The Sociological Significance of Non-human Sleep

Introduction

Although once operating in relative obscurity, the sociology of sleep has in recent years become a more legitimized and prominent area of study (Arber et al., 2012; Meadows, 2012; Williams et al., 2010). Sleep has become a more accepted object of sociological inquiry because of the growing recognition that sleep is not simply a biological phenomenon, since ‘how we sleep, when we sleep, where we sleep, what meanings we attribute to sleep, who we sleep with, are all … socially, culturally and historically variable matters’ (Williams, 2008: 640, emphasis in original).

Research in this rapidly expanding field has emphasized that sleep is ‘a rich and fascinating sociological topic in its own right’ (Williams et al., 2010: 275). For one thing, this is because sociological research can help to explain how and why people sleep in the ways that they do. What this stems from is the fact that sleep almost always occurs in a social context and therefore ‘to understand sleep or sleeping, […] we need to understand a good deal about people’s social lives, social roles and social relationships’ (Williams, 2005: 3). Sleep is also an important topic for sociology ‘in its own right’ because it problematizes some sociological assumptions about what social life consists of. The sociology of sleep reveals that there is more to social life than what simply occurs in the waking world, even though this has conventionally and previously been the ‘staple diet’ of most sociological research (Williams and Bendelow, 1998: 173). One of the reasons that sleep is consequential is because it affects our understanding of what it means to be a human subject and agent. Sleep and waking life are mutually informing realms of experience, so that what happens in one impacts upon the other. Accordingly, since sleep is not a wholly voluntary, consistent, or directly auditable act, this calls into question a view of human action that is exclusively intentional or conscious (Williams and Crossley, 2008).

While sleep ‘in its own right’ is a novel problem for sociology and the social sciences more broadly to confront, the sociological significance of sleep also stems from its capacity to act as a prism that can be used to expand and enrich our understanding of various aspects of the social world (Williams, 2005; Williams et al., 2010). There is a growing amount of research, for example, that investigates how gender relations are expressed and reproduced in and through people’s sleep lives (e.g. Hislop and Arber, 2003; Meadows et al., 2008; Venn, 2007). The study of sleep has also been used to mark shifts in the socio-temporal order (e.g. Hsu, 2014; Melbin, 1987; Williams, 2014). And moreover, sleep research has also served as a ‘valuable new window or way of approaching existing sociological research agendas’ on a multitude of other issues such as work, health, ageing and family life (Williams et al., 2010: 275).

Although the sociological study of sleep has become a more legitimate field of research, there are aspects of it, however, that remain embryonic. The aim of this article is to shed light on one of these aspects, which has to do with the way in which sleep has been defined and analysed in sociological circles. For the most part, the sociology of sleep has operated with an understanding of sleep that mainly frames it as a trait that only human beings possess. But of what benefit is it to think more expansively about sleep, so that the phenomenon is not exclusively associated with human beings? In this article, I seek to pursue such a line of theoretical inquiry.

One of the key arguments I wish to advance is that the sleep of non-human entities is also sociologically significant. I develop such an argument by first exploring why analysing the sleep of animals ¹ is fruitful from a sociological perspective. In the second part of this article, I discuss why it might be useful to understand sleep as a property ascribed to some technological objects, as a way of further illustrating the sociological significance of non-human sleep. Thirdly, I reflect on what it more broadly means to understand sleep in these expanded ways, especially for theoretical and empirical work associated with ‘the new materialism’. I conclude by exploring the new research pathways that the concept of non-human sleep opens up.

The Sleep of (Non-human) Animals

There are a number of reasons why it is beneficial to hold a more expansive sociological understanding of sleep, so that it is not only framed as a human attribute. The first has to do with the value of studying the sleep of non-human animals from a sociological perspective. What is problematic about studying humans in isolation is that this overlooks a key aspect of social life: the impact that animals have on human relations (e.g. Irvine, 2008; Sanders, 2003).

In order to gain a deeper sociological understanding of how humans and animals figure into each other’s lives in a multiplicity of ways, I propose that it is important to consider how sleep is found in many parts of the animal kingdom and not just in human beings. Why it is worth calling attention to this aspect of animal behaviour is because animals and human beings are not just involved in each other’s lives in the waking world alone. Sleep is also a realm of social life where humans and other species interact, which is why then the sleep of animals ought to be a greater object of sociological inquiry. If there is indeed a pressing need to expand our understanding of how animals and human beings relate in the social world, then it is fruitful to consider how the sleep of animals is not a purely biological phenomenon.

The sleep of animals is also a sociological matter because it is informed by and informing of human practices. This is evident in the way that human beings have the capacity to partly affect how sleep is organized and experienced for some animals in a variety of social contexts. For example, human pet-keepers commonly regulate which animals they will allow into their beds. While many kinds of animals are not typically allowed to sleep next to human beings in their private sleeping quarters, some pets such as cats and dogs by contrast are permitted to do so, as some recent reports suggest (see Thompson and Smith, 2014). At one level, why it is sociologically significant that some animals are allowed to sleep next to human beings is because analysing this practice might help to further elucidate the kind of close and intimate bonds that animals and humans can form with one another. This has to do with what it means in some social contexts to share a sleeping space. Since sleep has become more of a ‘privatized’ phenomenon in many parts of the contemporary Western world, as some sociological research has uncovered, the practice of sharing a bed has become more of an intimate act, which normally only takes place with family members or close relations who inspire a sufficient amount of trust (Taylor, 1993; Williams, 2007a). That human beings not only share sleeping spaces with other humans but with some kinds of animals as well can thus be used to indicate how some animals are counted as important and trustworthy members of people’s families, which may in turn also explain how pets are in some cases endowed with a sense of personhood (Fox, 2006; Sanders, 2003).

On the flipside, that some animals are never or only sometimes permitted to sleep in direct proximity with human beings is something that might be used to indicate how pets are also conversely treated at some level as intrinsically different creatures, on account of their ‘animalness’ (Fox, 2006). For instance, the medical discourse surrounding zoonoses, which refers to the inter-species transmission of diseases, commonly focuses on the dangers of bed-sharing with pets (e.g. Chomel and Sun, 2011). Within this discourse, there is a tendency to assert that even though some pets are regarded as friendly and supportive companions with human-like attributes, pets should not be always, or ever, allowed into people’s private sleeping quarters, since they still ought to be viewed as animals capable of carrying and transmitting disease. ²

The practice of co-sleeping with animals is also sociologically relevant because it potentially sheds new light on how human–animal relationships reflect and refract a myriad of social differences. What some research has recently explored, for example, is how gender partly shapes the ways in which humans and animals interact with one another (e.g. Herzog, 2007; Ramirez, 2006). One way to further investigate this link is to look at the extent to which men and women differ in their approaches to sharing a bed with a pet animal. Thus far, this is an issue which has remained understudied, since it is not yet known in most contexts whether bed-sharing with pets is more or less prominent for men or women, ³ nor is it well understood why such a possible discrepancy might exist. But if there are indeed gender-related differences in the way people approach the practice of sleeping next to a pet, then what this might further illuminate is how gender is expressed through the corporeality of human–animal relationships (e.g. Birke and Brandt, 2009). What constitutes acceptable forms of physical contact between animals and humans, as Rebekah Fox notes (2006: 533), tends to vary within society. If men and women tend to hold differing views about co-sleeping with pets, then this might further explain how gender is expressed in and through the ways that humans relate to animals at an embodied level.

Why the sleep of animals is sociologically significant is not only because it potentially sheds new light on how humans and animals relate to one another through the practice of pet-keeping but also because it helps to advance a more complex understanding of animals as being active participants in the social world. This relates to the growing recognition that animals should not be simply viewed as objects that stand passively in the background until they are ordered about by human action (e.g. Carter and Charles, 2013; Hobson, 2007; Pearson and Weismantel, 2010). Even though animals are to some extent acted upon, animals also themselves are social actors, capable of informing and/or disrupting how human beings live their lives. Considering how sleep factors into the animal world is one way to further such a theorization of animals.

This has to do with the fact that animals do not always sleep in ways that are conducive to the wishes and expectations of human beings. Some animals may have sleep/wake cycles that obstruct certain interactions with humans from taking place. For example, because some animals tend to be nocturnal or crepuscular, it is not normally possible for people to see these animals engaged in activities during the daytime, which is when most humans tend to be active and awake. The zoo is one place where this is especially evident. Although visitors commonly prefer to see ‘animals in action with other animals or with people’ instead of in a state of repose (Kreger and Mench, 1995: 147), this does not usually occur with nocturnal animals. For people to see nocturnal animals in an active state during the day, artificially lit environments need to be specially built to try to alter the kind of sleep/wake cycles that these animals are engaged in. However, it is important to recognize that not all of these attempts to change the sleep/wake cycles of various animals are always successful and there is a growing amount of research that indicates that the use of artificial lighting often leads to unforeseen outcomes and unexpected changes in behaviour (e.g. Longcore and Rich, 2004; Morgan and Tromburg, 2007: 268–270).

Moreover, when it comes to the practice of co-sleeping with pets, that some pets sometimes sleep in ‘disruptive’ ways is a phenomenon that further illustrates how animals are affective beings. For instance, pets such as dogs are known to wake up and make noise at unwelcome times, due to the fact that their sleep/wake patterns are structured quite differently to human beings (Adams and Johnson, 1994). Some canine species are also known to snore (e.g. Widdicombe and Davies, 1988) and to be affected by sleep pathologies such as narcolepsy (Mitler et al., 1974). Moreover, some animals are known to be more insistent than others in resisting human efforts to regulate where it is that they sleep, which in turn can affect interpersonal relationships (Thompson and Smith, 2014: 117–118). There is thus a sense in which animals, like humans, are capable of being ‘inconsiderate’, ‘anomic’, ‘anarchic’ and ‘deviant’ sleepers (Williams, 2007a: 321–324). And, accordingly, what this all speaks to is the way in which animals and humans engage in two-way relationships. While humans are able to exert much influence on how sleep takes place for animals, nevertheless animals still can sleep in unexpected, inconvenient and/or socially unsettling ways.

Technological Sleep

While it is possible through the prism of sleep to gain a more in-depth and multifaceted understanding of human–animal relations, there is also an opportunity to deepen what we know about how humans relate to technological devices if sleep is conceptualized more broadly. Another way to adopt a more expansive view of sleep so that it is not only framed as a property of human beings is to consider how some technological devices sleep.

Why there is a need to better understand how technological devices factor into the lives of human beings is because it is incorrect to think of social relations as ever being wholly independent of technology (Wajcman, 2002: 355). Instead of ‘being a sphere separate from society’, the ‘technological’, as Donald Mackenzie and Judy Wajcman assert, ‘is constitutive of society’, in that it is ‘part of what makes society possible’ (2002: 354).

In recent years, a growing body of work has developed to analyse how the advent and spread of some new kinds of technology inform the types of interactions that people have. In particular, much has been made about the arrival of new information communication and electronic media technologies, such as mobile phones and mobile computing devices (e.g. Campbell and Park, 2008; Elliott and Urry, 2010). In many of these accounts of mobile communication, what is commonly foregrounded is the way in which information and communications technology (ICT) and electronic media devices are socially significant because they act as conduits or ‘portals’ into certain kinds of social networks or virtual cultures.

However, according to David Beer (2012), this aspect of mobile media technology fails to encompass the multitude of ways that mobile and electronic media devices factor into people’s lives. This is because it is also important to investigate how people form material and emotional relationships with mobile devices themselves, which has not received as much sociological attention. One way to deepen understanding of how people materially relate to technological objects is to investigate how sleep is thought to be present in some forms of technology. The basis for suggesting that some technological devices sleep has to do with recent technological advances in the electronic world. Since at least the 1980s, ⁴ it has become increasingly more commonplace for electronic devices to come equipped with a ‘sleep mode’ function. When a piece of electronic equipment such as a computer or mobile phone is put to ‘sleep’, this typically means that the device has entered into a power-saving state after it has been left idle for a certain duration. Besides conserving energy, what is beneficial about having the sleep mode function on a device is that it allows – at least in principle – the device to be restored to its most recently active state at a faster speed than if it had been switched to the off position.

In recent years, the sleep mode function has become so ubiquitous ⁵ that it is now not unusual for people to remark that a technological device of theirs has ‘fallen asleep’ or has ‘woken up’. One reason why this practice is sociologically significant is because it relates to a growing body of sociological work which has found that technological artefacts are not merely perceived as tools or lifeless pieces of equipment, since some forms of technology are treated anthropomorphically as if they were social actors (e.g. Lupton, 1995; Prasad, 1995; Reeves and Nass, 1996; Turkle, 2005). Studies that have advanced such a theoretical account of technological objects have done so through a myriad of ways. Some research, for instance, has investigated how certain types of technological devices are comparable to persons because they are able to ‘flatter’ (Fogg and Nass, 1997) or ‘apologize’ (Tzeng, 2004) in a human-like manner.

Analysing how sleep is attributed to technological objects may similarly shed some new light on how people socially interact with the technologies that are present in their lives. This is the case if we consider how technological devices do not always sleep, as in ways that are anticipated or socially desirable. Electronics such as computers and smartphones, for example, are known to ‘wake up’ at inopportune times, which an increasing number of online articles have sought to address. Marvin Tobisch’s (2013) article in the PC Advisor, a popular UK online technology website, serves as a good case in point. Tobisch (2013) notes that even though there are benefits to putting your computer to ‘sleep’, doing so has a ‘major side effect’: ‘unexpected and unwanted boot-ups, often in the middle of the night’. Matt Smith’s (2014) article for the website www.makeuseof.com, uses even more descriptive language. Smith (2014) writes that ‘waking up in the middle of the night’ is ‘a problem that doesn’t just affect humans’, as ‘computers can have restless nights, too’. Smith’s and Tobisch’s articles ultimately share the same goal: to provide technical advice about what can be done to ensure that computers ‘sleep’ and ‘wake up’ as people would like them to.

Why there is a need to have control over the sleep and wake cycles of computers has partly to do with the fact that the timing of the sleep of technological devices affects how sleep takes place for people. Because some reports suggest that it may now be more commonplace for people to sleep in close proximity to the electronic devices they use (Hsu, 2014: 222–223), this means that people not only need to be concerned with how sleep is synchronized with other persons (Schwartz, 1970), but with some forms of technology as well.

However, having complete control over how electronic devices sleep is not always easily obtained. This is typified by Tobisch’s comment that ‘finding the cause [of random computer wake-ups] compares to searching for a needle in a haystack’ (2013). There are many possible reasons why an electronic device might sleep or wake up erratically and so it is not always easy to pinpoint and resolve the issue at hand. Consequently, this further illustrates why it is apt to conceptualize a ‘nonbiologic object’ such as a computer or a smartphone as an interactive and fully-fledged ‘social actor’ in certain circumstances (Owens, 2007). Through the prism of sleep, we can see how an electronic device is ‘capable of action that we can perceive as independent of direct human cause’ (Owens, 2007: 580, emphasis in original). And, in turn, this suggests that a more sophisticated way of theorizing technological objects emerges if these objects are endowed with a sense of material agency (e.g. Kaptelinin and Nardi, 2006), the performative capacity to act, as well as to be acted upon in the social world.

Besides expanding what we know about how people relate to technological objects, what is further revealing about technological sleep is that it may also tell us something about how sleep is more broadly framed in the contemporary era. This is because the sleep of technological devices does not just reflect but also refracts how sleep is conceptualized in the human world. Jonathan Crary (2013) makes this very point by suggesting that the ‘sleep mode’ function of technological objects signals a shift in how sleep is understood, which in turn reveals a change in how society is organized. According to Crary, what is alarming about the ‘machine-based designation of “sleep mode”’ – which ‘remakes the larger sense of sleep into simply a deferred or diminished condition of operationality and access’ – is that ‘it supercedes an off/on logic, so that nothing is ever fundamentally “off” and there is never an actual state of rest’ (2013: 13). For Crary, this technological recasting of sleep is consequential because it keenly illustrates how there is an ever-expanding drive to depreciate the non-productive qualities of human sleep, which indicates that contemporary social life is becoming increasingly more non-stop and hyperactive.

What Crary’s argument here thus attests to is the need to look beyond the boundaries of the human world in order to gain a more complex and in-depth understanding of how sleep can be defined and practiced. How sleep is thought to occur in humans is something that influences how the sleep of technological objects is conceptualized. But on the flipside, the way that sleep is expressed in the realm of technology can also to some degree inform how human sleep is socially framed. This then further indicates that sleep does not exclusively belong in the domain of human beings, as the meaning of sleep can derive from multiple sources.

Non-human Sleep and the ‘New Materialism’

In this article, I have suggested two ways of expanding how sleep is theorized in sociology, so that it is not just framed as a property that human beings possess. First, I have described why it is significant to recognize that humans alone are not the only ones in the animal kingdom to engage in sleep. Animal sleep matters because the lives of humans and animals do not merely intersect in the waking world. The second way of widening the definitional boundaries of sleep that I have suggested has to do with the attribution of sleep as a practice that some technological entities can engage in.

These ways of conceptualizing sleep are meant to contribute to new and productive lines of sociological inquiry. In particular, one area of social theory that stands to benefit from a more expansive sociological understanding of sleep is research associated with the ‘new materialism’, a label given to theoretical and empirical work across the social sciences that ‘does not privilege matter over meaning or culture over nature’ (Dolphijn and van der Tuin, 2012: 85). One of the main informing strands of the new materialism has been the conceptual framework of actor-network theory (ANT). A key insight of ANT is that humans are not the only ones who possess agency, since non-humans can also have it (e.g. Sayes, 2014). However, as numerous works within ANT have stressed, this does not mean that humans and non-humans are directly equivalent (Callon and Latour, 1992: 360–361). This is because ANT works with a theory of agency that is more multifaceted than some other sociological accounts. From an ANT perspective, agency does not strictly have to involve intentionality. Agency can also be non-intentional.

Expanding the act of sleep beyond the realm of human beings is one way to further understand how the agency of non-human social entities is expressed. In particular, it further reveals how agency for both humans and non-humans alike can lack intentionality. For humans, while there is a sense in which people ‘do’ sleep (Taylor, 1993), sleep is something that to varying degrees escapes our direct control (Williams, 2011). Sleep is not something we can directly initiate or audit, and also in some cases it involves non-voluntary action, such as when some people sleep-walk, sleep-talk or urinate while sleeping. Sleep thus ‘complicate[s] our picture of agency’ in the human realm (Williams and Crossley, 2008: 3) because it illustrates how individuals are divided subjects. Not being able to fall asleep is an instance of a person being at odds with himself or herself.

But the fact that sleep exists throughout many other parts of the animal kingdom also exposes the complexity of how animals exert agency. Sleep is a part of animal behaviour where agency is negotiated and contested. While asleep, animals like humans are vulnerable to the actions of those who are awake (Williams, 2007b) or to the movements of the surrounding environment. Hence, it might be said then that sleep is a part of animal behaviour that is at some level open to the impact of other social and natural entities.

However, it is equally the case that animals can express agency through their sleep. At some level, this may occur non-intentionally. For example, when a dog’s biological sleep architecture (Adams and Johnson, 1994) causes it to interrupt the sleep of a human pet-keeper, it is not immediately evident how this involves intentionality on account of the animal. But at some other level, animals can express agency through sleep with some degree of intentionally. Why it is apt to think this way about the agency of animals is because it should not simply be accepted that animals are wholly non-intentional beings, as some recent research has shown (Rakoczy, 2008). Intentionality is a complex concept. In some formulations, a case can be made that animals can be intentional in how they act. This is evident through the prism of sleep. Some animals seem to prefer certain sleep arrangements over others and this conflicts with – and in some instances even overrides – the preferences of other persons or other animals (Thompson and Smith, 2014). Extending sleep beyond the realm of the human thus allows us to understand how animals, like humans, express agency in a number of ways. Animals live ‘complex social lives’ (Rakoczy, 2008) and investigating how animals sleep is one way to capture this complexity.

Attributing sleep to technological devices also has the potential to further other strands of research within the new materialism. In particular, it may be able to open new theoretical and empirical pathways in the field of Science and Technology Studies (STS), which has helped to develop many new materialist insights. In order to grasp this link, John Law’s (2010) account of how STS has theorized materiality is instructive to consider. Law finds that STS has approached the issue of materiality in two key ways. The first, which revolves around the social construction of technology, has sought to explain why technologies take on certain material forms using social factors (Law, 2010: 175–176). This well-established approach within STS has generated valuable insight into the sociological dimensions of how various technologies are materially produced, transformed and culturally adopted. Yet, one of the limitations of this approach, according to Law, has been its ‘commitment to theoretical humanism’ (Law, 2010: 176). It has tended to presume a relative level of stability in the natural and social worlds and that people are endowed with certain creative abilities.

By contrast, the second approach in STS, which Law describes as ‘material semiotics’, does not adhere to such assumptions. It significantly departs from the first approach in that it avoids taking the status of people and the natural world for granted (Law, 2010: 176). Rather, the material semiotics approach is more fundamentally, at its core, relational. It regards ‘natural, social, and human materials and realities’ as ‘effects rather than causes’, which ‘are in need of explanation’ instead of being able to explain anything in and of themselves (Law, 2010: 178–179). Material semiotics thus encourages STS to think more complexly about the matter of materiality. It does so by employing a unique analytical vocabulary. As Law explains, the emphasis of material semiotics is more on ‘verbs’ rather than ‘nouns’ (2010: 187). Law cites the work of Bruno Latour to illustrate one of the broad aims of the material semiotic approach, which is ‘to explore “the whole collection of verbs and adjectives, tools and instruments, which together define the ways of being real”’ (Law, 2010: 180).

The concept of technological sleep can be regarded as being part of this project, in that it is a verb which is involved in the formation of realities. Investigating how sleep is expressed in technological objects is illuminating because it reveals not only what technologies are but also what they can do. Technologies are multifaceted. Some can operate in different modalities. Sleep is one of many ways technologies can affect others and their material surroundings. This fact may be especially relevant for the study of social robotics. According to many proponents of this area of study, there is a pressing need to investigate how people relate to forms of technology, such as robots, that represent new kinds of beings (Shaw-Garlock, 2011; Zhao, 2006). These are technologies that blur the human/machine distinction. They can become involved in interpersonal relationships (von Scheve, 2014) and they can exhibit biological characteristics (Thrift, 2004). Sleep is an activity that some of these kinds of technology can engage in. ⁶ Future empirical studies of how sleep is expressed in technological beings will likely be able to signal the extent to which the biological is being interwoven into the design of newly developed technologies. Additionally, studies on technological sleep can generate insight into the various types of relationships these technological beings are having with humans.

The concept of technological sleep also contributes to the material semiotics approach in STS by illustrating how social order ‘is an effect generated by heterogeneous means’ (Law, 1992: 382, emphasis in original). This has to do with the observation that the social patterning of sleep is a highly coordinated practice (e.g. Schwarz, 1970; Williams, 2007b). In order for sleep to be achieved, sustained or interrupted in the human world, there needs to be confluence of promoting factors. For example, not only does there need to be a viable physical environment (such as a place with acceptable temperatures and levels of noise and light), suitable social and psychological conditions, among other factors, are also needed. The concept of technological sleep highlights how this relational characteristic applies to the technological world as well. The achievement, continuation and suspension of sleep in the technological world cannot be taken for granted, as they are dependent on a number of factors that may shift over time and are not reducible to the human realm. For example, a technological device such as a computer may be prevented from remaining in a sleep state because of detected movement caused by any number of changes in the social and natural world (e.g. an unexpected power outage; spread of a computer virus or faulty software update; an intentional or unintentional physical change in the environment). This reveals how technological sleep, like human sleep, should be thought of as an achievement instead of as innate property. And accordingly, it speaks to the analytical value of studying technological sleep from a material semiotics perspective.

Conclusion: Beyond the Boundaries of the Waking World

As a rapidly growing amount of sociological work has shown, it is worthwhile to undertake research that extends beyond the confines of the waking world (Arber et al., 2012; Meadows, 2012; Williams et al., 2010). I have sought to contribute to this emerging area of study by theorizing sleep more expansively so that it is not only attributed to human beings. Non-human sleep, as I have suggested, also matters sociologically. This is evident in the sleep practices of animals, which are consequential to the lives of humans and vice versa. In some circumstances, animal sleep can be the object of human regulation and intervention, especially in terms of where sleep takes place. But animals also can sleep in socially unsettling and disruptive ways, which further indicates that animals are not entirely passive objects to be ordered about.

I have also articulated how sleep is an activity that some technological objects engage in. Studying how sleep is expressed in technological devices can be one way to deepen what we know about how people materially and emotionally relate to various forms of technology. Some technologies such as computers and smartphones, which are commonly present in the sleep spaces of humans, do not always sleep or wake up as anticipated. And, hence, this is indicative of the situational agency they can exert and the impact that they can have on people’s lives. Another reason to investigate how sleep factors into the technological realm is because it can inform how sleep is construed in other domains.

In the previous section, I suggested that these expanded ways of understanding sleep are particularly relevant to lines of research in the new materialism. This is because the concept of non-human sleep helps us to capture the complexities of how animals and technologies materially act in the social world. Future studies of animal sleep may further reveal how the agency of animals is expressed in a number of different ways. Likewise, there is also benefit in investigating how sleep is expressed in technological devices. Doing so may illuminate how the boundary between humans and machines is becoming blurred and how biologic features are being materially inscribed in the technological world, as some accounts have noted (Thrift, 2004).

To be sure, these reflections about the sociological significance of non-human sleep should be regarded as introductory ones. They are meant to spur on new lines of empirical and theoretical research within the sociology of sleep and across the discipline more broadly. ⁷ But there are still a number of important items worthy of further consideration, which this article did not have the space to cover.

One of these items concerns how the study of non-human sleep involves a number of methodological challenges. As Simon Williams et al. (2010: 277) describe, researchers in the sociology of sleep have not only had to shift how sleep is conceptualized. They have also had to refine existing research methods or develop new ones to capture how sleep is expressed in the social world. Future sociological work should investigate how this is the case for the topic of non-human sleep. For example, it may be worthwhile to consider how investigating the sleep of animals shifts the place and context of sleep research. Thus far, studies of the sleep-related behaviours of animals have tended to rely on objective measures and be based in laboratory settings. ⁸ What a heightened sociological interest in animal sleep may lead to is a greater emphasis on other sleep spaces that are not as clinically designed (e.g. Thompson and Smith, 2014). A further related methodological issue is how to track and define the sleep of non-humans, given that measuring the sleep of humans is not such a straightforward task (Williams, 2014).

Another future direction to explore, concerns the ethics of undertaking research on the sleep of non-human entities. In many parts of the contemporary Western world, there is the view that ‘sleep may be thought of and defended or championed as a basic human right’ (Williams, 2011: 56). Insofar as the systematic denial of sleep might be thought of as a form of torture or abuse in some circumstances, then it may be appropriate to ask if the acute withholding of sleep in animals, especially in laboratory settings, is an ethically justifiable practice? In the technological realm, it may be worth asking from an ethical point of view not only how sleep is practiced by new forms of technology but whether this feature ought to be built into certain types of technologies. This line of inquiry might pursue research questions such as what the dangers are of designing robots that do not sleep, especially in the context of warfare or finance. Do sleepless robots decrease the amount of autonomy or control that people feel they have? What are the social benefits of producing technologies that have a sleep function?

These and other potential lines of inquiry that I have discussed in this article are meant to indicate how fertile the sociological study of non-human sleep can be. By framing the concept of non-human sleep as a valid object of sociological research, I have sought to further Simon Williams’s view that sleep ‘is a complex, multifaceted, multidimensional phenomenon which cannot be reduced to any one domain or discourse’ (2005: 169). Williams has described how this is so for the ‘biological, psychological, social or cultural’ (2005: 169). But I have sought to reveal how sleep also cannot be reduced to the human.