Nature and Natural Rhythm in the Digital World - What's in It for Child–Computer Interaction?: A narrative literature review and an initial design framework

Nature and the natural world are important for the well-being of humans, a position that has been acknowledged in research within various disciplines. Research has also shown humans are alienated from nature, which is of great concern, especially for children, whose well-being should be society's top priority. Child–computer interaction (CCI) research is among the disciplines that should examine nature and natural rhythm in children's lives from the perspective of digital technology. We build a multidisciplinary theoretical framework on nature and natural rhythm with which to review the extant CCI literature. We discuss the state of the art and identify paths for future work. We show that in CCI research, being in nature and catering to nature have been addressed, while less attention has been paid to children being part of nature and its natural rhythm. We discuss how CCI research and design can acknowledge and better support such aspects.


INTRODUCTION
Children today are living digital lives.Digitalization-novel digital technologies and materials-has augmented nearly every aspect of humans' daily lives.This change, the long-term consequences of which are still unclear, is historically and culturally revolutionary [22,24], [104].Digitalization is no longer just a tool; it's intermingled with our humanness [36].The change in the everyday presence of the digital world has not gone unnoticed in research.While the digital world opens new opportunities, it also may isolate individuals and prevent intimate contact among them [86].The prevalence of the digital component in children's lives has prompted concerns for their well-being [11].The literature acknowledges this duality of the impact of digitalization: it can strongly support children's wellbeing but can also hinder or destroy it, for example, with powerful addictions [11], [126].
One concern within the well-being discourse is humans' relationship with nature.Humans are natural beings and, thus, part of nature.Nature contributes to the well-being of humans in several ways [15,42,47,56,99,100] .However, humans have been alienated from nature: many children today are poorly connected to nature, presenting a challenge for the future of nature conservation [50].Due to urbanization, many children grow up without an understanding of nature and the intrinsic value of its existence and preservation; all this is followed by a sharp decline in ecological literacy and the emergence, even, of "biophobia" among children [28], [27], as people's routines and technologies increasingly disconnect them from natural surroundings [111].Such alienation cannot be blamed on digitalization alone; industrialization had already extensively contributed to this phenomenon [103].Then again, during the past century, digitalization has progressed extremely quickly, and in a sense, humans have, in an eyeblink, become distant from many traditions, including their close relationship with nature.Yet, the digitalized human and world are part of nature, too.We can ignore this aspect of the digital world, or we can exploit and better support it by letting nature guide the design of the digital future.
In this study, we focus on humans' relationship with nature and with natural rhythm, based on the assumption that nature is living, and all living things are rhythmic [123]; that is, all organisms are in rhythmic motion, seen, for example, in the human heartbeat and respiration [66] .Digitalization is alienating humans from nature and its rhythmic movement: Referring to heartbeat, Matthews et al. [78] maintained that the advent of digital technology and the resultant always-on ethos can disrupt the rhythms of individuals and of society in general and Chapman [19] described the alienation from breathing of a Western individual who suffered from emotional constipation, in addition to overcrowding and noise pollution.
This study addresses children's relationship with nature and natural rhythm.Children are ever more extensively being acculturated into the digital world, making an examination of their alienation from nature and natural rhythm critical.We contribute to child-computer interaction (CCI) research: Although children's relationship with nature and natural rhythm has received scholarly attention in CCI (e.g., [15], [27], [111], [21]- [24]), more extensive research is needed.Our study is guided by the following research questions: "How has existing CCI research addressed nature and the natural rhythm?How can they be addressed in the future?"To answer the research questions, we utilize a narrative literature review method, which suits topics that do not have established terminology, in which case much researcher interpretation and iteration is needed within a creative process that relies on the "researcher's insight and contextually sensitive judgment of studies' relevance and contribution" [12].To be able to find relevant studies and to make sense of the literature found, we first put significant effort into building a multidisciplinary theoretical framework on nature and natural rhythm: what they entail.To capture significant developments in the computing and design fields related to nature and natural rhythm, we also carefully examined relevant developments within Human Computer Interaction (HCI) research, inspired by the framework built on nature and natural rhythm.Only after these two inquiries, we were able to finalize the searches on CCI in premier CCI publication forums in the ACM Digital Library.Later, we included additional keywords, and thus followed a highly iterative search process.
We consider the theoretical framework we present as a valuable contribution to the CCI literature as itself, while the most significant contribution comes as a result of our analysis of the CCI literature, in which we identify developments in CCI as well as a number of fascinating and critical paths for future work, which we capture in an initial design framework for CCI research.The framework should guide and inspire CCI research to advocate children's being part of nature and its natural rhythm in the context of design and digital technology.
The paper is structured as follows.Sections two and three present our theoretical framework, which allows us to make sense of the CCI literature: section two presents the multidisciplinary basis for approaching nature and natural rhythm, and section three highlights notable developments in HCI research, showing the computing and design take on nature and natural rhythm.Section four introduces the literature review methodology we followed for deriving and analyzing the relevant CCI literature.Section five presents our analysis results, while section six discusses the contributions, implications, and limitations of the study and concludes the paper.

MULTIDISCIPLINARY BASIS TO APPROACH NATURE AND NATURAL RHYTHM 2.1 Humans as part of nature
This section underscores the significance of nature for us, and particularly for children, before moving to discuss the significance of natural rhythm.Nature has special significance in all cultures and civilizations.Humans and nations operate within the rhythm of nature [87], and the vital functions of the individual take place according to these rhythms.Nature dominates or shapes nearly all life circumstances.The concepts "Mother Nature" and "Mother Earth" have been used globally over centuries, [101], [110], [118], [131].Through the ages, nature has been treated as a fertile mother figure who cares for individuals.People have lived for millions of years in harmony with nature.Their ancient philosophy of respect for Mother Earth and for all life forms on the planet helps Western society reach sustainability and overcome crises that science and technology cannot solve [131].
Children are a group that is said to have a close relationship with nature, unless something alienates them from it.That connection is developed through repeated engagement with nature [50].Studies on nature experiences show that immersing children in nature for play and learning can reduce stress, improve brain development and recovery, increase social and emotional skill development, and enhance civic engagement at the individual level [15], [121].People feel like part of something bigger than themselves when they spend time in nature, where they may reach a state described as enchantment and detachment from everyday life [56], a conscious presence [47,100], and self-acceptance [99].Connection with nature is also described using the concepts of fitness and harmony [56], deeper awareness , and deep reflection [16].However, research that measures nature experiences and relationships with the environment also reveals negative experiences and the difficulty of breaking away from everyday life [100].A balance in the human-nature relationship is desirable because the two elements have been intertwined through of evolution e.g.[98].However, over the past three decades, access to nature has diminished slowly and subtly, and as a result, many children are losing that deep connection to nature [16,42].Understanding the relationship and connections to nature formed (or not formed) in childhood is important both for research and for the work done to support the well-being of children [16].

Natural rhythm
In this study, we focus particularly on natural rhythm, for which we underscore the fact that rhythm is a universal phenomenon in nature and in physiological activity.Already in the end of 1900s Bolton in journal of psychology [14] maintained that natural phenomena generally, if not universally, take a rhythmic form.According to him, a continuously ongoing recurrence of a certain phenomenon can be found in all that pertains to nature.However, being more philosophical in his approach, sociologist and urbanist philosopher Lefebvre [66] offered a more complex and interactive definition: "Everywhere where there is interaction between a place, a time, and an expenditure of energy, there is a rhythm." According to the author, this rhythm "identifies repetition of movements and action, the particular entanglements of linear and cyclical rhythms and phases of growth and decline." In the context of physical education, Maura [79] stated that "any alternate unfolding of a phenomenon or process is called rhythm."In the natural rhythms concerning the human body, special attention should be paid to cyclic and linear dimension.According to Lefebvre [66], the cyclical rhythm is based on the rhythms of nature and repeated cycles, such as the cycle of the year and the day and the cosmic states of tidal fluctuations, while linear, segment-like repetition arises primarily from people's activities, schedules, and social agreements: these two rhythms intertwine in people's everyday lives.Edensor [33] elaborated Lefebvre's ideas by examining the context of urban environments.He divided rhythms into human rhythms, body rhythms, traffic rhythms, and nonhuman rhythms.Based on these definitions and views, the focus of our study is on the regularly occurring repetitive rhythm in nature surrounding us, which seems to have an evolving, interactive dimension and a cyclic, transformative character.Moreover, natural rhythm in this study includes the rhythm close to us, the rhythm of human, which in addition to cosmic When considering the primitive and basic rhythm of human we are used to follow the surrounding natural rhythms, but from which we have become alienated in many ways with the advent of digitalization.Next, we discuss the variety we associate with the natural rhythm.
Nonhuman rhythms.According to Edensor [33], nonhuman rhythms include natural rhythms from the microcosm to the macrocosm, such as the intermingling of plants and the cycles of the seasons.At the broadest point, rhythms appear in the macrocosm environment.Cosmic rhythms are the most fundamental and important of natural phenomena.In the background, they trigger many other rhythms in plant and animal life.The most striking rhythm of the cosmos (see Fig. 1:1) is the regular alternation between light and darkness (Fig. 1:2) due to the rotation of the Earth upon its axis that constitutes a defined unit of time (i.e., a day).This alteration specially brings out the polarity of that natural rhythm.Days are grouped into months by the revolution of the moon around the Earth (Fig 1:3) and into years by the revolution of the Earth around the sun (Fig 1:4) [14].
Biological rhythms (bioperiodicities).The transformational character of the day and year cycle is emerging through natural changes that manifest through biological rhythms (Fig. 2), which, as general expressions of living matter, have been the foci of study for many scientists [61,79,85], [109].Multiple rhythms that govern human bodies have been identified, including ultradian rhythms, which represent a period shorter than a day but longer than an hour; circadian rhythms, which repeat roughly every 24 hours, regulating the sleep-wake cycle; and infradian rhythms, which reflect periods longer than the period of a circadian rhythm or a frequency of more than 1 cycle in 24 hours.One can also identify a circannual rhythm, which represents a biological process that occurs in living creatures over a period of approximately one year, and a diurnal rhythm, which represents any pattern that recurs every 24 hours as a result of 1 full rotation of the planet Earth around its axis.In addition to ultradian, circadian, circannual and diurnal rhythm there is as well seasonality, which is "a systematic periodic occurrence of events over the course of a year." Body and human rhythms.Medicine and natural sciences, especially biology, are familiar with the rhythms of the human body (Fig. 3), of which the most obvious and noticeable is the rhythm of breathing.These rhythms are called biorhythms because they refer to rhythms in living matter anywhere in nature [79].Various definitions of breathing accentuate the to and fro movement between some type of polar actions (inhale-exhale, obtain-release, exchange): the medical definition emphasizes inhale and exhale and the exchange of oxygen and carbon dioxide, the physiological definition addresses the exchange of oxygen and carbon dioxide with the environment, and the biochemical definition concentrates on combining oxygen and glucose, resulting in the release of carbon dioxide, water, and adenosine triphosphate [13], [117], [116].In addition to breathing, another life-sustaining rhythm in living nature is the heartbeat.Lefebvre [66] added hunger and thirst to the list of everyday body rhythms.The body is also full of other organs that function according to their own rhythms that occur in repeating episodes.In addition to breathing and heartbeat: "biology is dominated by rhythms, [such as] blood stream, brain activity (the rhythms of the bio-currents sent out by the brain, the sleepwake interchange), the liver activity, the activity of the stomach and that of the intestines, the activity of the excretory apparatus, as well as that of the tissues, metabolism, endocrine secretion, blood composition, etc. " [79].
Distinguishing human rhythms from body rhythms.Edensor [33] used the concept of human rhythms when describing sequences related to people moving from one place to another.These rhythms are not actually natural patterns, but they are closely connected to biological rhythms with habitual and repetitive qualities.Lefebvre [10] and many of his later followers e.g., [66,77], [122], [132] emphasized a natural perspective on human rhythms as a way of living and being.They developed a "rhythm analysis, " in which the body constitutes as a starting point.An important element to recognize is the way the senses connect to outer events."The rhythmanalyst is directing her senses towards movements among people and in nature."When listening to the environment, the rhythmanalyst "draws on his breathing, the circulation of his blood, the beatings of his heart and the delivery of his speech" [66,77].Rhythm analysts have the qualities of multidimensional listeners, listening through the body and interpreting different rhythms around them.According to Lefebvre [66], different cyclic and linear rhythms are connected and mutually interact, which can be called 1) polyrhythmia, which is the simultaneity of many different rhythms crossing each other; 2) eurythmy, or the balance and symbiosis of rhythms, or 3) arrhythmia, the disruption of rhythm or breakdown of synchronization.Those concepts are linked to health, as "eurythmy" means "healing" and "arrhytmia" means "pathological."Arrhythmia, especially, causes friction and indicates problems both in the functions of the human body and in the natural environment.

HCI RESEARCH ON NATURE AND RHYTHM
We inquired how nature and the natural rhythm have been addressed in HCI research to inform CCI research on how design and computing relate to these topics.We found novel perspectives particularly for addressing natural rhythm.Generally, HCI research has acknowledged the importance of nature: plenty of HCI studies have focused on digitally supporting human interactions in and with nature (e.g.[9,25,29,38,41,62,70,99,102], for a review, see [114]).A prominent stream of research, sustainable HCI, emphasizes the responsibility of humans to cater to nature, considering digital means and tools for accomplishing this objective [25,70,72].Interestingly, we could also locate some HCI literature addressing the natural rhythm in different senses.

Biological rhythms
In HCI research, biological rhythms have been acknowledged to play a remarkable role in human life.Through cooperation with life and medical sciences, the governing rhythms of the body have been identified in HCI research.Considering these rhythms can develop our understanding of the living relation between humans and technology, as biological rhythms enable living organisms to adapt and live with periodical environmental changes, such as variations in the relative position of the Earth and the sun [78].
In addition to identifying these rhythms, HCI research has recognized the meaning of these rhythms, which have a substantial impact on human feelings, thoughts, and actions.Like Matthews et al. [78] indicated, these rhythms are profoundly important for health, quality of sleep, and mood.The rhythms can be measured with the help of biometrics [27], which produce feedback called biofeedback (e.g., [37]).Measurements, however, are not the only approach followed in HCI studies.Researchers have contemplated on many ways by which the "HCI can complement our biological rhythms" [78].
The most meaningful and studied biological rhythm is the circadian rhythm, which refers to any biological cycle that follows a roughly 24-hour period, including regular changes in blood pressure and in cortisol and melatonin levels [78].Through circadian rhythms, humans have an inherent relationship with light and darkness [120].Like Matthews et al. [78] described, a circadian clock helps people synchronize with the solar cycle.Several studies have examined the circadian rhythm in HCI.Pusateri et al. [95] investigated design challenges concerning sleep games, Steiner et al. [115] considered the circadian rhythm of a plant in an experiment, and Kaur et al. [57] and Pusateri et al. [95] focused on monitoring the circadian rhythm.Often, when studying the circadian rhythm, the research concentrates on sleep rhythms [73].Pusateri et al. [95] and Kaur et al. [57] both mentioned this when examining breaks and transitions at work.Choe et al. [23] identified several design considerations, challenges, and opportunities for using computing to support healthy sleep behaviors.Monitoring alertness across the day, Tag et al. [121] recorded eye movements over the course of two weeks in the wild and built a robust model of diurnal alertness changes, referring to the circadian rhythm as well.
Some HCI studies also refer to the ultradian, infradian, circannual, and longer rhythms.As mentioned, ultradian rhythms are shorter than circadian rhythms.Kaur et al. [57] described systems that manage transitions within work life, breaks, and interruptions at work.People rhythmically take breaks due to internal fatigue, boredom, or hunger [57] that help to break free from ubiquitous and invasive technology.Accordingly, Peters et al. [92] considered challenges to and possible interventions for maintaining a healthy work-life balance for HCI researchers and professionals.In terms of infradian, circannual, and longer rhythms, HCI research has studied longer term life events and changes.Herron et al. [43] highlighted life-changing events, such as gender shifts, domestic violence, ending a romantic relationship, grief, and even genocide, and grouped them as "sensitive life experiences."Massimi [76] specifically emphasized the endpoints of life (birth and death) but also human growth throughout life.As Massimi [76] observed, we must also begin to consider how we can create personal technologies that gracefully grow-and die-with us.

Body rhythms
In addition to biological rhythms, the human body has become a key element in HCI research.HCI design has focused experiments closer and closer to the body, even going inside the body.Biofeedback [37] can be used to represent vital human functions.The most important vital functions in HCI are breathing and heart rate/beat.In any modality (visual, audio, or haptic) vital functions like breathing that can be observed help to perceive the rhythm of organs and their functionalities.In several studies, the normalized breathing signal is described in two parts, such as 0 = no air in the chest, and 1 = chest fully inflated (e.g., [37]) Breathing is supported in many ways.In their study of digital breathing support games, Patibanda et al. [91] underscored that regular breathing exercises can be a beneficial part of a healthy life, but the design of breathing exercise games is not well understood.Miri et al. [81] focused on the rhythmic regulation of respiration and demonstrated the effectiveness of a personal respirator in reducing anxiety.In their study on deep pressure therapy, Jung et al. [55] constructed respiratory models with the goal of representing rhythmic release and rhythmic flow.
Breathing and heart rate are monitored objects that are observed in many ways.Adib and colleagues [1] envisioned that a designed technology would enable smart homes to monitor people's vital signs, such as monitoring chest movements due to inhaling and exhaling and skin vibrations due to heartbeats, without the aid of body instrumentation, to actively contribute to the inhabitants' well-being.Aslan et al. [7] presented two tangible somaesthetic design examples: a real heart that allowed users to experience their own heart's behavior by providing haptic feedback, and a stuffed animal that could breathe in synchrony with the user.Lehmann and Buschek [67] reported on an in-depth study of electrocardiogram (ECG) biometrics in everyday life.
Rhythms not only act individually but also adapt to each other.As Lehmann and Buschek [67] indicated based on their study, for example, heart rate variability adapted to respiration as well as to circadian rhythms.In general, studies have contributed to the bigger picture that increasingly biometric modalities are viable for measurements in daily life (e.g., [67]).

Approaches concerning natural rhythm
When discussing the rhythm of nature in HCI research, the body serves as a starting point, as Tabor et al. [120] stated.For concentrating on the body, the HCI community has shown increasingly interested in approaches such embodied, inbodied and circumbodied interaction as well as somesthetic design that bear some relevance for acknowledging natural rhythm in HCI as well as do rhythm analysis in HCI and entanglement HCI.
Embodied interaction.Embodied interaction has been widely discussed and applied in HCI."Embodiment is the property of our engagement with the world that allows us to make it meaningful" [32].Embodied interaction is an approach to understanding humancomputer interactions that seeks to investigate and support the complex interplay of mind, body, and environment in interaction [5].This body-centered form of interaction has been recognized as urgent and necessary in all areas of life.The multidimensional interconnectedness and the body's crucial role when managing the rhythms of life have been acknowledged [123].
Inbodied Interaction.Inbodied interaction is a more recent development with a step beyond embodiment.It focuses on using knowledge of the body's internal systems and processes to better inform embodied and circumbodied design spaces, with its challenge being the obtainment of appropriate information about how the body itself works and how the body's different systems interact dynamically and, thus, rhythmically [2].This is a specifically HCI-oriented approach to the human anatomy and physiology that moves concretely closer to the body via innovative core concepts and models.Studies of externally embodied tools have moved inside the body.As Schraefel [105] accentuated, this approach will help researchers to consider how, by learning and applying these inbodied processes, we can open our design space for supporting human performance and quality for all, at scale [105].Through inbodied interaction, HCI research can gain functional access to the key internal processes that affect human health and well-being (e.g., [120]).One of the demonstrated models is called "in5, " the model of five fundamental-to-life processes: move, eat, engage, cogitate, and sleep.Researchers have investigated how these processes engage and integrate with the 11 organ systems [105].Rhythmic thinking is strengthened by viewing each inbodied system as following a clock.Like Murnane [84] asserted, cellular clocks interact with each other and are orchestrated by the suprachiasmatic nucleus, or SCN: the master clock (in the human brain) that creates an auto-regulatory 24-hour feedback loop, in accordance with the Earth's daily darklight cycle.These rhythms are, therefore, referred to as circadian rhythms.
Circumbodied Interaction.Circumbodied-around the bodyis a term coined in the context of inbodied interactions, with which the number of rhythmic relations increases, as the term refers to processes that are both external to the body and inbodied at the same time.They affect every cell in the human body and the metabolism within them [105].Circumbodied interaction brings to light the rhythmic interaction described by Costello [75] between cyclical and linear as well as between human and nonhuman.Like Andres and colleagues [2] pointed out, while embodied frames the body as the key mediator of human interactions with the world, and inbodied focuses on the specifics of the internal processes to enable and affect the state of that embodiment, circumbodied asks for reflections on the boundary of inbodied and embodied.More particularly, it asks what is not inside [2].The circumbodied (Fourth body/C4 circumbodied) includes air, light, gravity, and microbiome [84,105] with the ambitious goal of seeking information as directly as possible.
Somaesthetic Design.Somaesthetic design centers on designing with, through, and for the unified body/mind and its experience (the soma) [7,75]).The fundamental point of the somaesthetic design is that humans are in the world, acting in the social and physical environment with their bodies, not separate from them [46].Somaesthetic design concentrates on the body, particularly on body consciousness in aesthetic experiences, from the first-person perspective [106].Like Höök et al. [46] stressed, this design appreciation encourages and spurs bodily inquiry through interaction modalities, which require an intimate correspondence-feedback and interactions that follow the rhythm of the body."When Somaesthetic design speaks of rhythm and its processes, it is from the position of the moving, experiencing, lived body.Designs are seen as potentially creating an intimacy of rhythmic synchronicity that enhances human lives.This is an expression of one of the core ideals of Somaesthetic design, the aim to 'design for living better lives"' [75].As Höök et al. [50] described, somesthetic design models entail a distinct manner of making space by shutting out the outside world-metaphorically and literally.They rely on the articulation of bodily experiences to encourage learning and increased somatic awareness.Aslan and colleagues [7] provided two concrete somesthetic design examples: the real heart providing haptic feedback for users and the stuffed animal breathing in synchrony with the user.
Entanglement HCI.Entanglement is a concept that describes how humans and technology are increasingly intertwined and how technology has become part of our lives.It suggests that humans and technology have become intertwined in a way that changes our relationship and how we understand being human.Entanglement theories explore the complex relationship between humans and technology and how our use of digital tools and technology shapes who we are.They provide a framework for understanding the complex socio-material world.These theories suggest that our relationship with technology is more than just human-computer interaction, but instead a complex configuration that includes a nonhuman dimension [36].Our intimate relationship with digital tools has become existential, as the digital items humans create fundamentally change who we are.This poses serious questions on how we view humanity, human bodies and rhythmicity associated with them.
Rhythm Analysis.Costello [75] has applied rhythm analysis in HCI and stated: "to focus on rhythms within the lived relations between humans and technology is to focus on unfolding processes, dynamic temporality, and patterns of change and continuity."Rhythm analysis as a method is largely based on studies from Lefebvre and Régulier, who studied what rhythms can reveal about the temporal processes of social regulation and the ways in which bodies are trained or tamed to behave in, for example, everyday life.Costello [75] underscore their attention to repetition, difference, time, mood, atmosphere, and cyclic and linear interactions.The benefit of rhythm analysis is in making sensible often hidden structures, processes, influences, and interferences and in exploring process, emergence, and patterns of stability [75] all seen as valuable also in HCI.

LITERATURE REVIEW METHODOLOGY
Informed by the literature presented in the previous two sections, we analyzed CCI literature to identify the state of the art as well as paths for future work.We selected a narrative literature review method as we are dealing with a topic without established terminology [12].Narrative literature review is "a creative process through which a researcher identifies and examines prior research and develops [an] increasing understanding of a phenomenon under examination and in the process constructs the relevant body of knowledge.(. ..)A researcher uses judgment and discretion to classify, critically assess, and determine the importance of individual studies and their contributions to knowledge" [12], p.164).Through this review, we offer an overview, mapping, and critical assessment of previous research [12].We focused on the premier CCI outlets, including two conferences: (1) Interaction Design and Children (IDC) Conference, (2) the Conference on Human Factors in Computing Systems (CHI), and (3) the International Journal on Child-Computer Interaction (IJCCI).Employing advanced searches, we sought abstracts containing keywords: "child," "nature," and "rhythm".We started with searches for literature on nature and children from the past decade.After examining the results and the location of relevant studies and examining their keywords, we added the keywords from living world like "plant," "animal," "nature AND bio," and "nature AND eco."Thereafter, we searched for literature on rhythm and children using those as keywords.After examining the search results and informed by the theoretical framework, we added the keywords "body OR bodied" and "embodiment".
Two researchers conducted the searches, which produced well over 100 studies; they then made initial interpretations of the inclusion and exclusion of studies based on the title and abstract.This procedure resulted in a dataset of 127 studies for the second round of analysis, during which information on each study and how nature and rhythm had been addressed in the study was recorded.During this iterative process, a set of inclusion and exclusion criteria was developed.Studies were included if they addressed (1) children and (2) design and/or technology (3) nature or natural rhythm in the sense presented in sections two and three.After removing duplicates, studies not addressing children, and studies eventually deemed not nature or natural rhythm oriented, a total of 109 studies were included for the analysis conducted jointly by the two researchers.As for nature, clear categories of studies started to emerge in a data driven manner, aligning yet closely with the categorization of [39]: some topics had received notable interest, with larger groups of studies identified.Those concerned (a) studies advocating playing and learning IN nature and outdoors, (b) studies aimed at building children's relationship WITH nature, and c) studies that concentrated on encouraging children to take action FOR nature.As for the rhythm, some studies explicitly discussing natural rhythm were found, which addressed 1) body rhythms or 2) embodied interaction.These studies can be considered as taking steps towards seeing children as PART OF nature or natural rhythm.The analyzed studies are included in the Appendix, with the associated analysis codes.

CCI RESEARCH ON NATURE AND RHYTHM
This section provides an overview of CCI research that addresses nature and/or natural rhythm.In general, CCI research, similarly to HCI research, has proposed a number of digital solutions as well as utilized some design approaches addressing children's relationship to nature and natural rhythm.However, CCI research still lacks many aspects already studied under HCI regarding the topics.The state of the art in CCI research is discussed next, after which several interesting paths for future work are identified.

State of the art in CCI research
Studies addressing nature.Scholars are interested in CCI research on the topic of nature [8,28,58,89], [107], [111].CCI studies pointed out an increasing disconnect with nature [30], even a "biophobia" among children [28].The studies identified many benefits from children's engagement with nature, including health, well-being, and learning.Some studies provided digital support for children's outdoor activities and outdoor play, considering how the nature setting and the availability of natural materials contributes to play activities [9].Some studies focused on augmenting children's learning outdoors, connecting with subjects such as biology, ecosystem, bio-design or environmental studies [25,26,28,34,58].Some studies aimed at enhancing children's engagement with and education on plants and animals [ [6,9,18,44,58,63,69,96], [119], [124].Some studies concentrated on children's relationship with nature: encouraging children to spend more time outdoors and facilitating their nature play and nature interactions are seen to promote their connectedness with nature, which is viewed as valuable for health, well-being, and environmental stewardship and conservation [10,58], [111].
Overall, CCI research has provided various digital tools for engagement with nature (see also [3]): for instance, a game for increasing environmental awareness [89], an interactive solution for children's digital-physical play in natural outdoors settings [8], meta-manipulatives for exploring local environments [91], game around topics such as pollution and animal rights [64], an application to contribute to the natural resource consumption problem [68], and a mobile application to encourage children to spend more time outdoors and to promote their connectedness to nature [58,59].Children have also been engaged in co-design or participatory design in this context: they have envisioned new digital tools for supporting child-nature interactions and nature play as well as for environmental stewardship, sustainability and biodiversity preservation [27,28,30].Even the participatory role of animals has been discussed [22].
Kawas and colleagues [58], inspired by Giusti and colleagues [39], discussed a human-nature connection framework in relation to children, identifying three consecutive phases: children (1) being IN nature, (2) being WITH nature, and (3) being FOR nature [58].The existing CCI literature nicely maps with this framework: many studies advocate playing and learning IN nature and outdoors, while many also aim to build children's relationship WITH nature through different kinds of learning and play activities.In addition, some studies concentrate on encouraging children to take action FOR nature.However, we also see some aspects lacking in this categorization: the CCI literature could even more strongly emphasize that children are PART OF nature and its natural rhythm.This will be discussed next.
Studies addressing natural rhythm.Some CCI literature addressed rhythm, although many aspects discussed in this study are missing.Children have been provided with a breathing exercise game based on music rhythm, linking with the body rhythms [49] and digital tools for music education have been developed [82,93], [125], [130].A rhythm game for increasing cultural appreciation, in which children engage in traditional folk music and song [40] and digital tools for exploring musical rhythms [48] or the relations between mathematics and music [17] are reported.Rhythmic joint action between autistic individuals and their parents and siblings has also been digitally supported [21].Additionally, rhythm appears in CCI studies in the form of embodiment.The embodied interaction paradigm has inspired several above mentioned CCI studies on rhythm [21], [125], [130].Although rhythm is not actually discussed in all embodiment studies concerning children, these studies show that the body is a rhythmically moving, functioning, dynamic entity in interaction with itself and the environment.The concepts of embodied interaction , [112], [133] and embodied learning ( [133], relating conceptual learning to bodily experiences) and learning through bodily experiences [112] are used in studies concerning the body.Antle [4] noted that embodied interaction has influenced the CCI community for over a decade and for over 20 years has been studied with respect to how movement informs learning and cognition.CCI research shows that the body is involved in internal interactions, such as in the relationship between brain activity and the functions of the human body (e.g., [35]), and in external interactions ( [21,60]), as the body acts as a conduit through which interactions can happen [21] with open-ended interaction scenarios to collaboratively create narratives through bodily play and learning, both in design and in technological solutions [18,83], [113], [130], in body learning mathematics [20], [128], [112].Nygren et al. [90] provided an overview of literature on body interaction, compiling 9 articles on embodiment and 13 articles on whole body interactions and digital technologies and contributed to the CCI community by offering methodological insights.

Initial design framework for CCI to address nature and natural rhythm
We emphasize the importance of children's connection with nature and its rhythm in today's digital society.We categorized CCI research on the topic the following way (modified, based on [58], Giusti and colleagues [39]: 1) CCI research on being IN/WITH nature, 2) CCI research on being FOR nature, and 3) CCI research on being PART OF nature.The first two categories have already been examined, to an extent.CCI studies have investigated outdoor play, learning outdoors/in/about nature, and child-nature interactions and play.Additionally, some CCI studies support and design for environmental stewardship and conservation.Hence, nature clearly is perceived as important in many ways.However, we think also these two categories can be enriched.For research addressing children's interaction IN/WITH nature, we recommend, for example, in-depth studies on how the digital world and nature form complex hybrid constellations in which children interact with nature, with different kinds of living creatures (and nonhuman objects, including digital tools), and with varying kinds of materials.We should be designing for such constellations and appreciating and exploring in-depth the experiences and consequences within such constellations.Moreover, as for studies on children FOR nature, the current critical, empowering approaches that are starting to feature strongly in CCI research (for reviews see [47,80], ) can be utilized more: CCI research has for long invited children as co-designers to shape our digital futures, while now the interest is on empowering children to start acting as protagonists who design and develop technology, critically reflect on it, and utilize such technology to make the world a better place and to fight against marginalization, domination, oppression, and exclusion e.g.[31,51,52].Such approaches should be of use when encouraging children to act FOR nature.
The most neglected research category concerns children being PART OF nature and its natural rhythm.CCI research has not engaged children in reflection on their intimate relationship with nature and its natural rhythm.This approach should be taken with children to acknowledge that humans are part of nature and are rhythmic beings, shaped by, including, and entangled with various kinds of biological and body rhythms.So far in CCI research, rhythm is mostly addressed in the context of music, although in one study the importance of support for children's breathing is acknowledged.Moreover, the embodied interaction paradigm has Somaesthetic design: to design novel digital tools and interfaces that support children's body consciousness, bodily inquiries, articulation of bodily experiences, e.g., with wearables, sensors, virtual or augmented reality.Inbodied interaction: to design novel digital tools and interfaces supporting and making visible the body's internal systems and processes, e.g., with wearables, sensors, data visualizations.Circumbodied interaction: to design novel digital tools and interfaces supporting and making visible processes both external to the body and inbodied; reflecting on the boundary of inbodied and embodied, e.g., with wearables, sensors, data visualizations.already informed design in CCI; yet, the other approaches addressing rhythm we identified are missing.This research category of children being PART OF nature overall underscores the study of and support for the rhythm of nature in children's lifeworld, with the goal of maintaining natural connections in the digital world.For this category of CCI research, we identified a number of interesting paths for future work (see Table 1).
Next, we discuss these paths for future work, concretizing them with an CCI research examples, which should clarify how CCI and HCI researchers may integrate these ideas into the design process and outcomes.
Exploring the potential of rhythm analysis with children.We see a lot of potential in exploring rhythm analysis in collaboration with children for the purpose of strengthening their being PART OF nature and its natural rhythm.We envision a CCI project in which rhythm analysis is used as s starting point for the design process.Both child and adult researchers and designers as well as potentially also teachers are to be invited to act as time-focused, body-thinking rhythmanalysts, "who train their senses and make themselves sensitive to the finest movements and changes around them" [66,77].They engage in "rhythm analysis," in which the body constitutes the starting point, while the rhythmanalyst also considers movements among people and in nature [66,77].Under exploration are temporal processes of social regulation and the ways in which bodies are trained or tamed to behave in everyday life.The participants are sensitizing to their body rhythms, e.g., to their breathing and heartbeat, and dynamics shaping them, but also to biological rhythms within their everyday life: to their daily, weekly, monthly and yearly rhythms and on dynamics and factors shaping those.We see important to consider how digitalization is shaping those rhythms as well as whether and how the participants have become alienated from the nature and its natural rhythm.Overall, the rhythmanalysts should have a sensitized bodily presence and they should be noting, understanding and intervening in the rhythms of the everyday: the analyst should be attempting to apprehend the rhythmical qualities of everyday life -in our example project this acts as a basis for the design activities to follow.It is essential that the CCI researchers and designers are able to guide the children (and their teachers) to adopt the position of a rhythmanalyst, which guides individuals to appreciate the inherent and wide-ranging rhythmicity of our everyday life in a deep sense, giving an elaborate basis for designing for and in concert with the natural rhythm.
Exploring the potential of somaesthetic design with children.For our example CCI study, we also see a lot of potential in engaging children in design approaches acknowledging the body and its natural rhythm as a starting point, medium and context of design.Somesthetic design provides a novel approach for CCI that should be explored in collaboration with children.We envision in our example project children and adults engaging in somaesthetic design, which starts by sensitizing how we are in the world acting in the social and physical environment along with the physical body, not separate from it [46], and continues by collaboratively designing with, through, and for the unified body/mind [7,75].Such design process invites both children and adults to bodily inquiries, articulation of bodily experiences, sensitive body consciousness, acknowledging rhythm in moving and experiencing the lived body, emphasizing the importance of first-person experiences [46,106].
Participants with existing relevant sensitivities, like dancers, yoga practitioners, and athletes, could be beneficial participants in the design process [75].We also see a lot of potential in theater based approaches [103] and live action role playing approaches [74] for embodied design and for increasing embodied awareness.We see also nature as an integral element: the participants are not only considering and designing for the unified body/mind, but also with and for the connection with nature: bodily inquiries, bodily experiences, sensitive body consciousness IN, WITH and as being PART OF nature are emphasized.Overall, somaesthetic design enables to take a step further from rhythm analysis: it entails engaging in design, not only analyzing the rhythmicity of the body and the everyday; hence, child and adult designers, based on their rhythm analysis insights, can engage in design for the unified body/mind, for rhythmicity, for better support for natural rhythm Exploring the potential of inbodied and circumbodied design with children.As for the rhythm sensitive inbodied and circumbodied design, the processes and systems internal to the body and their interactions with the external world and its rhythms provide fascinating paths for future work.In our example CCI study, this entails engaging children in monitoring, reflecting on and designing for the internal body processes, for example for the five fundamental-to-life processes: move, eat, engage, cogitate, and sleep [105], entailing monitoring, reflecting on and designing for their rhythmicity.The targets of design can be decided based on the rhythm analysis results; yet, many valuable learning goals, e.g., from biology, could also be integrated to guide this work.We do not see it immediately recommendable to start designing and implementing solutions for children's imbodied processes, but as the anatomical and physiological model of the adult becomes clearer in HCI research, the work can be considered with children.The work would be valuable as children's health and well-being can be improved when HCI research is able to gain functional access to the key internal and external processes that affect human health, well-being, and performance and their interactions.However, we emphasize the need for a multidisciplinary team, including child development and medical sciences experts.
Addressing biological rhythms with children.We have already envisioned how children in our example study are exploring biological rhythms as rhythmanalysts.We also see a lot of potential in designing for those utilizing somaesthetic, inbodied and circumbodied design approaches.Different biorhythms are under consideration in current HCI research, while CCI research yet lacks this focus, even if some studies have utilized sensor data to understand children's sleep (e.g., [54,94], [127]).We think CCI research should focus more on the circadian rhythm of children, as support for children's daily rhythms is valuable for so many aspects of children's health and well-being, not only related to their sleep.We envision children (and potentially also their parents and teachers) acting as rhythmanalysts on their circadian rhythm, considering potential problems within and design support for it.Important is also to consider on a broader scale that the rhythm of everyday has shifted as a result of the industrialization and digitalization of society.It would be essential to study children's circadian rhythm from this perspective; how well it aligns with the natural rhythm.The circadian rhythm is also pivotal in children's education: "The most prevalent research on rhythms in education today deals with the influence of the 24-hour circadian rhythms on pupils' attention during the school day" [67].CCI research should analyze and provide better support for the circadian rhythm of children in education, in collaboration with teachers, inquiring: How children experience the rhythm?What is beneficial for their well-being?How can we better support their circadian rhythm in education and thus their health, wellbeing and learning?We should also consider this rhythm from the viewpoint of design activities with children, in the context of school as well as elsewhere, asking: How do our design activities fit with the circadian rhythm of children, both in beneficial and in harmful ways?What kind of daily rhythm do our design activities introduce or interfere with?The same questions can be asked in relation to children's infradian, circannual, and diurnal rhythms: how can we make these rhythms visible for children and design support for these rhythms, such as for weekly, monthly, and yearly rhythms, which include yearly celebrations, school schedules and holidays, and seasonal rhythms?Circannual seasonal rhythms and festival rhythm around the world follow the rotation of Earth around the sun.CCI research can aim at making these rhythms visible to children and design support for them.An interesting future direction is the monthly cycle of the moon and its influence that requires more attention in research [97].
Addressing body rhythms with children.We have already envisioned how children in our example study are exploring their body rhythms as rhythmanalysts and designing for those utilizing somaesthetic, inbodied and circumbodied design approaches.We acknowledge that the body rhythms related to breathing and heartbeat have already received attention in the HCI literature and breathing support has even been provided in CCI research.Children are not only considered in the respiratory area in healthcare [45]; they also have been provided with visual biofeedback on their breathing in breathing exercises, when blowing bubbles to music rhythm with visual guidance [49], or with haptic feedback through wearable e-textile shirts [88].These studies not only encourage the continuation of breath-supporting design but also develop children's awareness of the body and their own breathing.Overall, we feel this design space should be explored further in CCI.Along these lines, we imagine that both child and adult designers are guided to listen more to their body, breathing, heartbeat, and whole organisms.They are also encouraged to design support for this listening as well as engage in such listening within the design process, to understand how their designer bodies are engaged in and reacting during design -exploring what they are telling us.Existing CCI research has already collected multimodal sensor data through, e.g., eye-tracking or wristbands with sensors for heart rate variability, blood pressure, temperature, and electrodermal activity levels (e.g., [65], [127], [129]).We think that use of this equipment and data could be considered also in our studies and reflections on our body rhythm.Additionally, we should be observing how being IN and WITH nature affects our body rhythms and potentially derive design implications from that.Research (e.g., [33,108]) already shows that awareness of the breathing rhythm in nature should be further developed along with knowledge on nature within design research.We also wish to take a step further and consider breathing as a key common denominator between natural organisms.As mentioned, we consider everything living as rhythmic and, thus, in motion.At the same time, we can ask whether the rhythm of nature is actually breathing, moving in and out, inhaling and exhaling?And could this be a model for the design of movement within and into the digital world?Can the normalized two-part breathing signal be the model of movement (from 0 = no air in the chest, 1 = chest fully inflated) of a natural, healthy digital world?And could it be the model for the fluent movement of children from one world to another?
Addressing entanglements.Finally, when designing for a digital world that is breathing, discussions on entanglement HCI (e.g.[36]) are relevant.This perspective brings a more philosophical orientation to CCI: addressing the entangled relations between humans and nonhumans, all entangled within the digital world in complex ways.Rhythmic thinking can be supported by acknowledging that humans and technology can no longer be investigated as if they were separate stable entities but instead they must be viewed as complex breathing constellations in constant motion and transformation.Currently, CCI design is stable concerning children's tools (black box outside of the body).CCI research should better acknowledge that natural rhythmic movement is and should be present when designers are composing a human-world relations [75].

CONCLUSION
This study explored how CCI research has addressed nature and natural rhythm and how they can be better acknowledged in CCI research.To summarize the results: We showed that nature and natural rhythm picture in various ways in CCI research: children being IN/WITH nature and being FOR nature have already been addressed, to an extent.More importantly, we showed that CCI research that addresses children being PART OF nature and natural rhythm is limited.We indicated many ways by which HCI research can inform us in addressing this important topic.For example, we underscored that biological rhythms should be better acknowledged and supported in CCI research, concerning both the design process and outcomes, including the circadian, infradian, ultradian, circannual, and diurnal rhythms, both in the physical and in the digital world.We also brought to the fore that various kinds of body rhythms should be appreciated in the design process and addressed in future designs.We also discussed the relevance of somaesthetic design and inbodied and circumbodied interaction for CCI research and maintained that scholarly focus should extend beyond the design of single digital tools in isolation.Moreover, we should acknowledge rhythms much more broadly and how the digital world we are creating is or is not rhythmic or breathing, to enable the rhythm of nature in the digital world.
As for the contribution to and implications for CCI and HCI, we offer a novel design framework for research on nature and natural rhythm with valuable research directions for the future.Future research can, inspired by the framework, start developing novel rhythm sensitive design processes as well as novel digital tools and interfaces to support children being PART OF nature and its natural rhythm, including, e.g., educational, health and wellbeing solutions and robot, sensor, augmented reality and data visualization based solutions.Our study contributes also by underscoring the significance of natural rhythm in the digital world.This way of thinking challenges many taken for granted assumptions and opens something new in the field of design, also for and with children.Several studies have shown that rhythm is a remarkable concept as such, but especially in those areas of design, where the central point is on the rhythmical human being with the outer surrounding and inner organs.Approaches of embodied, somesthetic, inbodied, and circumbodied interaction have already pointed out fascinating directions for future HCI studies and have underlined the meaning of the whole human body interacting with the environment.We underscore the importance of rhythmicity in children's lives in CCI research, including in school context that is a central context for CCI.School entails different lengths of rhythmic cycles that CCI research should consider regarding both the design processes and outcomes.Time in education appears as rhythms.Language, learning, and communication are embedded in rhythms [26,53,107], and there is a musicality to all human interaction [71,99].The days and weeks of a school year are organized into periods, lessons, and homework activities.Within this fine-grained and often fragmented rhythmic structure, the deepest processes of learning and development are expected to take place, and children spend substantial part of their lives.Still, the phenomenon of rhythmicity in educational settings has scarcely been investigated or developed.CCI research and design related to education should consider and try to support such rhythmicity.In relation to nature, concepts such as alienation, constipation, or even phobia in research results tell us that our rhythm is not natural and breathable.We argue part of the problem is the lack of natural rhythm.The digital world has an influence on this, but paradoxically, at the same time, it brings out solutions to this problem.Our hope is that CCI takes natural rhythm into consideration much more seriously, working together with other disciplines, and creates design directions that support a natural rhythm-the way of breathing and living.
As for limitations, we provided only a limited literature review on this topic, even if we used a multitude of keywords to search for the literature and derived inspiration from numerous disciplines.In the future, additional reviews, but more importantly, empirical and designerly interventions are needed.As for the literature reviews, some more studies might be findable in CCI and HCI as well as in disciplines specializing in nature and natural rhythm -both for developing the theoretical framework as well as to be included in the literature review.As for the empirical and designerly interventions, we hope, in the middle of arrhythmia and alienation, and even constipation, that the CCI research community continues to advocate sustainable development and remains sensitive toward the surrounding nature as well as natural rhythm in collaboration with the developing child, seen as a part of nature.We call for CCI researchers and designers to try to ensure that the ongoing rhythm of nature remains transformational and breathable in entanglements of humans and the digital world.

Figure 1 :Figure 2 :
Figure 1: The most striking rhythms of cosmos

Figure 3 :
Figure 3: Rhytms of breathing and other body organs

Table 1 :
Paths for future work for CCI to address children being part of nature and its natural rhythm.
A1 = nature and related concepts; A2 = rhythm and related concepts