections to others. Palaeolithic archaeology, in general, has tended to shy away from emotions, with discussions of how our minds evolved tending to focus on subjects such as thinking skills, the basis for art, or the origins of language (Coward 2016; Stade and Gamble 2019), or been limited to a cultural rather than evolutionary viewpoint (Lyons and Supernant 2020; Tarlow 2012). Evolutionary archaeology of those most human emotional capacities that affect our social lives is relatively novel. Furthermore, we hope to develop a wider interdisciplinary perspective on human origins, drawing on material evidence for real people and behaviours in the distant past.

We will bring something new. We are already aware that our human capacity for social collaboration was important in our distant evolutionary past. However, there is much more to discover about why our human emotional connections are such an important part of our evolutionary story. We need to delve into the specifics of archaeological and fossil evidence, as well as evolutionary understanding, to uncover what happened in our distant origins to make us capable of the emotional connections that bind us together today. Over the 7 to 8 million years of an evolutionary past that separates us from other apes, there have been many different ecological changes, selective pressures, evolutionary branches and offshoots, and many different societies and cultures with different types of social lives. It may be too much to expect to fully understand all we might wish to about the prehistoric past of our social emotions. However, we can at least hope to cast a far greater insight into the peoples and societies in the distant past that helps to explain why we feel the way that we do and, perhaps beyond this, we can hope to gain a fuller appreciation of why our emotions and emotional vulnerabilities are significant for the future.

We will also attempt to move away from traditional approaches to human evolutionary narratives (see Athreya et al. 2019; Porr and Matthews 2019). Specifically, we here move away from an idea of a ladder of progress (Athreya et al. 2019) and from the notion of humans as exceptional (Anderson 2019). We also seek to move beyond ideas of different variations of human as superior or inferior to each other, and from a focus on intelligence as some prime mover or defining feature of humanity (Anderson 2019). In doing so, we hope to piece together a new narrative of our origins that plays a more positive role in our modern worlds.

There are many avenues that have not been followed. There are voices, including those of indigenous populations, that have yet to be heard in our narratives of human origins (see Sterling 2015). Moreover, through the unfortunate ease of access to archaeological material and interpretations, we continue to rely most heavily on European material in discussions of the most recent periods of human evolution. There are new narratives around gender or sexuality in the past that remain to yet be told. Where we hope to progress in particular, however, is around a greater emphasis on narratives of physical and cognitive diversity, and in tackling the issue of different but equally valid ways of being human in both the past and the present (Wright, Spikins, and Pearson 2020).

Further, here we move away from concepts of a linear evolutionary progression to a more superior human form and, instead, move towards interpretations of evolutionary history in which there is no necessary single shared direction of movement, and in which a model of different evolutionary pathways connects more clearly with adaptations occurring in other social animals. This is a narrative in which the significance of our shared biology and how it connects us to nature is more clearly emphasised.

Challenges

Our emotional connections to people, and even other animals or things around us, are a challenge to research and understand, even more so in the distant past. They are, after all, some of the most inspiring, troubling and problematic elements of our uniquely human experience. The effects of our emotional connections are often intangible. Yet, we are so sensitive to how others feel that simply being with people who care about us makes us feel relaxed, safe and happy (Armstrong et al. 2021; Marsh 2019), and their care makes us healthier and more resilient to stress (Gilbert 2021). The feelings of those around us affect us so profoundly that emotions and motivations can cascade across our social networks (Fowler and Christakis 2010). Moreover, we are even affected emotionally by the wider economic and cultural systems in which we live (Becker, Hartwich, and Haslam 2021). As such, just as our emotional connections can elevate us, they can also bring us down or debilitate us. Whilst most of us discover our greatest joy and happiness in our relationships with others, our human emotional connections also mean that we can be disabled by grief and find it almost impossible to live without loved ones. We all too often find ourselves uniquely connected to another's suffering, crushed both emotionally and physically by cruelty or the wrong type of social connection, or debilitated by isolation or loneliness (Bzdok and Dunbar 2020; Gilbert 2021; Spreng et al. 2020). This emotional sensitivity seems hard to explain within a functional evolutionary framework, and is rarely acknowledged in broader society. Yet, far from a fault, it is also an essential part of human experience. Just living life as a human being, with the breadth of our emotional experience and all our emotional sensitivities and vulnerabilities, prompts us to question why we feel the way that we do, how far back these feelings go, and why they might even have been important for our survival.

We face a number of hurdles in building up a picture of the key developments in the complexity of human emotional connections. Firstly, we need to draw on the often-scanty material record left behind by our many different human relatives, a record that is not without constraints and issues. Secondly, we will need to navigate a challenging area of research lying between commonly accepted disciplines and, lastly and perhaps most importantly, to overcome our own assumptions and biases.

In bringing the material record to bear on the question of how our social emotions evolved, we will be disappointed if we expect some prehistoric Pompeii, or an obvious link between how people behaved and their emotional motivations. The further back we go in time, the less archaeological evidence is preserved, and the more difficult it becomes to interpret. Like fishing in ever deeper waters, further from the surface there is less to find and, what’s more, we often come across unusual things that we do not really expect. The archaeological record of the Palaeolithic, for example, only starts with the earliest stone tools around 3.5 million years ago, and most of our archaeological record is made up of these highly durable stone tools, with the fortunate addition of some fossilised animal or, occasionally, human bones. Evidence for things like art or mortuary practices, or even the full range of the types of resources that people were hunting, gathering and eating, are extremely rare, and are often surprising in form. Some of the earliest mortuary practices, for example, seem to involve depositing bodies in particular places, including caves. Quite why remains something of an enigma (Pettitt 2010). We can only look with a certain amount of jealousy at the often-predictable results, large sample sizes and statistical confidence seen in many other areas of science, such as modern psychological studies.

More than this, what we do find may not be easy to interpret. The archaeological record gives us, at best, an indication of how people behaved in the past. How they felt is something that we have to infer, and rarely is this ever with any confidence when we are dealing with single cases. What people do is influenced by far more than simply their emotional capacities. Rather than expecting to find evidence that tells us with any certainty how any single individual might have felt, we must look instead for changing patterns of behaviours and what that can tell us about how emotional capacities were evolving and emerging, much as we might take the same approach to other areas of cognitive evolution (Wynn and Coolidge 2016). As we shall see in Chapter 2, the archaeological record for recovery from illness and injury, demonstrating probable care from others, is a good example. We cannot possibly be sure that someone was not cared for through some calculating motivations on the part of someone else who might possibly have wanted them to survive some injury for their own selfish reasons. However, when we see a pattern of many cases of care consistently appearing across long periods of time we can begin to reasonably infer the importance of evolved emotional tendencies to respond to others distress. We have to build an understanding by focusing on the patterns that tell us about how emotional capacities may have changed, and leave what any one person in the past actually felt to speculation. Of course, we cannot help but imagine how any individual might have felt suffering some severe injury and being cared for by those around them in the most difficult of circumstances but, when it comes to making inferences about how emotional capacities evolved, we will be limited to considering the patterns of broad scale change.

There are other, perhaps even more important constraints on what evidence is available, and these, ironically, result from our evolved tendencies themselves. Because we have evolved to pay the greatest attention to the types of things which might present a danger to us - violence or conflict, for example - these elements of our distant past also attract the far greatest attention (Soroka, Fournier, and Nir 2019). Tilley commented, for example, that the main publications about a brain injury in the Saint-Césaire Neanderthal focus almost exclusively on how this injury may have been the product of interpersonal violence, with almost no reference to the weeks or months of survival from injury, which strongly suggests care from others (Tilley 2015). Most of us have an image of Neanderthals as being brutish, competitive and violent, even though, as we shall see in Chapter 8, the evidence for interpersonal violence is quite scanty (with very few relatively clear cases) compared to that for lengthy and extensive interpersonal care (Spikins et al. 2019). All too often, it is those scant examples of violence that attract the most attention, both academic and public. The often-overlooked archaeological evidence for caring, supportive or sensitive behaviours will take a certain amount of uncovering.

A natural negativity bias may have made sense in a far-distant evolutionary world, where being particularly alert to the dangers posed by any possible predator or dangerous situation was critical to survival. However, basing our understanding of who we are on our intuition about what the past ought to have been like is a risky business. Because of this bias, the behaviours of the small numbers of others who are callous or cruel most attract our attention and give us the impression of an innate aggressiveness to human nature despite most of us being remarkably altruistic (Marsh 2019). A mythical violent or selfish past can be part of the assumptions we make when we create societies that bring out our worst selves and do not cater for either the better, more caring and more tolerant part or natures, or our sensitivities.

The archaeological evidence is only half of the story. Without an understanding of the biological basis of how hormones influence our emotional motivations, and the cognitive or social psychology of behaviours set within an evolutionary context, none of what we might find makes sense. We will also have to draw on insights from many different disciplines if we are to understand the process through which our evolved emotional capacities emerged. We need to understand what happens in the mind of an early human as they perceive and respond to others’ suffering, how hormones and their evolutionary history influence what we do, what the evidence from fossil hominins means for the nature of changes, and the ways in which ecological circumstances drive species along different evolutionary branches. This type of interdisciplinary research is always challenging. As academics, we tend to be encouraged to stay within our disciplinary boundaries and become ever more specialised in a single area. The patterns and processes occurring in the past, from which our evolved emotional capacities emerged, did not happen in one neatly defined realm, however. From the biology of hormonal responses, to cognition, to ecological changes, social relationships and even cultures, we will have to have some grasp of all of these things to make sense of the evidence.

Perhaps the most significant challenge, however, comes from within - that of overcoming our own assumptions of and preferences for what the trajectory of our evolutionary past should look like. It is all too easy to write a pleasing narrative around the evolutionary past we want to believe in, whilst the actual history behind our emotional capacities may be far more useful to us.

Most obviously, we much prefer a success story. We almost always hear of human origins through a narrative of gradual progression towards a final form, ourselves, who we see as a kind of pinnacle of evolutionary success (Scott 2010). Indeed, the idea that evolution made us perfect, and that as a species we triumphed over adversity to become uniquely successful, is so hard baked into our culture that it can be hard to see past it. Surely, we reason, we must be better than any human species that came before us.

Not only in physical form, intelligence and technological capacity but also in emotional capacities. The ultimate success story. More advanced than any other on the planet.

Rather than a simple progression, there is abundant evidence for a much more complex story that speaks to us less of ‘success’ and more of a sequence of adaptations and changes, some more random than others. Recent years have demonstrated that human evolution is far more complex than we often assume, for example. We now know that there are many more species of human, existing in a complex relationship with each other, rather than any single evolutionary lineage (Galway-Witham, Cole, and Stringer 2019). More than this, evolutionary processes themselves are much more chaotic and undirected than we often assume. Different species simply adapted by responding to constraints and opportunities in ways that brought both advantages and disadvantages, but not intrinsically ‘better’ or perfect forms. Rather than any step being better, there were always compromises to be made. Human brain expansion facilitated great cognitive advancements, for example, but at the cost of high energy expenditures and risks in childbirth. Bipedalism may have freed up hands and brought certain energetic advantages, but imposed stresses on the spine. The same possibilities, constraints, advantages and disadvantages are true of how social emotions emerge. Shame or guilt may motivate more moral behaviour, for example, but can also come at a price. Shame, in particular, can have lasting negative effects on wellbeing (Longe et al. 2010). Moreover, certain changes or adaptations are often part and parcel of other developments, ‘hangers on’ in genetic terms, or simply made little difference. A simple story of evolution as a‘better’ form winning out over others, or anything being ‘perfectly evolved’ is more myth than reality. Only by understanding the complexity of branches and compromises can we move away from our perhaps rather colonially inspired narratives of superiority and inferiority, and of anatomically modern humans (henceforth ‘modern humans’), our own species, as naturally somehow exceptional. Even using the term ‘modern human’ for our own species is problematic, as it seems to imply a certain superiority. We may now be the only such surviving species but others to which this term could equally apply were our contemporaries for tens of thousands of years. There is, however, no better option that everyone understands.