Adult-infant food transfer in common marmosets: an experimental study

Infant marmosets and tamarins obtain solid food items from adults during and after the time of weaning. In addition to providing nutrients, food transfers may provide infants with the opportunity to learn about diet. The aim of this study was to investigate patterns of begging and food transfer in captive groups of common marmosets during tests with 1) palatable novel food, 2) unpalatable novel food, and 3) familiar food. Infants may gain an opportunity to learn about diet breadth by preferentially begging for novel rather than familiar items, while adults may facilitate infant learning by differing in their willingness to transfer food depending upon the food's novelty or palatability. In this study, infants exhibited more interest and begging with novel food items than with familiar ones. However, food transfers were not more likely to occur with novel foods than with familiar ones, and in fact adults were more likely to refuse infant begging attempts with novel foods. The palatability of the food also did not influence the rates of refusal and transfer: adults transferred palatable and unpalatable novel foods with similar frequencies. These results suggest that infant marmosets gain an opportunity to learn about diet breadth by begging for novel foods, but adults do not preferentially transfer novel or palatable food items.     

Breeding orangutans at Perth Zoo: Twenty years of appropriate husbandry

The Perth Zoo orang-utan husbandry strategy, which has been the foundation of 20 years of success in breeding, health, and longevity, is based on respect for the solitary arboreal nature of the species. The orang-utans are housed singly at night and fed only in their night dens. Diets are based on the weight and energy expenditure of the individuals. During the day they are housed singly or in very small groups that correspond in size and structure to wild population units. Adult males and females are only introduced for breeding purposes. Large climbing frames, which permit visual and vocal contact, dominate the day enclosures. A wide variety of manipulable objects are provided daily to enhance activity levels. Since 1968 there have been 21 births, 14 surviving infants, and no post-infancy deaths. All the mature animals are fertile. The major health problems of captive orang-utans and the most common causes of adult mortality have been absent from the colony. The husbandry method used has made it possible to record detailed reproductive data including complete menstrual cycle records for 8 females since 1981, the observation and quantification of cyclic proceptivity for all mature females, the calculation of 19 gestation periods, and the measurement of post-partum amenorrhea and interbirth intervals. Urinary hormone analysis is used regularly to confirm ovulation. A long-term study of the hormones mediating the development of secondary sexual characteristics in males was started in 1988. Captive orang-utans do not have a fertility problem, but the captive population is threatened by the unacceptably high mortality rate in young adults. This appears to be related to inappropriate husbandry methods. The most neglected aspect of orang-utan husbandry is natural social group size and structure.     

Comparative studies of social behavior in Callicebus and Saimiri: Behavioral and physiological responses of established pairs to unfamiliar pairs

The influences of cage size and novelty on the behavior of Galago senegalensis braccatus were examined in two captive groups (five adults and one immature per group) having similarly furnished but unequally sized cages. One group experienced expansion, and the other experienced contraction of space. Each group experienced the novelty of a new cage and return to its old cage. Exploration, nonsocial activity, and social sniffing behaviors were most frequent in both groups during the novelty phase independent of cage size. These behaviors remained elevated after return to the original cage. This pattern indicated that novelty, not space, was responsible for these behavioral changes. The increase in social sniffing indicated that group members may use olfactory cues to recognize each other, expecially when the setting is novel. In both groups, frequencies of displacements and chases were highest in the smaller space. Group differences in behavior prior to cage change also influenced a group's response to change.     

Stories and Selves: Managing the Self through Problem Solving in School

This study examines how a curriculum that aimed to instill in students a way of solving their everyday social problems instead became a site for replaying students' understandings of solutions approved by teachers and thus was limited in shaping their subjectivities. We draw on research in the ethnography of speaking, particularly in school settings, to refine current anthropological interest in the Foucauldian notion of technologies of the self. As a result, we highlight the contextual quality of practices, such as problem solving, used to manage the self.     

Learning set formation in a group of Guinea baboons (Papio papio): Importance of the behavioral variable measured

A recent report of one-trial learning in a group of saddle-back tamarins (Saguinus fuscicollis) conflicted with views of learning set formation based on traditional techniques employing isolated subjects. An experiment is reported in which a group of Guinea baboons (Papio papio) was given a series of discrimination and habit reversal tasks. Both one-trial learning and learning set formation occurred. Analysis of spatial behavior revealed that the group learned in a single trial to discriminate stocked from unstocked zones. Improvement in successes (reinforced “digging”) was progressive but not rapid, indicating learning set formation. It appears that outcomes depend on the behavioral variables chosen.     

The evolutionary basis of human social learning

Humans are characterized by an extreme dependence on culturally transmitted information. Such dependence requires the complex integration of social and asocial information to generate effective learning and decision making. Recent formal theory predicts that natural selection should favour adaptive learning strategies, but relevant empirical work is scarce and rarely examines multiple strategies or tasks. We tested nine hypotheses derived from theoretical models, running a series of experiments investigating factors affecting when and how humans use social information, and whether such behaviour is adaptive, across several computer-based tasks. The number of demonstrators, consensus among demonstrators, confidence of subjects, task difficulty, number of sessions, cost of asocial learning, subject performance and demonstrator performance all influenced subjects' use of social information, and did so adaptively. Our analysis provides strong support for the hypothesis that human social learning is regulated by adaptive learning rules.     

Selectivity in social and asocial learning: investigating the prevalence,effect and development of young children's learning preferences

Culture evolution requires both modification and faithful replication of behaviour, thus it is essential to understand how individuals choose between social and asocial learning. In a quasi-experimental design, 3- and 5-year-olds (176), and adults (52) were presented individually with two novel artificial fruits, and told of the apparatus'' relative difficulty (easy versus hard). Participants were asked if they wanted to attempt the task themselves or watch an experimenter attempt it first; and then had their preference either met or violated. A significant proportion of children and adults (74%) chose to learn socially. For children, this request was efficient, as observing a demonstration made them significantly quicker at the task than learning asocially. However, for 5-year-olds, children who selected asocial learning were also found to be highly efficient at the task, showing that by 5 years children are selective in choosing a learning strategy that is effective for them. Adults further evidenced this trend, and also showed selectivity based on task difficulty. This is the first study to examine the rates, performance outcomes and developmental trajectory of preferences in asocial and social learning, ultimately informing our understanding of innovation.     

The evolutionary roots of creativity: mechanisms and motivations

We consider the evolution of cognition and the emergence of creative behaviour, in relation to vocal communication. We address two key questions: (i) what cognitive and/or social mechanisms have evolved that afford aspects of creativity?; (ii) has natural and/or sexual selection favoured human behaviours considered ‘creative’? This entails analysis of ‘creativity’, an imprecise construct: comparable properties in non-humans differ in magnitude and teleology from generally agreed human creativity. We then address two apparent problems: (i) the difference between merely novel productions and ‘creative’ ones; (ii) the emergence of creative behaviour in spite of high cost: does it fit the idea that females choose a male who succeeds in spite of a handicap (costly ornament); or that creative males capable of producing a large and complex song repertoire grew up under favourable conditions; or a demonstration of generally beneficial heightened reasoning capacity; or an opportunity to continually reinforce social bonding through changing communication tropes; or something else? We illustrate and support our argument by reference to whale and bird song; these independently evolved biological signal mechanisms objectively share surface properties with human behaviours generally called ‘creative’. Studying them may elucidate mechanisms underlying human creativity; we outline a research programme to do so.     

Social foraging: individual learning and cultural transmission of innovations

We present two stochastic models of individual and social learningthat count the number of individuals exhibiting a learned, resource-producingtrait in a group of social foragers. The novelty of our modelingresults from incorporating the empirically based assumptionthat rates of both individual and social learning should dependon the frequency of the learned trait within the group. Whenresources occur as clumps shared by group members, a naive individual'sacquisition of the skill required for clump discovery/productionshould involve opposing processes of frequency dependence. Theopportunity to learn via cultural transmission should increasewith the trait's frequency, but the opportunity for learningindividually should decrease as the trait's frequency increases.The results of the model suggest that the evolution of the capacityfor cultural transmission may be promoted in environments wherescrounging at resource clumps inhibits rates of individual learning.     

The relative body weights of Bornean and Sumatran orangutans.

Although original field data suggested that the average Bornean orangutan weighed twice as much as the Sumatran ones, this is shown to be an error. The only statistically significant difference in weight is between males and females, regardless of geographical area or data source.     

Exploring the costs and benefits of social information use: an appraisal of current experimental evidence

Research on social learning has focused traditionally on whether animals possess the cognitive ability to learn novel motor patterns from tutors. More recently, social learning has included the use of others as sources of inadvertent social information. This type of social learning seems more taxonomically widespread and its use can more readily be approached as an economic decision. Social sampling information, however, can be tricky to use and calls for a more lucid appraisal of its costs. In this four-part review, we address these costs. Firstly, we address the possibility that only a fraction of group members are actually providing social information at any one time. Secondly, we review experimental research which shows that animals are circumspect about social information use. Thirdly, we consider the cases where social information can lead to incorrect decisions and finally, we review studies investigating the effect of social information quality. We address the possibility that using social information or not is not a binary decision and present results of a study showing that nutmeg mannikins combine both sources of information, a condition that can lead to the establishment of informational cascades. We discuss the importance of empirically investigating the economics of social information use.     

The phylogeny of the Trypanosomatidae: the molecular and morphological approaches

The results of comparative analysis of two phylogenetic trees of the trypanosomatids based on morphological and molecular characters are discussed. The morphological dendrogram was based on 33 ultrastructural characters, 6 light microscope characteristics and 8 biological characters. Molecular UPGMA dendrogram depicting differences (Dice distance) between examined trypanosomatids is based on the universally primed PCR polymorphisms. The general topology of both dendrograms are similar, with the Trypanosoma at the base. The genus Wallaceina appears to be monophyletic. In a contrary, the genera Leptomonas, Crithidia and Herpetomonas look like artificial groups according to both methods used. The cyst-forming homoxenous trypanosomatids from insects represent a monophyletic clade, which seems to be a separate genus. Two species of within genus Wallaceina are arranged as a separate subgenus.     

The evolution of animal 'cultures' and social intelligence

Decades-long field research has flowered into integrative studies that, together with experimental evidence for the requisite social learning capacities, have indicated a reliance on multiple traditions ('cultures') in a small number of species. It is increasingly evident that there is great variation in manifestations of social learning, tradition and culture among species, offering much scope for evolutionary analysis. Social learning has been identified in a range of vertebrate and invertebrate species, yet sustained traditions appear rarer, and the multiple traditions we call cultures are rarer still. Here, we examine relationships between this variation and both social intelligence--sophisticated information processing adapted to the social domain--and encephalization. First, we consider whether culture offers one particular confirmation of the social ('Machiavellian') intelligence hypothesis that certain kinds of social life (here, culture) select for intelligence: 'you need to be smart to sustain culture'. Phylogenetic comparisons, particularly focusing on our own study animals, the great apes, support this, but we also highlight some paradoxes in a broader taxonomic survey. Second, we use intraspecific variation to address the converse hypothesis that 'culture makes you smart', concluding that recent evidence for both chimpanzees and orangutans support this proposition.     

Dietary mixing in grasshoppers: Changes in acceptability of different plant secondary compounds associated with low levels of dietary protein (Orthoptera: Acrididae)

Schistocerca americanasixth-instar nymphs were examined for a change in diet acceptance, in which insects experiencing an unfavorable diet subsequently become predisposed to eat relatively less of that diet and more of diets with a novel flavor than they would had they previously fed on a more adequate diet. Insects were pretreated for 4 h on either low-protein (2 % wet wt) or higherprotein (4%) artificial diets flavored with a plant secondary compound (tomatine or rutin). They were then offered, in choice or no-choice tests, the lowprotein diet with the familiar or a novel (tomatine, rutin, or NHT) flavor. When tomatine was the familiar and rutin the novel flavor in a no-choice test, the insects previously fed low-protein diets took relatively long meals on the novel and relatively short meals on the familiar diets compared with the insects that had previously eaten higher-protein diets. A similar, but in this case considerably less pronounced and statistically nonsignificant, pattern existed in the reciprocal design experiment in which rutin was the familiar and tomatine the novel flavor. Similarly, insects fed low-protein diets flavored with rutin subsequently showed an increased relative preference for the novel flavor (NHT) in a choice test, compared with the high protein-pretreated insects. It is concluded that insects fed protein-deficient diets may subsequently show a preference for novel foods through different mechanisms, the importance of which may differ in different circumstances.     

The phylogeny of the Rosaceae

KALKMAN, C., 1988. The phylogemy of the Rosaceae. A phylogenetic (cladistic) analysis of Rosaceae (excluding Chrysobalanaceae and Neuradaceae) is presented, based on the postulated direction of evolution in 14 morphological characters. Tribes or smaller groups, considered to be holophyletic, are taken as operational units. Three possible cladograms, made by hand, are presented and discussed. One of them is, within the limits of the method, selected as the most plausible image of real history, but this cladogram is not fully resolved and contains much homoplasy. Also presented is a fourth cladogram, produced by computer (CAFCA program); it is of about the same quality.
It is not justified to base drastic alterations in current classification on the weak phylogenetic hypothesis. For the time being it seems better not to recognize any subfamilies, but only a number of tribes.
It is hypothesized that the family originated in West Gondwana. A diagram is presented in which the most plausible cladogram is combined with the present distribution, clarifying the postulated routes of migration.
The sistergroup of Rosaceae is far from evident. The Cunoniaceae are considered to be the most plausible choice.