Infant Chimpanzees Research Articles

Preference for human direct gaze in infant chimpanzees ( Pan troglodytes)

We studied gaze perception in three infant chimpanzees ( Pan troglodytes), aged 10–32 weeks, using a two-choice preferential-looking paradigm. The infants were presented with two photographs of a human face: (a) with the eyes open or closed, and (b) with a direct or an averted gaze. We found that the chimpanzees preferred looking at the direct-gaze face. However, in the context of scrambled faces, the infants showed no difference in gaze discrimination between direct and averted gazes. These findings suggest that gaze perception by chimpanzees may be influenced by the surrounding facial context. The relationship between gaze perception, face processing, and the adaptive significance of gaze perception are discussed from an evolutionary perspective.

Book Review: Infant Chimpanzee and Human Child. A Classic 1935 Comparative Study of Ape Emotions and Intelligence

Book Review: Infant Chimpanzee and Human Child. A Classic 1935 Comparative Study of Ape Emotions and Intelligence

Infant chimpanzee and human child: a classic 1935 comparative study of ape emotions and intellegence

Infant chimpanzee and human child: a classic 1935 comparative study of ape emotions and intellegence

The Emotional Ape

Infant Chimpanzee and Human Child A Classic 1935 Comparative Study of Ape Emotions and Intelligence. N. N. Ladygina-Kohts. Edited by Frans B. M. de Waal. Oxford University Press, New York, 2002. 468 pp. $65. ISBN 0-19-513565-2. Series in Affective Science. In this work, which originally appeared as a memoir of Moscow's Darwin Museum, the author compares the development of a chimpanzee and her son in terms of inborn tendencies, emotions, play, and habits.

Erratum to: An infant chimpanzee (Pan troglodytes) follows human gaze

Erratum to: An infant chimpanzee (Pan troglodytes) follows human gaze

An infant chimpanzee (Pan troglodytes) follows human gaze.

The ability of non-human primates to follow the gaze of other individuals has recently received much attention in comparative cognition. The aim of the present study was to investigate the emergence of this ability in a chimpanzee infant. The infant was trained to look at one of two objects, which an experimenter indicated by one of four different cue conditions: (1) tapping on the target object with a finger; (2) pointing to the target object with a finger; (3) gazing at the target object with head orientation; or (4) glancing at the target object without head orientation. The subject was given food rewards independently of its responses under the first three conditions, so that its responses to the objects were not influenced by the rewards. The glancing condition was tested occasionally, without any reinforcement. By the age of 13 months, the subject showed reliable following responses to the object that was indicated by the various cues, including glancing alone. Furthermore, additional tests clearly showed that the subject's performance was controlled by the "social" properties of the experimenter-given cues but not by the non-social, local-enhancing peripheral properties.

Object manipulation in infant bonobos and gorillas

This study aimed to examine object manipulation in 2 to 4-year-old hand-reared infant African great apes, two bonobos and three gorillas. Humans and the great apes differ from other primate species in terms of their ability to use tools. Orienting manipulation (or combinatory manipulation), especially object-to-object manipulation, is considered to be a precursor of tool use. Although developmental changes in object manipulation that lead toward tool use have been investigated in chimpanzees, studies concerning bonobos and gorillas are extremely scarce. We observed free play in ape infants manipulating three kinds of objects: wooden blocks, nesting cups, and rings and a stalk. The size of the behavioral repertoire was measured by focusing on four variables: body parts used, number of objects manipulated, motor patterns, and types of orienting manipulation. Both species showed orienting manipulation (or combinatory manipulation) comparable to chimpanzee infants of similar ages. The gorillas' repertoire included fewer behaviors involving the use of the foot than the bonobos'. They showed the tendency of manipulating single object not in a single motor pattern but in multiple motor patterns.

Leaf-folding behavior for drinking water by wild chimpanzees (Pan troglodytes verus) at Bossou, Guinea.

The use of leaves for drinking water by wild chimpanzees (Pan troglodytes verus) at Bossou, Guinea, was observed intensively. The natural hollow of a tree, used by chimpanzees, was filled up with fresh water every morning. Seventy episodes of leaf-using behavior by 14 chimpanzees were directly observed and video-recorded. The chimpanzees at Bossou most frequently (70.3%) used a particular kind of leaf, Hybophrynium braunianum as tool material. The chimpanzees folded one or more leaves in the mouth. This technique, "leaf folding", was observed more frequently (57.9 %) than "leaf sponge" or "leaf spoon". Chimpanzees began to perform this behavior at about 2.5years old. Infant chimpanzees showed more frequent observations of others (especially their mothers) using leaves before trying to drink water with leaves. Both observation and trial and error might be necessary for the acquisition of this tool-use behavior.

Development of combinatory manipulation in chimpanzee infants (Pan troglodytes).

I made systematic observations of three infant chimpanzees aged 2-4 years, who participated in a series of diagnostic tests of combinatory manipulation. The tasks were stacking blocks, seriating nesting cups, and inserting an object into the corresponding hole in a plate or a box. These tasks were originally devised for developmental diagnosis of human infants. The chimpanzee infants displayed combinatory manipulation comparable to that of 1-year-old human infants. Common motor characteristics were observed across the tasks, namely "repetition" of actions, "adjustment" of actions, "reversal" of actions, and "shifts" of attention. Humans and chimpanzees share these actions when manipulating multiple objects to complete a task. Repetition, adjustment, and reversal of actions and shifts of attention underlie higher levels of cognition common to both species.

Psychotherapy and the single synapse: the impact of psychiatric thought on neurobiological research. 1979.

THE title of this lecture is at best premature and more likely absurd, but I have adopted it for two reasons. In the first place, I want to emphasize the continuing tension within psychiatry betwee...

Dynamic comparison of the development of combinatory manipulations between chimpanzee and human infants

I present my observations of combinatory manipulations by three infant chimpanzees in a series of test tasks. Common characteristics of motor patterns were observed across the tasks between both infant chimpanzees and 1-year-old infants. Based on the results, I point out that comparative approach can illuminate Thelen et al.'s arguments.

The 1/3 power law in spontaneous movements of limbs of human and chimpanzee infants for the first few months of age

The 1/3 power law in spontaneous movements of limbs of human and chimpanzee infants for the first few months of age

Reaching into Thought: The Minds of the Great Apes

1. Exploring the minds of the great apes: Issues and controversies Anne E. Russon and Kim A. Bard Part I. The Scope of Great Ape Intelligence: 2. Chimpanzees and capuchin monkeys: Comparative cognition James R. Anderson 3. Acting and understanding: tool use revisited through the minds of capuchin monkeys Elisabetta Visalberghi and Luca Limongelli 4. Consolation, reconciliation, and a possible cognitive difference between macaques and chimpanzees Frans B.M. de Waal and Filippo Aureli 5. The misunderstood ape: Cognitive skills of the gorilla Richard W. Byrne 6. Ostensive behavior in great apes: the role of eye contact Juan Carlos Gomez 7. Imitation in everyday use: matching and rehearsal in the spontaneous imitation of rehabilitant orangutans Anne E. Russon 8. 'More is less': the elicitation of rule-governed resource distribution in chimpanzees Sarah T. Boysen 9. Tool-using behavior in wild Pan paniscus: Social and ecological considerations Ellen J. Ingmanson 10. Comparison of chimpanzee material culture between Bossou and Nimba, West Africa Tetsuro Matsuzawa and Gen Yamakoshi Part II. Organization of Great Ape Intelligence: Development, Culture and Evolution: 11. Influences on development in infant chimpanzees: Enculturation, temperament and cognition Kim A. Bard and Kathryn H. Gardner 12. Heterochrony and the evolution of primate cognitive development Jonas Langer 13. Simon says: The development of imitation in an enculturated orangutan H. Lyn Miles, Robert W. Mitchell and Stephen E. Harper 14. Imitation, pretense, and mindreading: secondary representation in comparative primatology and developmental psychology? Andrew Whiten 15. Self-awareness and self-knowledge in humans, apes and monkeys Daniel Hart and Mary Pat Karmel 16. Apprenticeship in tool-mediated extractive foraging: the origins of imitation, teaching and self-awareness in great apes Sue Taylor Parker 17. The effect of humans on the cognitive development of apes Josep Call and Michael Tomasello 18. Three approaches for assessing chimpanzee culture Christophe Boesch 19. On the wild side of culture and cognition in the great apes Sue Taylor Parker and Anne E. Russon Index.

ESSAYS ON SCIENCE AND SOCIETY: Learning from the Chimpanzees: A Message Humans Can Understand

ESSAYS ON SCIENCE AND SOCIETY: Learning from the Chimpanzees: A Message Humans Can Understand

Safety and immunogenicity of HIV-1 DNA constructs in chimpanzees

A global effort to control the HIV epidemic is likely to rely heavily on immunization strategies. As our closest genetic relative, the chimpanzee provides the most important model for preclinical safety and immunogenicity studies. We have immunized adult, pregnant and infant chimpanzees with our plasmid vaccines. We have found these vaccines to be safe and well tolerated in all of these groups. The same vaccines have induced both humoral and cellular immunity in each instance.

Ethological study of early language

Sign language studies of cross-fostered chimpanzees measure the effect of special rearing conditions on the development of very young chimpanzees. Cross-fostered chimpanzees, like human children, develop gradually in a process that takes many years. Here we discuss details of the procedure, the overlap between human and chimpanzee infants in the contents of the first 50-item vocabularies, and the ways in which the signs of the chimpanzees exhibit the fuzziness of natural language categories. We also compare the cross-fostering approach with more traditional modular approaches to the study of language-like behavior in nonhuman animals.

Maternal influences on the development of hand preference in infant chimpanzees

Lymphocyte proliferation responses and natural killer cell activity were evaluated in 35 juvenile rhesus monkeys derived from five different rearing conditions. Nursery-reared monkeys had proliferation responses which were significantly higher than those of mother-reared subjects. Reexamination of the nursery-reared monkeys 1.5 years later indicated that an abnormally high response to concanavalin A was still evident at 2.5 years of age, but both PHA and PWM responses had shown an age-appropriate decrease into the normal range for this species. Proliferation responses in monkeys that had been weaned early from their mothers at 6 months of age were also higher than values for control monkeys that remained with their mothers, but below those of the nursery-reared monkeys. In contrast, monkeys that had received multiple separations from the mother between 3 and 7 months of age showed lymphocyte proliferation responses that were below normal. These results indicate that early rearing conditions can have a lasting effect on certain immune responses in the developing primate.

Neonatal neurobehavioral correlates of lateral bias and affect in infant chimpanzees (pan troglodytes)

In this study, I extend previous findings of population‐level asymmetries in lateral bias of multiple behavioral measures in infant chimpanzees. Moreover, I propose that different neurobehavioral mechanisms are associated with different behavioral measures. A longitudinal design was employed to assess neonatal neurobehavioral integrity, lateral bias at 3 months old, and lateral bias and affect at 9 to 10 months old. Approximately half of the sample was raised under standard nursery conditions (females, n = 9; males, n = 11), and the other half was raised in a “responsive care” nursery designed to promote species‐typical chimpanzee development (females, n = 9; males, n = 8). Significant right biases were confirmed for hand‐to‐mouth self‐calming behavior. Significant left biases were found in grasping of objects (at 9–10 months old). Hand‐to‐hand grasping, reflexive stepping, head posture while sleeping in a supine position, and defensive swipes were individually lateralized rather than population level biased. Neonatal neurobehavioral assessments were found to be significantly associated with lateral bias both at 3 months and at 9 to 10 months old. Arousal at 2 days of age was negatively correlated with hand‐to‐mouth bias, motor performance at 2 days old was positively correlated with hand‐to‐hand bias, and orientation performance at 30 days of age was positively correlated with head bias. The lateral bias in touching and grasping objects at 9 to 10 months of age was positively correlated with head bias by 3 months of age and with State Regulation at 2 days of age. Affective behavior at 9 to 10 months old was correlated with defensive bias at 3 months and with muscle tone at 2 days of age. Rearing environment, gender, and emotional reactivity were found to influence lateral bias. These findings support the hypothesis that different asymmetric behaviors, even if lateralized to the same direction, may reflect different biological processes and different functional mechanisms.

Inferring the Geographic Origins of “Refugee” Chimpanzees in Uganda from Mitochondrial DNA Sequences

Wild chimpanzee populations in Africa are rapidly declining due to deforestation, mining, and other practices that destroy chimpanzee habitat (Hamilton 1981; Struhsaker 1981; Hamilton 1984; Weber 1987; Teleki 1989; Howard 1991; Harcourt 1996). The hunting of chimpanzees for food and for trade on the international pet market exacerbates this trend. The pet trade has been particularly damaging; at least 10 chimpanzee infants die for every one that survives to its final destination (Teleki 1989). A secondary consequence of these threats is the proliferation of refugee chimpanzee populations. Increasing numbers of confiscated chimpanzees are being crowded into underftnded zoos and rehabilitation centers. In most countries in which chimpanzees live, conservation resources are desperately scarce. Knowing the principal areas from which chimpanzees are being captured could help governments direct conservation efforts and distribute law-enforcement resources optimally. Determining the origins of captive chimpanzees could also help with reintroduction efforts. Reintroduction is generally problematic (Campbell 1980) and is relatively unexplored as a prospect for chimpanzees. Nevertheless, individuals could in theory be reintroduced to their natal populations if these could be determined. More realistically, entire captive populations could be relocated to islands or to ecologically suitable but unoccupied mainland habitats (e.g., forests from which chimpanzees have become extinct). Knowing the geographic origins of captive chimpanzees would be invaluable for

Reviewed Article: The death of an infant chimpanzee at Bossou, Guinea

Reviewed Article: The death of an infant chimpanzee at Bossou, Guinea