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The inhabitants of Tauwema village represent a traditionally living society. Altogether, 39 inhabitants belonging to seven families were included in this study. Families or people living in one household were preferentially chosen for monitoring particularly the effects of social zeitgebers and synchronization within families. They were observed continuously for 7 consecutive days using microelectronic actometers that register locomotor activity with a sampling period of 2 minutes and a resolution of 7 bit. The activity data obtained showed that in young infants circadian patterns develop out of ultradian components dominating in the first months of life. The rhythmicity of the adults was well-related to the natural light-dark cycle, combined with a strong social component which is reflected in a comparatively small intra- and inter-individual variability in the time of the end of the main sleep span in the morning, while the variability in the beginning of the main sleep period in the evening is much greater. The mean sleep duration of the younger infants (up to 11 months; n=4) varied between 9 and 12 h per day and that of the adults (n = 23) between 7 and 10 h. Gender-specific differences occurred in married couples with wives having a longer sleep duration in 7 out of 9 cases. [ABSTRACT FROM AUTHOR]

This paper compares various explanatory concepts of food sharing in humans. In many animal species, parents share food with their offspring, thus investing into the 50% of their own genes present in each child. Even in modern families of industrialised societies, there is a very significant flow of material goods from the parent to the offspring generation. Sharing food between reproductive partners is also easily explainable in evolutionary terms: „food for sex“ as male strategy is observed in some primate species. Sharing within one’s group in small-scale societies can be explained also as consequence of its members being actually rather closely related to each other; this, among others, gives credit to the concept of group selection which gains attention again after having been discarded by classic sociobiology. The ethos of individual and group sharing can quite readily be transferred to larger groups, i.e. a whole nation or, especially in the case of unusually devastating natural disasters, to members of other societies. Food sharing beyond genetic relationship or reproductive interest has been explained as „tit for tat“ and „reciprocal altruism“. Events of give and take, however, are, how the last example demonstrates, quite often non-symmetrical, i.e. one partner shares much more than the other. „Tolerated theft“, a behavioural trait in non-human primate species thought to be a stepping stone for the typical preparedness of humans to share, does not play a big role in traditional societies, which provide an important base to discuss the topic. The Trobriand Islanders, e.g., have a very complex system of sharing. In the years of competitive harvest, their yield of yam is distributed to close relatives, especially to fathers and elder brothers. The donors keep almost nothing for themselves, are however given as well, so that everybody has enough to live. High rank men receive a partly enormous surplus, by which their status is increased. Western farmers would find this generosity quite strange. It is one outcome of the human tendency to create bonds through food gifts. It is interesting, that Marcel Mauss has well described the power of the gift which generates a counter gift, but did not inquire evolutionary nor ontogenetic building blocks of the often very complex acts and rituals of giving and receiving one finds in all cultures. It seems reasonable to take an evolutionary position and argue that those of our ancestors who were generous and socially competent with a well-developed emphronesis (Theory of Mind) were preferred interaction and marriage partners and that this sexual selection was the ultimate mechanism spreading the motivations and behaviours involved in sharing. To counteract cheaters humans have a rather sharp perception to detect those who don’t play by the rules and a very strong motivation to punish them, even accepting, in doing so, high costs for themselves. This strongly disproves the idea that humans mainly act on rationale choice. Rather, we are endowed, one must conclude, with a very powerful, archaic sense of balanced social interaction, of fairness and justice. This raises the interesting question whether the laws governing social conduct, made by all cultures of the world, are contra or secundum naturam. For quite some time, in the wave of sociobiological thinking, the common stand was that humans are dangerously egoistic beings and that their antisocial instincts must be kept in check by powerful laws. As Irenäus Eibl-Eibesfeldt, the founder of human ethology as a discipline, has stated and as recent primatological and anthropological research has corroborated, humans are much more social than postulated by some authors. The Ten Commandments are built on not against basic human tendencies. Konrad Lorenz spoke of animals having “morally analogous” behaviours and was criticised for this. Modern research is rehabilitating him. The joy of sharing, a proximate behavioural set of motivation, is typical for our species. Notwithstanding expectations of economic and status gain this biopsychologically rooted tendency most likely is the engine driving the systems of do ut des, so marvellously developed in our species.

The Massim, a cultural region that includes the southeastern tip of mainland Papua New Guinea (PNG) and nearby PNG offshore islands, is renowned for a trading network called Kula, in which different valuable items circulate in different directions among some of the islands. Although the Massim has been a focus of anthropological investigation since the pioneering work of Malinowski in 1922, the genetic background of its inhabitants remains relatively unexplored. To characterize the Massim genomically, we generated genome-wide SNP data from 192 individuals from 15 groups spanning the entire region. Analyzing these together with comparative data, we found that all Massim individuals have variable Papuan-related (indigenous) and Austronesian-related (arriving ∼3,000 years ago) ancestries. Individuals from Rossel Island in southern Massim, speaking an isolate Papuan language, have the highest amount of a distinct Papuan ancestry. We also investigated the recent contact via sharing of identical by descent (IBD) genomic segments and found that Austronesian-related IBD tracts are widely distributed geographically, but Papuan-related tracts are shared exclusively between the PNG mainland and Massim, and between the Bismarck and Solomon Archipelagoes. Moreover, the Kula-practicing groups of the Massim show higher IBD sharing among themselves than do groups that do not participate in Kula. This higher sharing predates the formation of Kula, suggesting that extensive contact between these groups since the Austronesian settlement may have facilitated the formation of Kula. Our study provides the first comprehensive genome-wide assessment of Massim inhabitants and new insights into the fascinating Kula system., (© The Author(s) 2022. Published by Oxford University Press on behalf of Society for Molecular Biology and Evolution.)

Environmental parameters constrain the distributions of plant and animal species. A key question is to what extent does environment influence human behavior. Decreasing linguistic diversity from the equator towards the poles suggests that ecological factors influence linguistic geography. However, attempts to quantify the role of environmental factors in shaping linguistic diversity remain inconclusive. To this end, we apply Ecological Niche Modelling methods to present-day language diversity in New Guinea. We define an Eco-Linguistic Niche (ELN) as the range of environmental conditions present in the territory of a population speaking a specific language or group of languages characterized by common language traits. In order to reconstruct the ELNs, we used Papuan and Austronesian language groups, transformed their geographical distributions into occurrence data, assembled available environmental data for New Guinea, and applied predictive architectures developed in the field of ecology to these data. We find no clear relationship between linguistic diversity and ELNs. This is particularly true when linguistic diversity is examined at the level of language groups. Language groups are variably dependent on environment and generally share their ELN with other language groups. This variability suggests that population dynamics, migration, linguistic drift, and socio-cultural mechanisms must be taken into consideration in order to better understand the myriad factors that shape language diversity., Competing Interests: The authors have declared that no competing interests exist.

The island region at the southeastern-most tip of New Guinea and its inhabitants known as Massim are well known for a unique traditional inter-island trading system, called Kula or Kula Ring. To characterize the Massim genetically, and to evaluate the influence of the Kula Ring on patterns of human genetic variation, we analyzed paternally inherited Y-chromosome (NRY) and maternally inherited mitochondrial (mt) DNA polymorphisms in >400 individuals from this region. We found that the nearly exclusively Austronesian-speaking Massim people harbor genetic ancestry components of both Asian (AS) and Near Oceanian (NO) origin, with a proportionally larger NO NRY component versus a larger AS mtDNA component. This is similar to previous observations in other Austronesian-speaking populations from Near and Remote Oceania and suggests sex-biased genetic admixture between Asians and Near Oceanians before the occupation of Remote Oceania, in line with the Slow Boat from Asia hypothesis on the expansion of Austronesians into the Pacific. Contrary to linguistic expectations, Rossel Islanders, the only Papuan speakers of the Massim, showed a lower amount of NO genetic ancestry than their Austronesian-speaking Massim neighbors. For the islands traditionally involved in the Kula Ring, a significant correlation between inter-island travelling distances and genetic distances was observed for mtDNA, but not for NRY, suggesting more male- than female-mediated gene flow. As traditionally only males take part in the Kula voyages, this finding may indicate a genetic signature of the Kula Ring, serving as another example of how cultural tradition has shaped human genetic diversity.

In recent years, the fine arts, architecture, music and literature have increasingly been examined from the vantage point of human ethology and evolutionary psychology. In 2011 the authors formed the research group 'Ethology of the Arts' concentrating on the evolution and biology of perception and behaviour. These novel approaches aim at a better understanding of the various facets represented by the arts by taking into focus possible phylogenetic adaptations, which have shaped the artistic capacities of our ancestors. Rather than culture specificity, which is stressed e.g. by cultural anthropology and numerous other disciplines, universal human tendencies to perceive, feel, think and behave are postulated. Artistic expressive behaviour is understood as an integral part of the human condition, whether expressed in ritual, visual, verbal or musical art. The Ethology of the Arts-group's research focuses on visual and verbal art, music and built environment/architecture and is designed to contribute to the incipient interdisciplinarity in the field of evolutionary art research.

Laterality in handgrip strength was assessed by analyzing dynamometric data of the right and left hand in three samples of Lithuanian boys and girls aged 7-20 years. In addition, the influence of general physical training on the laterality of handgrip strength was explored in a sample of conscripts. A negative secular trend in handgrip strength of schoolchildren has been detected since 1965, and with increasing age, right-handedness has become more pronounced. Children that were ambidextrous (by grip strength) showed negative deviations in physical status more often than their right- or left-handed peers. During one year of physical training, the conscripts had a larger increase in grip strength of the left than in the right hand, and a marked shift in handgrip laterality toward left-handed and ambidextrous individuals was observed. The different impact of schooling and physical training on handgrip strength laterality might partly explain variations in the prevalence of handedness in different societies with divergent cultures and lifestyles (e.g., more or less sedentary)., (© 2013 New York Academy of Sciences.)

The negative bias accompanying the terms left and left-handers has long interested researchers. This paper examines a large number of languages of Indo-European and non-Indo-European origin for such biasing. One surprising outcome is that, within the Indo-European language family, the terms for right and left do not go back to one set of antonyms but have their etymological roots in a number of different core semantic concepts. As in the non-Indo-European languages, right is almost always thought of positively, whereas left is negatively connotated. This is interpreted as the outcome of a universal human evaluation process, partly based on the principle of embodiment. The terms for right never have, in any of the examined languages, a negative bias; the words for left, usually never positively biased, were turned into euphemisms in three language groups (Scandinavian, Greek, and Avestan). On one interpretation, this seems to be an act of historical political correctness, corroborating the negative attitude cultures have for left-handers, very likely an outcome of discrimination of minorities., (© 2013 New York Academy of Sciences.)

The evolution of handedness in human populations has intrigued scientists for decades. However, whether handedness really affects Darwinian fitness is unclear and not yet studied in a non-industrial society where selection pressures on health and handedness are likely to be similar to the situation in which handedness has evolved. We measured both hand preference and asymmetry of hand skill (speed of fine motor control, measured by a pegboard task, and accuracy of throwing), as they measure different aspects of handedness. We investigated the associations between both the direction (left versus right) and strength (the degree to which a certain preference or asymmetry in skill is manifested, independent of the direction) of handedness. We analyzed to what extent these measures predict the number of offspring and self-reported illness in a non-industrial society in Papua, Indonesia. As it is known that body height and fitness are correlated, data on body height was also collected. Due to low numbers of left-handers we could not investigate the associations between direction of hand preference and measures of Darwinian fitness. We found a positive association between strength of asymmetry of hand skill (pegboard) and the number of children men sired. We also found a positive association for men between strength of hand preference and number of children who died within the first three years of life. For women we found no such effects. Our results may indicate that strength of handedness, independent of direction, has fitness implications and that the persistence of the polymorphism in handedness may be ascribed to either balancing selection on strength of asymmetry of hand skill versus strength of hand preference, or sexual antagonistic selection. No relationships between health and handedness were found, perhaps due to disease related selective disappearance of subjects with a specific handedness.

Considerable variation in the frequency of left-handedness between cultures has been reported, ranging from 0.5 to 24%. This variation in hand preference may have evolved under natural or cultural selection. It has been suggested that schooling affects handedness but as in most human societies only a selected and minor part of the population does not attend school this is difficult to test. We investigated to what extent schooling affects both hand preference and asymmetry in hand skill in a non-industrial population in the highlands of New Guinea. This provided unique opportunities because of the relatively recent establishment of a primary school in this population, and where people still live a non-industrial traditional life reflecting conditions in which handedness may have evolved. We interviewed 620 inhabitants (aged 5-70 y) to collect demographic data and school history, tested hand preference on 10 ecologically relevant activities, and measured performance of each hand on three tasks (pegboard, grip force, ball throwing). Schooled individuals were overall faster in fine motor performance, had greater grip strength and greater throwing accuracy. This suggests that there is implicit selection on the fitter part of the population to enter school. Schooling is associated with hand preference, as schooled individuals were more likely to be extremely right-handed and less likely to be strongly right-handed, but not with asymmetry of hand skill (controlled for sex and age). Developmental plasticity in hand preference but not skill asymmetry, and the weak correlations between hand preference and hand skill asymmetry indicate that they represent different aspects of brain lateralization. Furthermore, the weak correlations between hand preference and hand skill asymmetry leave room for moderating factors such as schooling, sex and age to have a differential effect on hand preference and hand skill, and each needs to be studied in its own right., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Introduction: Nausea and vomiting during pregnancy (NVP) constitute a frequent and often highly unpleasant syndrome during the sensitive period of early pregnancy, which has been intensively investigated. However, many questions remain unanswered, particularly the counterintuitive association with a better pregnancy outcome. Under these circumstances our functional concept to interpret NVP as an evolutionary mechanism of complex adaptation to early pregnancy seems promising., Method: In this cross-cultural study data were collected from 565 mothers, who had given birth recently in South Africa, Guatemala and Germany, using a standardised questionnaire interview., Results: There was a cross-culturally similar prevalence and clinical presentation of NVP, showing a high degree of subjective suffering. We found evidence supporting a multifactoral aetiology of biological, psychological and sociological factors. Likewise, NVP seems to have multiple effects, concerning nutrition, behaviour, perception, psychology and social support., Discussion and Conclusion: Our new and previously existing data support the idea that NVP has been selected for by evolution, as a functional adaptation to vulnerable early pregnancy, which benefits mother and child. This assumption is supported by the correlation of NVP with a better foetal prognosis, the cross-culturally high prevalence and a favorable relation of low biological costs versus high effects. The benefit of NVP could be realised by nutritional change, increased social support, more passive and careful behaviour, earlier recognition of pregnancy and a positive influence on foetal development. To understand the functionality of NVP, one needs to consider the complex somato-psychoemotional interplay in the context of an environment of evolutionary adaptedness (EEA)., (Georg Thieme Verlag KG Stuttgart-New York.)

Postpartum dysphoria (Baby Blues) is a puerperal-disease of mothers who have recently given birth; its prevalence in western industrialized countries ranges from 26 to 85% The baby-blues may begin during the first week after birth, lasts a few days and disappears without any medical treatment. Therefore there is still little research dealing with this phenomenon. The present study was carried out in Brixen, Italy, in the framework of the international Munich-Postpartum-Project and was done by means of a questionnaire. It showed that these women who had to face an insecure social environment after hospital discharge, had symptoms of a dysphoria. For that reason the Blues seems to be a phenomenon of socially distressed women.

The genetic ancestry of Polynesians can be traced to both Asia and Melanesia, which presumably reflects admixture occurring between incoming Austronesians and resident non-Austronesians in Melanesia before the subsequent occupation of the greater Pacific; however, the genetic impact of the Austronesian expansion to Melanesia remains largely unknown. We therefore studied the diversity of nonrecombining Y chromosomal (NRY) and mitochondrial (mt) DNA in the Admiralty Islands, located north of mainland Papua New Guinea, and updated our previous data from Asia, Melanesia, and Polynesia with new NRY markers. The Admiralties are occupied today solely by Austronesian-speaking groups, but their human settlement history goes back 20,000 years prior to the arrival of Austronesians about 3,400 years ago. On the Admiralties, we found substantial mtDNA and NRY variation of both Austronesian and non-Austronesian origins, with higher frequencies of Asian mtDNA and Melanesian NRY haplogroups, similar to previous findings in Polynesia and perhaps as a consequence of Austronesian matrilocality. Thus, the Austronesian language replacement on the Admiralties (and elsewhere in Island Melanesia and coastal New Guinea) was accompanied by an incomplete genetic replacement that is more associated with mtDNA than with NRY diversity. These results provide further support for the "Slow Boat" model of Polynesian origins, according to which Polynesian ancestors originated from East Asia but genetically mixed with Melanesians before colonizing the Pacific. We also observed that non-Austronesian groups of coastal New Guinea and Island Melanesia had significantly higher frequencies of Asian mtDNA haplogroups than of Asian NRY haplogroups, suggesting sex-biased admixture perhaps as a consequence of non-Austronesian patrilocality. We additionally found that the predominant NRY haplogroup of Asian origin in the Admiralties (O-M110) likely originated in Taiwan, thus providing the first direct Y chromosome evidence for a Taiwanese origin of the Austronesian expansion. Furthermore, we identified a NRY haplogroup (K-P79, also found on the Admiralties) in Polynesians that most likely arose in the Bismarck Archipelago, providing the first direct link between northern Island Melanesia and Polynesia. These results significantly advance our understanding of the impact of the Austronesian expansion and human history in the Pacific region.

To investigate the paternal population history of New Guinea, 183 individuals from 11 regional populations of West New Guinea (WNG) and 131 individuals from Papua New Guinea (PNG) were analyzed at 26 binary markers and seven short-tandem-repeat loci from the nonrecombining part of the human Y chromosome and were compared with 14 populations of eastern and southeastern Asia, Polynesia, and Australia. Y-chromosomal diversity was low in WNG compared with PNG and with most other populations from Asia/Oceania; a single haplogroup (M-M4) accounts for 75% of WNG Y chromosomes, and many WNG populations have just one Y haplogroup. Four Y-chromosomal lineages (haplogroups M-M4, C-M208, C-M38, and K-M230) account for 94% of WNG Y chromosomes and 78% of all Melanesian Y chromosomes and were identified to have most likely arisen in Melanesia. Haplogroup C-M208, which in WNG is restricted to the Dani and Lani, two linguistically closely related populations from the central and western highlands of WNG, was identified as the major Polynesian Y-chromosome lineage. A network analysis of associated Y-chromosomal short-tandem-repeat haplotypes suggests two distinct population expansions involving C-M208--one in New Guinea and one in Polynesia. The observed low levels of Y-chromosome diversity in WNG contrast with high levels of mtDNA diversity reported for the same populations. This most likely reflects extreme patrilocality and/or biased male reproductive success (polygyny). Our data further provide evidence for primarily female-mediated gene flow within the highlands of New Guinea but primarily male-mediated gene flow between highland and lowland/coastal regions.

To investigate the origins and relationships of Australian and Melanesian populations, 611 males from 18 populations from Australia, Melanesia, and eastern/southeastern Asia were typed for eight single-nucleotide polymorphism (SNP) loci and seven short tandem-repeat loci on the Y chromosome. A unique haplotype, DYS390.1del/RPS4Y711T, was found at a frequency of 53%-69% in Australian populations, whereas the major haplotypes found in Melanesian populations (M4G/M5T/M9G and DYS390.3del/RPS4Y711T) are absent from the Australian populations. The Y-chromosome data thus indicate independent histories for Australians and Melanesians, a finding that is in agreement with evidence from mtDNA but that contradicts some analyses of autosomal loci, which show a close relationship between Australian and Melanesian (specifically, highland Papua New Guinean) populations. Since the Australian and New Guinean landmasses were connected when first colonized by humans > or =50,000 years ago but separated some 8,000 years ago, a possible way to reconcile all the genetic data is to infer that the Y-chromosome and mtDNA results reflect the past 8,000 years of independent history for Australia and New Guinea, whereas the autosomal loci reflect the long preceding period of common origin and shared history. Two Y-chromosome haplotypes (M119C/M9G and M122C/M9G) that originated in eastern/southeastern Asia are present in coastal and island Melanesia but are rare or absent in both Australia and highland Papua New Guinea. This distribution, along with demographic analyses indicating that population expansions for both haplotypes began approximately 4,000-6,000 years ago, suggests that these haplotypes were brought to Melanesia by the Austronesian expansion. Most of the populations in this study were previously typed for mtDNA SNPs; population differentiation is greater for the Y chromosome than for mtDNA and is significantly correlated with geographic distance, a finding in agreement with results of similar analyses of European populations.

Background: Two competing hypotheses for the origins of Polynesians are the 'express-train' model, which supposes a recent and rapid expansion of Polynesian ancestors from Asia/Taiwan via coastal and island Melanesia, and the 'entangled-bank' model, which supposes a long history of cultural and genetic interactions among Southeast Asians, Melanesians and Polynesians. Most genetic data, especially analyses of mitochondrial DNA (mtDNA) variation, support the express-train model, as does linguistic and archaeological evidence. Here, we used Y-chromosome polymorphisms to investigate the origins of Polynesians., Results: We analysed eight single nucleotide polymorphisms (SNPs) and seven short tandem repeat (STR) loci on the Y chromosome in 28 Cook Islanders from Polynesia and 583 males from 17 Melanesian, Asian and Australian populations. We found that all Polynesians belong to just three Y-chromosome haplotypes, as defined by unique event polymorphisms. The major Y haplotype in Polynesians (82% frequency) was restricted to Melanesia and eastern Indonesia and most probably arose in Melanesia. Coalescence analysis of associated Y-STR haplotypes showed evidence of a population expansion in Polynesians, beginning about 2,200 years ago. The other two Polynesian Y haplotypes were widespread in Asia but were also found in Melanesia., Conclusions: All Polynesian Y chromosomes can be traced back to Melanesia, although some of these Y-chromosome types originated in Asia. Together with other genetic and cultural evidence, we propose a new model of Polynesian origins that we call the 'slow-boat' model: Polynesian ancestors did originate from Asia/Taiwan but did not move rapidly through Melanesia; rather, they interacted with and mixed extensively with Melanesians, leaving behind their genes and incorporating many Melanesian genes before colonising the Pacific.

The human species is an optimized product of evolution. This realization and knowledge of the highly sensitive and sensible biocybernetical processes in our bodies is now largely out of sight in modern medicine. To develop an evolutionary and cross-cultural perspective of human life and its biological, psychic and social conditions is therefore particularly important for the health sciences. Birth behaviour, intensive care for premature babies, post-partum dysphoria, sudden infant death, hip dysplasia, cry babies, eating disorders, stress-induced diseases, depression, ageing and dying serve as examples to sketch this new approach. It may probably facilitate diagnostic and therapeutic schemes which will be better adapted to human needs and capacities and can, therefore, be more successful than the ones in the past.

Mitochondrial DNA (mtDNA) analysis has proved useful in studies of recent human evolution and the genetic affinities of human groups of different geographical regions. As part of an extensive survey of mtDNA diversity in present-day Pacific populations, we obtained sequence information of the hypervariable mtDNA control region of 452 individuals from various localities in the western Pacific. The mtDNA types fell into three major groups which reflect the settlement history of the area. Interestingly, we detected an extremely rare point mutation at high frequency in the small island of Nguna in the Melanesian archipelago of Vanuatu. Phylogenetic analysis of the mtDNA data indicated that the mutation was present in individuals of separate mtDNA lineages. We propose that the multiple occurrence of a rare mutation event in one isolated locality is highly improbable, and that recombination between different mtDNA types is a more likely explanation for our observation. If correct, this conclusion has important implications for the use of mtDNA in phylogenetic and evolutionary studies.

Present-day Pacific islanders are thought to be the descendants of Neolithic agriculturalists who expanded from island South-east Asia several thousand years ago. They speak languages belonging to the Austronesian language family, spoken today in an area spanning half of the circumference of the world, from Madagascar to Easter Island, and from Taiwan to New Zealand. To investigate the genetic affinities of the Austronesian-speaking peoples, we analysed mitochondrial DNA, HLA and Y-chromosome polymorphisms in individuals from eight geographical locations in Asia and the Pacific (China, Taiwan, Java, New Guinea highlands, New Guinea coast, Trobriand Islands, New Britain and Western Samoa). Our results show that the demographic expansion of the Austronesians has left a genetic footprint. However, there is no simple correlation between languages and genes in the Pacific.

We have identified a new T-->C transition on the human Y chromosome. C-allele chromosomes have been found only in a subset of the populations from Asia and northern Europe and reach their highest frequencies in Yakut, Buryats, and Finns. Examination of the microsatellite haplotypes of the C-allele chromosomes suggests that the mutation occurred recently in Asia. The Y chromosome thus provides both information about population relationships in Asia and evidence for a substantial paternal genetic contribution of Asians to northern European populations such as the Finns.

Pain has important biomedical, socioanthropological, semiotic, and other facets. In this contribution pain and the expression of pain are looked at from the perspective of evolutionary biology, utilizing, among others, cross-cultural data from field work in Melanesia. No other being cares for sick and suffering conspecifics in the way humans do. Notwithstanding aggression and neglect, common in all cultures, human societies can be characterized as empathic, comforting, and promoting the health and sell-being of their members. One important stimulus triggering this caring response in others is the expression of pain. The nonverbal channel of communication, particularly certain universal--i.e., culture-independent facial expressions, gestures, and body postures, convey much of the message from the pain-stricken person to the group. These behaviors signal the person's physical and psychical pain, sadness, grief, and despair in ways very similar to the signs given by infants and small children: the body loses tonus and sinks or drops to the ground, the gestures are those of helplessness. Pain and grief may be so strong that control is lost not only over the body's posture but also over the mind's awareness. In such cases the afflicted person may carry out actions endangering himself or others. In general, these behavior patterns resemble those of infants in situations of distress and danger, and it is not surprising that the response of the members of the group is basically parental: taking care, assisting and consoling. Perceptive and behavioral patterns which developed in the course of avian and mammalian phylogeny to serve the well-being of the young have proven, as was shown by Eibl-Eibesfeldt (1989), to be powerful building blocks for actions in other spheres of human interaction. Love is one such field, the reactions to a conspecific suffering pain is another.

Sleep/activity patterns were continuously registered using microelectronic actometers on inhabitants of Tauwema (Papua New Guinea) who represent a traditionally living society. Results of analysis of parent-infant interactions of 4 families with infants of 1, 2, 5, and 11 months of age are presented. Results of power spectral analysis suggest that time patterns of mother-infant interactions are changing with the infants AE age. Consequences of this developmental process are discussed.