NOTICE: This is the author’s version of the following article.
Nakamura M (2009) Interaction studies in Japanese primatology: Their scope, uniqueness, and the future. Primates 50:142–152.
DOI: 10.1007/s10329-009-0133-6.
© Japan Monkey Centre and Springer-Verlag. The original publication is available on SpringerLink at http://link.springer.deInteraction studies in Japanese primatology: Their scope, uniqueness,and the futureMichio Nakamura
Wildlife Research Center, Kyoto University

Abstract
This paper aims to review social interaction studies in Japanese primatology, in order to introduce their utility into thecurrent framework of primatology and their potential for understanding primate sociality. In the first part, I introduce
some of the achievements in the field of Japanese primatology. It is a well-known fact that Japanese primatology, in
its initial phases, strongly focused on society and sociality in nonhuman primates with respect to human society andsociality. Although Jun’ichiro Itani’s theory on the evolution of social structure significantly influenced some of theJapanese primatologists, it had a comparatively minor impact on the West. As Itani himself admitted, he only treatedthe so-called “hardware” of society and did not deal with its “software” comprehensively, although he understood its
importance and even provided some insightful ideas. In the latter part of the paper, I introduce some of the studies
that directly dealt with the social interactions of primates and that were written mostly in Japanese. As compared toworks in standard primatology, many of these papers were descriptive. This is because interaction cannot be decomposed into individual behaviors; thus, we have to focus on interaction itself. Finally, I argue that we need to explore
the methodology for describing the lively and dynamic aspects of primate sociality.

Key Words: social interaction, Japanese primatology, dynamism of society, qualitative description

Why Primates Interest Us
Imagine a child visiting a zoo with his parents. He
looks into the monkey enclosure and is attracted towhat he sees there. Monkeys and apes always interest anovice. It appears that the monkeys’ social interactions
instantly attract children toward them. The child neither
knows about the social structure of the monkey species
nor does he know how a particular behavior can beadaptive or beneficial in the sociobiological sense.
Therefore, it is not such knowledge that makes themonkeys’ interactions appear interesting to him. Although they may notice that monkeys are somewhat
similar to humans, children do not know and are notconcerned about whether monkeys are taxonomically or
genetically close to humans. Of course, for professional
researchers, the structured societies of primates or behaviors that can be suitably and parsimoniously explained using individual reproductive strategies are theattractive features for academics. However, this does
not imply that the sociality of primates is not understandable or interesting without such current academic
frameworks. Researchers do (or did) have the samenaïve interest as that of the child mentioned above, andthis initial interest could be a possible reason their de-ciding to become primatologists. However, as scientists,they can no longer pursue the same naïve interest;
rather, they have to place themselves in the current
academic frameworks.
Nevertheless, I believe that such a naïve interest
should not be abandoned. It is important for researchers
to visit the field in order to gain first-hand impressions.
However, may they report the vivid impressions they
actually observe in nature? Do primatologists actuallyfocus on interesting aspects of primates, such as theirlively social interactions, which even a child immediately notices? In other words, can primatologists write“ethnographies” about target species or societies in thesame manner that anthropologists write about theirtargets? The answer can be both yes and no. It is “yes”
because early primatologists wrote “ethnographies” inthe form of books for general public (e.g., Itani 1954;
Goodall 1971; Nishida 1973). In such books, the lively
interactions of monkeys and apes were vividly described and still retain their brilliance. Although it iseasy to say that these earlier descriptions were notpurely academic or scientific, it is true that such classic
primate “ethnographies” help us understand the realityof the social world of monkeys and apes even beyond
species (Sugawara 2002). The answer is “no” becausetoday, this method of describing primate behaviors is
becoming devalued. At the very least, the methodologythat observes and describes the actual behaviors ofmonkeys and apes now seems to be regarded as
old-fashioned or even nonscientific. Now, researchers
have to define and to categorize behavioral patterns inorder to make them suitable for statistical testing andsometimes they provide only statistical values in theirscientific papers. I sometimes face difficulties in understanding a particular categorized behavior, because
authors only summarize the subtle variations to a single
behavioral category and seldom provide a rational explanation for such categorization. In such cases, it canbe said that the reality of the particular behavior is lost.
Although lively social interactions are not limited
to primates, it is often easier to observe and record suchinteractions in primates than in other animals because
most primates live in gregarious and stable socialgroups usually terrestrial (as opposed to aquatic) anddiurnal. This paper provides an overview of the historyof Japanese primatology from the standpoint that the
fascinating aspect of primate sociality lies in their vividsocial interactions. I will mainly review the publishedliterature on primate societies and social interactions
written in Japanese. There are three reasons for this:First, this special issue of Primates is meant to commemorate the 60th anniversary of Japanese primatology; thus, it is appropriate to focus on this field. Second,
as a native Japanese speaker, I am aware that papers
written only in Japanese or papers that can only be
expressed in Japanese contain unique ideas and important observations. I will not be able to introduce all theideas that even their original authors could not express
in English; however, it will still be useful to introduce
these ideas at least to some extent. Third, studies basedon such detailed descriptions of social interactions aremostly written in Japanese (or in English by Japanese
primatologists). This may be because, as is often
pointed out (e.g., Asquith 2000; Takasaki 2000), Japanese (particularly traditional Japanese) primatology andWestern primatology adopted rather different approaches (but see McGrew (2007) who emphasized thelinks rather than differences between Japanese andWestern primatology). Today, many Japanese researchers adopt the Western approach, perhaps because theJapanese academic world now requires them to write
papers in international journals. Ideally, the quality of astudy should not be judged by the language in which itis written but instead purely by its content. However, inJapan, it is often assumed that a paper published in an
English journal is superior to that published in a Japanese one (of course, the citation index is usually higher
in the former owing to its wider readership). Thus,
young Japanese researchers avoid such Japanese approaches and intentionally or unintentionally adopt theWestern approach, which is more readily accepted ininternational journals.
Theoretical background of Japanese primatology,
especially the focus on sociology of primates, is often
attributed to Kinji Imanishi (e.g., 1941, 1951, 1966)
and his ideas have been relatively well introduced in

English language (e.g., de Waal 2001, 2003; Asquith
2002; Nakamura and Nishida 2006; Matsuzawa andMcGrew 2008). Therefore, in order to avoid repetition,
I mention little about Imanishi’s ideas but instead startfrom discourse made by Jun’ichiro Itani whose ideas
have been relatively less introduced to English readership. Some, or maybe majority, of Japanese primatologists may not be completely happy with my understanding of the history on Japanese primatology and its
interpretation. However, in the context of social interaction studies, I believe my standpoint will provide
some useful insights to the future research perspectives.

Achievements in the Field of Early Japanese Primatology
When research began to be undertaken in the fieldof Japanese primatology, understanding societies orsociality was the most important objective (Imanishi
1957; Itani 1985a). It is often said that traditional Japanese primatology was concerned with sociology rather
than biology (e.g., Muroyama 1998). Although someJapanese researchers have given more weight to biology (e.g., Sugiyama 2000), many primatologists, particularly those from the Kyoto School (sensu Takasaki
2000), attempted to understand the societies of living
things without limiting their methodology to purely
biological concerns. The following statement by Imanishi appropriately indicates the situation: “What I wantto conduct is research on the historicity of animal societies that can only be understood by accumulating
thorough records. Such records can only be obtained bydescribing the dynamism of the societies in place of theanimals themselves who do not have language or lettersto do so” (Imanishi 1960, my translation).
One of the well-known achievements in the field ofJapanese primatology that is recognized worldwide is
the prediction and discovery of primate cultures (Imanishi 1952; Kawamura 1959; Kawai 1965; Itani andNishimura 1973; Nishida 1987; also see Nakamura andNishida 2006 for a review). Such early studies on primate culture are highly praised by Western primatologists (de Waal 2001; McGrew 2004), and the famous
paper on sweet potato washing (Kawai 1965) is often
cited by Western researchers even today (e.g., van
Schaik et al. 1999; Rendell and Whitehead 2001;
Boesch 2003).
Apart from such well-recognized achievements,
studies on the evolution of primate social structures by
Itani (1977, 1980a, 1981, 1987), who emphasized theimportance of phylogeny and some type of fundamental“rules” or “institutions” for societies, had a certain
influence to some Japanese primatologists (e.g.,
Yamagiwa 1994; Furuichi 1999; Kuroda 1999); however, they did not seem to get much attention in theWest although some part of the idea was also publishedin English (Itani 1977, 1985b). Itani’s discussions on
primate social structure both influenced and were influenced by the elucidation of the social structures ofgreat apes by some Japanese researchers (Nishida 1968;Kuroda 1979; Sugiyama and Koman 1979; Kano
1982).
Itani’s methodology, which discusses the evolutionary pathway by understanding society as a structureusing basic data such as group composition, number ofgroup members, and the transferring sex, became atrend at least in Japan. Many Japanese primatologists
once devoted themselves to the search for primate social structures and their evolution. Although this trend
declined with the rise of socioecology, some researchers still try to develop Itani’s theory on the evolution ofsocial structure within the framework of socioecology(e.g., Yamagiwa 1999; Furuichi 2006).
Itani’s theory on social structure superficially resembles current socioecology in some aspects such thatboth grasp a society as a structure in relation to thespatiotemporal dispersal pattern of different sexes, butdiffers in others. In socioecology, social organization isregarded as the outcome of the strategies employed byindividuals to meet their basic requirements and can be
regarded as an instrument used by individuals that
achieves the social structure (Wrangham 1980; van
Schaik and van Hooff 1983; Sterck et al. 1997). On theother hand, Itani’s social structure is more group-based
and phylogenetic continuity and group “heredity” (i.e.,transgenerational conservation of characteristics of asociety) are considered to be important.
Following the rise of socioecology, there were critiques that phylogeny has to be considered in addition
to current ecological factors (Rendall and Di Fiore
1995; Foley 1996). Although Itani had emphasized theimportance of phylogeny with respect to social structures more than 15 years before, Western scholars did
not grasp this importance, or if they did, they disregarded it.

“Software” of Society and Anti-structure
As mentioned above, although social structure theory was once dominant in sociological studies of primates in Japan, a slightly different movement began in
the period from the late 1970s to the 1980s. This period
corresponds to that when Itani basically had completed
his work on primate social structure and shifted his
main interest to studies of the ecological anthropology
of farmers, hunter-gatherers, and pastoralists who werestill considerably dependent on nature (e.g., Itani
1980b). Some young researchers and students studying
nonhuman primates began to target social interaction
itself rather than social structure as the main theme of
their studies. Itani (1988) once dubbed this small groupof people an “Interaction School”, himself not being
directly involved in it.
Moreover, Itani himself admitted that although hehad been studying the so-called “hardware” of society,further research on the “software” of society was required thereafter (Itani 1987). Here by “hardware” hemeant structure of a society, and by “software” behaviors and social interactions that make co-existence ofindividuals possible and that make the social structure.

Although his main discussions on primate societies
concerned hardware, he sometimes also discussed thesoftware of society; one such discussion was “Discourse on the Origin of Equality” (Itani 1986), which
dealt with the equality and inequality in the society ofprimates, including humans. This work was definitely
inspired by “Discourse on the Origin of Inequality” by
Rousseau (1755). As is widely known, Rousseau argued that all primitive natural men were equal andanonymous; social inequality then followed as society
evolved. Using the knowledge obtained from primate
studies at that time, Itani argued that Rousseau’s concept of initial equality should be traced back to elemental societies of nonhumans, such as those of solitary prosimians, and termed such societies those of“equipotency.” This type of society is based on individuals who avoid each other and was the prior stage tothe societies that ensured equality and inequality
through social interactions. As the next step, he considered a pair type of social unit that can be found in various clades of primates and termed it a society of “pristine equality.” Societies with a larger group size andwith female philopatry, such as those of Japanese macaques, were regarded as societies of “pristine inequality.” This type of society, Itani argued, was based on theprinciple of matrilineal kinship and strict dominant-subordinate interactions. In such pristine inequality, when individuals act as if such inequality does notexist, “conditional equality” emerges. Good examples
of such conditional equality are observed in social playor food sharing in great apes (Itani 1986).
Another important but lesser known discourse on
the software of society by Itani was “Behaviors that
Make Social Structure” (Itani 1981). In this paper, he
first admitted that any behavior can be described only
by using language, and by analyzing the verbs used in
the primatological literature, he classified eight strata of
behaviors (brief English introduction by Nakamura, inpress). Itani emphasized that affirmative/negative andactive/passive forms of a verb “forgive”, i.e., a quadrantof “forgive/not forgive/be forgiven/be not forgiven”
were critically important in the formation of social
structure (it should be noted that the equivalent Japanese verb for “forgive” also have a nuance of “tolerate”).
Another important concept that is relevant but cannot really be categorized as software is “anti-structure”(Itani 1991). This concept can be used with reference tosolitary males among Japanese monkeys (Nishida1966) or all-male groups of gorillas (Yamagiwa 1987),
which is in contrast to the gregarious andwell-structured (as observed in the dominance hierarchy) nature of bisexual groups. After focusing on the
structure of primate societies, Itani later stated that anindividual primate can move from structure toanti-structure and then back to structure; therefore,
structure and anti-structure should be regarded as awhole set in the context of the formation of a society of
one species. This idea is important in that Itani understood that his discourse on social structure was notcompleted and required another dimension.

As discussed earlier, Itani, who had one of the significant influences on the theoretical aspect of Japanese
primatology after Kinji Imanishi, pointed out the importance of software, although he mostly devoted his
works to tracing the evolution of the hardware of society or the social structure. Barring the fine-grained
descriptions of Japanese monkeys in the early period(e.g., Itani 1954), he conducted no study of social interactions of primates by himself. However, he shiftedto studies of ecological anthropology and later to a
macroscopic study on African vegetation in relation tohuman evolution (Itani and Terashima 2001).

What is Interaction?
In current studies in primatology, the terms “social
interaction,” “social relationships,” and “social structure” mostly are used according to the formulation byHinde (1976), in which multiple interactions form a
relationship and multiple relationships create a structure.
Therefore, interaction between two individuals is thebasic element of a social structure. Hinde also emphasized the necessity of generalization with regard to thesame characteristics and search for principles in orderto provide causal or functional explanations. He statedthat “interactions need be considered only briefly,” andhe formulated social interactions simply as “A does X
to B” or “A does X to B and B responds with Y.”
In the usual usage of the word, interaction is “akind of action that occurs as two or more objects havean effect upon one another” (Wikipedia 2008a), where
the objects do not have to be living organisms. In sociology, the usage of “social interaction” changes slightly,
for instance, it can refer to “a dynamic, changing sequence of social actions between individuals who modify their actions and reactions according to the actions
by their interaction partner” (Wikipedia 2008b). From
this definition, it is understood that social interaction
comprises two or more actions (≈ behaviors); however,it cannot be decomposed into actions. More precisely,
the very nature of an interaction cannot be understood
if we decompose it into actions. Therefore, in order tostudy interactions, we have to target interaction as awhole set. An individual’s mental state (e.g., motivation
or intention), physiological state (e.g., hormones), or
genetic background for a particular action or behavior
is definitely related to the occurrence of an interaction.
However, the nature of interaction cannot be understood by classifying it into such different lower levels.
Although Hinde (1976) also pointed this out by
stating that “it has properties that are not present in the
behavior of either participant alone,” his above formulation appears to merely cover social behavior rather
than social interaction because “does X” can be attributed to the responsibility of individual A, while B can
only be a passive recipient. Additionally, the first formulation only includes a one-way action from A to B
and does not include B’s reaction. Even if B’s reaction
Y is included, it only appears to be an interchange of
behaviors. Therefore, this formulation does not seem tobe good enough.
However, it is not easy to formulate such interaction in a simple manner. The interaction between A andB may be described as follows:“...A does X to B, B does Y to A in relevance to X, A
does Z to B in relevance to Y...”The important point here is that the sum of X, Y,
and Z can never represent the complete interaction.
Although we have to extract some fragment of a dynamically changing interaction in order to record or
describe it, that part cannot be independent from thebackground. Moreover, it is important to note that X, Y,
and Z do not have to be a causal chain nor do they haveto linearly proceed in this order. Even when A does X,
B does not always have to do Y. The occurrence of X
may affect that of Y only in such a way that X narrows
the relevant actions following it, and there is always thepossibility that an action other than Y will be performedin place of Y.
The indecomposability of a social interaction into
actions may be related to the holistic idea of Japanese
primatology in its earlier phase (e.g., Kuroda 1986;
Takasaki 1999). Although the level is different, a society itself has a holistic characteristic that cannot be
understood by decomposing it to lower levels. This is incontrast with Hinde’s (1976) idea that the social structure can be decomposed to lower elements. Because thestandard of Western natural science basically relates todecomposing the world to some elements in order tounderstand it, such a holistic view may not be acceptable in the mainstream of primatology, which focuseson biology (biological anthropology, behavioral ecology, etc.), a subdivision of natural science. There seems
to be a general tendency that Westerners see a “tree”
while Asians see a “forest” (Nisbett 2003). This difference merely corresponds to two different aspects of one
phenomenon and neither is superior to the other. However, in Japanese primatology, following the introduction of sociobiology, several researchers began to question this holistic view of early Japanese primatology(e.g., Sawaguchi and Kudo 1987). Many of these researchers now attempt to only see a “tree,” as if theWestern way of looking at nature is the only correctway.
It is now widely recognized that the phenomenona
occurring in complex systems cannot simply be decomposed to lower levels (e.g., Kauffman 1995). An
alternative approach to reductionism is needed for suchcomplex systems, although it is sometimes difficult todevelop such an approach. Anyone who studies primates probably would agree that primate society is acomplex system. Such views that regard the holistic
aspects of sociality are slowly gaining acceptance as aresult of the recent increase in interest in primate cultures. Although it is obvious that an individual plays arole in the formation of culture, this does not imply thata culture can be decomposed to individual behaviors.
The actions of an individual cannot be termed as culture; rather, the term can be applied to the collective

actions of individuals (e.g., see McGrew 2004).

Observability
Although an interaction has holistic and noncausal
characteristics, it is still observable. This is in contrast
to the fact that a social relationship or a social structure
can never be observed directly. A relationship or astructure is a conceptual scheme that observers abstract
and construct after the accumulation of behavioral data
or interactions over time. Therefore, observers inevitably dissect the ever-changing social world within atime-frame in order to determine the status of relationships and structures.
A dominant-subordinate relationship can, for example, be observed in the case of individual A continuously showing subordination to individual B (as in
the pant grunting of chimpanzees: Bygott 1979). Usually, we do not use the term dominant-subordinate relationship if there is only one occasion of subordinate
behavior by A toward B, because it is possible that onother occasions, B might show subordination to A orotherwise, dominance among A and B is ambiguous (itmay depend on situations). Therefore, we need a defined time-frame in order to abstract such a relationship; however, the decision regarding the time span
usually depends on the observer. We shall consider thefollowing example:
Period 1: A shows subordination to B.
Period 2: B shows subordination to A.
Period 3: A shows subordination to B.
If each period is, for instance, 10 minutes long, we
will tend to think that there is no stable relationshipbetween the two (the dominant-subordinate relationshipis ambiguous). However, if each period is several years
long, we will then observe the stable relationship withineach period and say that reversals of the dominant-subordinate relationship have occurred. This simple example shows that we need some time-frame inorder to abstract relationships; however, the basis forthis time frame is arbitrarily fixed.
The same observation can be made with regard towhether the relationship has changed or no relationshiphas been established at all. In this sense, a relationshipis not a phenomenon that we can directly observe but aconceptual construction by the observer. There could bea counter-argument that there is no such problem if thedefinition of the time period is set prior to observation.
It is true that with such definition, we can determine
when to dissect our data; however, this does not help
solve this problem because such definition for a relationship can only be arbitrarily fixed by the researcher.
The above discussion is also true for social structure. Structure is not an observable phenomenon; rather,
it is only identified by an observer on the basis ofchanging membership and interactions among individuals within a particular time-span.
Interaction also needs a time-span in order to be

identified and the method of setting this time-frame
again depends on the observer. However, interaction isdifferent from the above two concepts in that it can beobserved continuously by an observer when it is occurring; further, it cannot be understood unless such observation is conducted. Therefore, the only phenomenon observable to the observer in reality is each interaction, and it is the observer who measures such interactions by assuming that different interactions occur atdifferent times and that they are of the “same” type.
It seems to me that in current primatology, terms
such as social relationships or structure are easily
adopted without thorough consideration of what theearlier researchers abstracted from their observations. It
may not be wise to consider the implications of theterms or the authors’ intent of the earlier definitions.
However, I believe that we should examine the realcontents of relationships or structures from the viewpoint of the concrete level of interactions in order togain a better understanding of primate sociality.

Dynamism of the Social World
The social world is always dynamic. This dynamism attracts both researchers and children at the zoo
toward primate society. However, at the same time, thisdynamism makes it difficult for the observer to describesocial phenomena. Researchers have to describe interactions by using language (cf. Itani 1981); however,when we do so, the descriptions become static. Thismay be because although language itself is a dynamic
system, written language used in such descriptions isusually static.
In the ethological sense, a behavior is determinedby classifying the participants in an interaction as anactive performer and a passive recipient, and the behavior is treated as if it belongs to the performer. We
can use check-sheets to record particular social behaviors with one-zero sampling only because we discard
the dynamic aspects of actual interactions and theirrelevance to the participants in each context. When wetry to grasp the interaction without discarding its dynamism in reality, it sometimes results in long descriptions of events that may be regarded as being too
wordy.
For example, Mori (1994) conducted a “story
analysis” on the social change process of bonobos at
Wamba. Here, by a story he meant a description and its
interpretation of consecutively occurring social events.
When one pools multiple social interactions for qualitative analysis, e.g., to calculate relative frequency,
he/she assumes that each interaction is independent
with each other. Instead, story analysis assumes thateach events are not independent but in causal relationships. By conducting this analysis, Mori attempted to
substantiate the anthropomorphic expressions often
seen in Japanese literature.
Itoh (2003) described the interactions constantly
seen in the fission-fusion of chimpanzees in the Mahale
Mountains. Although fission-fusion is regarded asunique characteristics of chimpanzee societies, it isoften considered only in relation to party size andcomposition (another construction that has been analyzed by researchers), which is not really fission-fusion
but only an outcome of it. Itoh’s description is the firstattempt to describe the ongoing mechanism of the dynamic fission-fusion phenomenon in chimpanzees. Her
description indicates that although salient behaviors
such as greeting or grooming do not always have tooccur, slight movements involving individuals whomeet and part always take place. She argued that what
is observed as a contour of a group or a party is madethrough everlasting movements of interacting individuals and lags (neither perfect coordination nor complete
irrelevance) among such movements.
Adachi (2003) raised the objection that the term“society” is commonly limited to individuals of one
species. She described the mixed-species association of
cercopithecid monkeys in the Taï Forest in order todiscuss fission-fusion across species and their interspecific interactions. A mixed-species association does
not result in a stable and constant social structure. In
her study, Adachi attempts to adopt the autopoiesis
theory of Kawamoto (1995) in order to describe such afugitive, momentary and ephemeral aspects of a society(for English introduction to autopoiesis theory, see
Maturana and Varela 1987). Although suchnon-structured (corresponding to Itani’s anti-structure)societies seen in mixed-species associations are often
difficult to treat with our language because of their lackof structure, Adachi argues they are essential in understanding what is regarded “social” in primate studies.
This is because what we actually experience as “social”
in our everyday life is not often structured but rather
non-structured as shown in the case of a child at the
beginning.
Nishie (2008) studied the interactions of Mahale
chimpanzees involved in arboreal ant fishing, and provided detailed descriptions of some events. Although
ant fishing is usually regarded as cultural tool-use, Nishie’s approach differed from that of current cultural
studies or social learning theories of primates, whichtacitly assume the transfer of information from aknowledgeable individual to an ignorant other. He reconsidered and deconstructed such transmission metaphors and instead introduced another epistemologicalstandpoint, action-practice model. He described dynamics of the social practices at ant-fishing scenes, andby doing so, discussed that some characters such as
attitude depending on others’ actions, moderate exploring proposition to others, and direct reaction to suchpropositions, were important to realize such social
situation of ant-fishing as a cultural practice of chimpanzees. Such standpoint might widen the scope ofcultural primatology: cultural behaviors represented bytool use should not be treated only as a relationshipbetween the actor and the object (e.g., ants) connectedwith a tool. It should be reminded that each cultural
practice is embedded in ongoing social interactions inthe scene.

Quality of Interactions
Strictly speaking, a phenomenon occurs only once;
therefore, every phenomenon is unique. However, we
usually categorize some interactions into certain types
and develop appropriate terms for them. The labeledinteractions that we identify can often occur in a similar
fashion but differently in some contexts.
Sugawara (1980) studied the interactions of encounters among solitary male Japanese macaques at
Koshima Islet. He found that “agonistic” interactions
such as attack and mounting occurred more often in
triads than in dyads. This shows that the occurrence ofa particular type of interaction is dependent on thenumber of participants. Nakamura (2003), who studied
chimpanzee grooming, also found such a difference:
Males groomed more often in dyads and triads, whereas
females groomed more often in polyads of more than
five individuals. Although studies of social behavior
usually treat polyadic interaction by splitting it into
dyadic interactions and summarizing such decomposed
dyadic interactions, the abovementioned studies imply
that the number of participants at the scene affects atleast the quality of interactions.
Similar types of interactions are often adopted incompletely different contexts, for example, in play.
Bateson (1955) observed that “two monkeys engaged in
an interactive sequence of which the unit actions or
signals were similar to but not the same as those of
combat.” Although biting and hitting may be observedin play, “the playful nip denotes the bite, but it does not
denote what would be denoted by the bite.” Inspired by
Bateson’s theory, Hayaki conducted studies on social
play and other interactions among immature Japanesemonkeys (Hayaki 1983) and chimpanzees (Hayaki
1985; 1990).
Another example may be sexual interaction that is
not directly connected to reproduction. Kitamura(1986)
referredtointeractions
involving
non-reproductive genital contacts in bonobos as “fictional” (“kari no mono” in Japanese, for which there is
no appropriate equivalent word in English). In this case,fictional implies that the behaviors acquire different
characteristics although they still possess their originalfunctions. Bonobo sexual behaviors are closely related
to their original function of reproduction; however,such behaviors are often used outside the reproductive
context. Thus, Kitamura argued that the analysis basedon interactions as fictional occurrences should inevitably be separated from causal or psychological motive
theory, and the focus should be shifted to the analysis
of its formal characteristics.
The abovementioned studies often do not rely on
quantitative data only but instead often employ analyses of events or stories. In addition, because each author employs her/his own original style of discourse, it
is not easy to summarize the common features of thesestudies. However, the studies seem to share the samestance, namely, viewing society as a contingent anddynamic phenomenon rather than as a deterministic

world. Therefore, when these researchers use quantitative data, their categorization is often more subtle thanusual, and they tend to provide more than the usual
amount of data required for answering a particularquestion, in an attempt to describe the variations observed in various scenes. Standard researchers often
consider such tendencies to be redundant and difficult
to understand because such studies are not the usual
hypothesis-testing ones.
Such a descriptive style of research is more common in social sciences such as cultural and social anthropology or ethnomethodology. However, although
primatology also deals with society, there are very few
descriptive studies recently in the West. An exception is
the study by King (2004), who emphasized dynamic
system theory, nonlinear thinking, and qualitative research. Although the subtitle of this book is “nonvocal
communication in African great apes,” the use ofcommunication is not as narrow as the conventional
sense, in which case it is almost equivalent to thetransfer of information from one individual to another.
In her study, King uses communication to refer to themore dynamic, ever-changing, and emergent propertyof social interactions. A similar wider view with regard
to communication is also expressed and explored by
Japanese primatologists (e.g., Kitamura 1988; Hayaki
1988; Takahata 1997). Kitamura (1990) emphasized theimportance of interactional synchrony as the fundamental basis for communication and tried to further
elaborate his idea (Kitamura 1996, 1999) in order toconnect communication among nonhuman primates tothat among humans.

Problems and Critiques
As mentioned above, primate interaction studies inJapan attempt to approach primate sociality by placing
greater emphasis on qualitative descriptions of interactions. This does not imply that such studies do not
conduct quantitative analyses. In my understanding,currently, the only way to understand the niceties ofinteractions is through minute and careful description.
However, as discussed above, descriptive researches do
not permit easy generalizations because of the nature of
the individuality of phenomena. This was perhaps adifficult point to accept in the current field of evolutionary ecology, which usually aims at concise theorization and generalization of phenomena in the world ofanimals. Earlier, Japanese primatology easily transgressthe methodological agreement of natural sciences andeven employed the methodologies in social science.
This practice was repeatedly criticized even within
Japan. For example, in the very early stages of Japanese
primatology, Sasaki (1956) made the following criticism: “It seems to me that some of the basic concepts
formed by social scientists in the course of studying
human society have been too easily applied to naturalsociety (of monkeys)” (my translation). Similarly, morethan four decades later, Muroyama (1998) also offereda similar criticism: “The fundamental problem of tradi-tional Japanese primatology is the application of methodology or concepts of sociology or cultural anthropology to nonhuman primates” (my translation).
Such critiques are valid in the sense of austerity that
we should not easily employ anthropomorphism.
However, when we deal with the dynamism and qualityof social interactions and societies, some methodologies of social sciences can be of help. But why are suchmethodologies permitted to only one species of primates? When we try to observe the continuities of social phenomena among primates, why must we have toadhere to the distinction of human and nonhuman? Is
this not another form of anthropocentrism? Of course,
we cannot directly apply the methods of sociology or
cultural anthropology. It is plain that researchers greatly
depend on information obtained from verbal report insuch study domains, whereas primatologists can neverask their targets a question. When Itani (1985a) argued
that studies of primates need “not necessarily rely on
biological and reductionistic approaches but can establish original and unique methodologies and theories asa social science,” he may have been thinking beyond
simple anthropomorphism.
Lack of theory was also criticized within the fieldof Japanese primatology: “As primatology has flourished worldwide and novelty has decreased, it shouldbe emphasized that we are at a deadlock because of thelack of theory in Japanese primatology” (Takahata 1994,
my translation). With respect to the lack of theory, deWaal (2003) defended Japanese primatologists; however, it may be true that Japanese primatology could notpresent a theory in Sibatani’s (1999) sense, namely,
allowing its followers to investigate and mass-produce
articles within the framework without considering thevalidity of the framework itself. This should be understood within the context that in the Kyoto School: theories that were easily followed by many people were oflittle account; instead, it was demanded that each individual researcher establish his/her own research theory
from his/her own observation. Recently, Japanese researchers have begun more easily to accept and to follow dominant theories such as sociobiology and socioecology.
However, original theoretical considerations about
the sociality of nonhuman primates in relation to humans also exist in Japan: Kitamura (1982; 2002) treatedthe concept of incest avoidance observed in nonhumanprimates with respect to the famous theory by
Lévi-Strauss; he also discussed the origin of language
in connection with nonhuman communication (Kitamura 1999). Yamagiwa (1994) discussed the origin of
the human family from the perspective of gorilla societies; similarly, Sugawara (2002) has argued about theemotional connection of primates and humans; andKuroda, who had studied food sharing among bonobos(Kuroda 1984), developed his idea to explore the originof social rules or institutions without language (Kuroda
1999).
These theoretical considerations in addition to thoseby Imanishi and Itani (see above) are not easy to understand, and it should be noted that these researcherssometimes employed terms that were not from the fieldof biology and sometimes created their own terminology. It should also be noted that it is not very easy totheorize about purely social phenomena. This is related
to the fact that in human sociology, there is no single
central theoretical framework to explain the diverse
social phenomena. Because researchers themselves area part of society and because their research is closely
connected to society, the research becomes
self-referential and therefore, cannot be assessed in a
simple fashion.

Toward Understanding Dynamic Sociality
Today, the original and traditional Japanese primatology is losing status. In the name of globalization,
Japanese students are guided to write their first scientific paper in English and many of them do so (also see
Asquith 2000). Writing papers in English is useful for
attaining a wide range of readership and to expand
beyond the narrow academic world of Japan. However,since students do this without fully considering theunderlying theoretical background, and many of themsimply write papers that adhere to global trends. It appears that the abstruseness of the East is now being
eradicated; however, at the same time, the unique andoriginal views of the East are also disappearing.
Although it may not be a time to make a claim regarding the uniqueness of Japanese primatology, thedifferences in language and cultural background still
remain. In particular, it is difficult to describe minuteand subtle social interactions in languages other than
one’s mother tongue. Descriptions that are originallyrich in Japanese, once translated into English, can often
become platitudes and/or simplistic (Mori 1994) if thewriter does not have excellent English language skills.
Some quantitative data by Japanese primatologists may
be evaluated to an extent; however, ideas such as direct
focus on interaction itself are rarely understood byglobal academics. Unless they receive such acceptance(which implies that such papers may not be accepted ininternational journals), few researchers are seriously
willing to study such phenomena. I hope that this paper
has been able to express, even to a limited extent, someof the epistemology of interaction studies in Japanese
primatology, which is not part of the mainstream andcontinues to be sidelined.
If we accept that primates are social beings, primatology does not have to limit itself to biology (Itani
1985a), one of the natural sciences, or such a limit
should not be applicable with regard to the understanding of some aspects of primate sociality. Although there
is an increase in the evolutionary understanding of human behaviors and societies (e.g., Barkow et al. 1992),
few researchers would insist that human societies andsociality can be understood only in the context of biology. It is possible to have an academic domain for the
study of sociality in primatology or even in zoology.
Scholars are now beginning to accept that primatesand other nonhuman animals have their own cultures(e.g., McGrew 2004) and have proposed terms such as“cultural primatology” (de Waal 1999) and primate“ethnography” (Wrangham et al. 1994). In such a domain of studies, methods or concepts outside of biology
are sometimes employed and some descriptive studies
are permitted. Because primatologists understand therichness of each primate society, it may be time to focus on a field such as “primate sociology.”
Acknowledgments
The study was financially supported in part by grants fromJapanese MEXT (#16255007, #19255008 to T Nishida and#16770186 to MN) and the Global Environment Research
Fund (F-061) of the Ministry of the Environment, Japan. I
thank Drs. Akio Mori, William C. McGrew, Toshisada Nishida,and an anonymous reviewer for their constructive comments
and suggestions on the earlier version of the paper.

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