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チンパンジーが協力して課題解決:2人で数字を順番に答える

November 01, 2017

2人で連続的に協力しなければ解決できない課題を考案し、チンパンジー2人が解決できるか観察することで、チンパンジーが役割交代をしながら連続的な協力行動をとることを、世界で初めて実証しました...

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チンパンジーがじゃんけんを学習
循環関係を理解する能力を備える

August 10, 2017

チンパンジーにじゃんけんの規則を教え、ルールを学習できるか調査したところ、7個体中5個体が完全に習得しました。ヒトの子どもにも同様の調査を行い、ヒトは約4歳で、じゃんけんのルールを習得できることがわかりました。 つまり、チンパンジーは、ヒトの4歳の子どもと同じくらい柔軟に循環関係を理解できる、認知能力があるということです...

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飼育チンパンジーの石器使用とオルドバイ渓谷から発見された初期人類の石器使用痕跡との比較

November 21, 2016

旧石器時代、初期人類はどのように石器を使用していたのでしょうか? その謎に迫るべく、飼育下のチンパンジーにオルドバイ渓谷から出土した石を使ってナッツを割ってもらいました。 結果...

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チンパンジーは、葉や果物のハリ、ツヤの違いを区別する

October 06, 2016

チンパンジーが葉や果物のハリ、ツヤのような瑞々しさの違いを見た目から区別できることを発見しました。また、その手がかりは色ではなく、輝度(明るさ)の分布の違いであることも示しました。これまで...

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「ほほえみ」の起源:ニホンザルの赤ちゃんにおける自発的微笑

August 02, 2016

生後4日から21日齢のニホンザルの赤ちゃん7個体を観察し、睡眠中に唇の端が上がる「自発的微笑」の詳細な分析を行いました。これまで、新生児にみられるこのような「微笑」はヒトの新生児期にのみ見られると考えられていましたが...

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A horse's eye view: size and shape discrimination compared with other mammals.
November 26, 2015

Mammals have adapted to a variety of natural environments from underwater to aerial and these different adaptations have affected their specific perceptive and cognitive abilities. This study used a computer-controlled touchscreen system to examine the visual discrimination abilities of horses, particularly regarding size and shape, and compared the results with those from chimpanzee, human and dolphin studies...,

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Great apes make anticipatory looks based on long-term memory of single events.
Seen Once, Never Forgotten   September 15, 2015

You don't have to be human to like a good horror flick, Kyoto scientists show Kyoto, Japan -- Having once seen the shower scene in Alfred Hitchcock's 1960 thriller Psycho, who can forget what happens next? And it turns out that aside from humans, great apes...,

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Social Attention in the Two Species of Pan: Bonobos Make More Eye Contact than Chimpanzees
June 19, 2015

African apes and humans have recently been found to share a genetic mutation that enables them to effectively metabolise ethanol1. The consumption of ethanol by modern-day humans is nearly universal, being found in every society with fermentable raw materials. However, aside from enforced ingestion in captive experiments or anecdotal observations in wild apes, the habitual and voluntary consumption of ethanol in this evolutionary radiation has been documented until now ...,

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Tools to tipple: ethanol ingestion by wild chimpanzees using leaf-sponges.
June 11, 2015

African apes and humans have recently been found to share a genetic mutation that enables them to effectively metabolise ethanol1. The consumption of ethanol by modern-day humans is nearly universal, being found in every society with fermentable raw materials. However, aside from enforced ingestion in captive experiments or anecdotal observations in wild apes, the habitual and voluntary consumption of ethanol in this evolutionary radiation has been documented until now ...,

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The Origin of Representational Drawing: A Comparison of Human Children and Chimpanzees.
November 06, 2014

To examine the evolutional origin of representational drawing, two experiments directly compared the drawing behavior of human children and chimpanzees. The first experiment observed free drawing after model presentation, using imitation task. From longitudinal observation of humans (N = 32, 11?31 months), the developmental process of drawing until the emergence of shape imitation was clarified...,

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Chimpanzees and Humans Mimic Pupil-Size of Conspecifics.
August 21, 2014

Group-living typically provides benefits to individual group members but also confers costs. To avoid incredulity and betrayal and allow trust and cooperation, individuals must understand the intentions and emotions of their group members. Humans attend to other's eyes and from gaze and pupil-size cues...,

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Chimpanzee choice rates in competitive games match equilibrium game theory predictions.
June 05, 2014

The capacity for strategic thinking about the payoff-relevant actions of conspecifics is not well understood across species. We use game theory to make predictions about choices and temporal dynamics in three abstract competitive situations with chimpanzee participants ...

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How dolphins see the world: A comparison with chimpanzees and humans
January 17, 2014

Bottlenose dolphins use auditory (or echoic) information to recognise their environments, and many studies have described their echolocation perception abilities. However, relatively few systematic studies have examined their visual perception. We tested dolphins on a visual-matching task using two- ...

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Differences between chimpanzees and humans in visual temporal integration
November 21, 2013

Humans have a superior ability to integrate spatially separate visual information into an entire image. In contrast, comparative cognitive studies have demonstrated that nonhuman primates and avian species are superior in processing relatively local features; however...

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A ground-like surface facilitates visual search in chimpanzees (Pan troglodytes).
August 07, 2013

Ground surfaces play an important role in terrestrial species' locomotion and ability to manipulate objects. In humans, ground surfaces have been found to offer significant advantages in distance perception and visual-search tasks...

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Behavioral recovery from tetraparesis in a captive chimpanzee.
2013.05.17

An adult male chimpanzee living in a captive social group at the Primate Research Institute of Kyoto University developed acute tetraparesis. He was paralyzed and received intensive care and veterinary treatment as previously reported in Miyabe-Nishiwaki et al. (J Med Primatol 39:336?346, 2010). The behavioral recovery of the chimpanzee was longitudinally ...

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Head-Mounted Eye Tracking of a Chimpanzee under Naturalistic Conditions
2013.04.10

This study offers a new method for examining the bodily, manual, and eye movements of a chimpanzee at the micro-level. A female chimpanzee wore a lightweight head-mounted eye tracker (60 Hz) on her head while engaging in daily interactions with the human experimenter. The eye tracker recorded her eye movements accurately while the chimpanzee freely moved her head, hands, and body...

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Spontaneous synchronized tapping to an auditory rhythm in a chimpanzee
2013.03.28

... we show the first evidence that a member of our closest living relatives, a chimpanzee, spontaneously synchronizes her movement with an auditory rhythm: After a training to tap illuminated keys on an electric keyboard, one chimpanzee spontaneously aligned her tapping with the sound when she heard an isochronous distractor sound...

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Brain response to affective pictures in the chimpanzee
2013.02.26

Advancement of non-invasive brain imaging techniques has allowed us to examine details of neural activities involved in affective processing in humans; however, ...

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Basis for cumulative cultural evolution in chimpanzees: social learning of a more efficient tool-use technique.
2013.01.31

The evidence for culture in non-human animals has been growing incrementally over the past two decades. However, the ability for cumulative cultural evolution, with ...

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Relative contributions of goal representation and kinematic information to self-monitoring by chimpanzees and humans
2012.08.23

It is important to monitor feedback related to the intended result of an action while executing that action. This monitoring process occurs hierarchically; that is, sensorimotor processing occurs at ...

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Chimpanzee carrying behaviour and the origins of human bipedality.
2012.03.20

Why did our earliest hominin ancestors begin to walk bipedally as their main form of terrestrial travel? The lack of sufficient fossils and differing interpretations of existing ones leave unresolved the ...

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Humans and chimpanzees attend differently to goal-directed actions.
2012.02.21

Humans comprehend the actions of others by making inferences about intentional mental states of another. However, little is known about how this capacity develops and whether this is shared with other animals. Here we show ...

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Chimpanzees' flexible targeted helping based on an understanding of conspecifics' goals
2012.02.07

Humans extensively help others altruistically, which plays an important role in maintaining cooperative societies. Although some nonhuman animals are also capable of helping others altruistically, humans are ...

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Mechanism of birth in chimpanzees: humans are not unique among primates
2011.

Researchers have argued that the process of human birth is unique among primates and mammals in that the infant emerges with its face oriented in the opposite direction from its mother (occiput anterior) and head rotation occurs in the birth canal. However, this notion of human uniqueness has not been substantiated, because there are few comparative studies of birth in non-human primates....

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Chimpanzees' use of conspecific cues in matching-to-sample tasks: public information use in a fully automated testing environment.
2011.

Social animals have much to gain from observing and responding appropriately to the actions of their conspecific group members. This can in turn lead to the learning of...

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Working memory of numerals in chimpanzees.
2007.12.03

Chimpanzee memory has been extensively studied. The general assumption is that, as with many other cognitive functions, it is inferior to that of humans; some data, however, suggest that, in some circumstances, chimpanzee memory may indeed be superior to human m...

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A new notation system of object manipulation in the nesting-cup task for chimpanzees and humans.
2007.

The nesting-cup task has been used to assess cognitive capability in humans as well as non-human primates. Previous studies have attempted to highlight interesting aspects of behavior by constructing and assessing various categories of manipulation. The present study introduces a new notation system for ...

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Chimpanzees share forbidden fruit.
2007.

The sharing of wild plant foods is infrequent in chimpanzees, but in chimpanzee communities that engage in hunting, meat is frequently used as a social tool for nurturing alliances and social bonds. Here we report the only recorded example of regular sharing of plant foods by unrelated, non-provisioned wild chimpanzees ...

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Behavior of infant chimpanzees during the night in the first 4 months of life: smiling and suckling in relation to behavioral state.
2006.

This article reports the behavior of 3 newborn chimpanzees in the first 4 months of life, reared by their mothers and living in a community of 14 chimpanzees in a semi-natural enriched environment. We focused on spontaneous activity during the night partly ...

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Food transfer between chimpanzee mothers and their infants.
2004.

Food sharing among chimpanzees is known to occur particularly between mothers and infants and has been proposed to be a form of parental investment. To explore the function of food sharing, it is essential to know how and what is transferred to an infant from its mother. We investigated details of interactions leading to food transfer and characteristics of items transferred in three mother?infant pairs in captivity...

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Contagious yawning in chimpanzees.
2004.

Six adult female chimpanzees were shown video scenes of chimpanzees repeatedly yawning or of chimpanzees showing open-mouth facial expressions that were not yawns. Two out of the six females showed significantly higher frequencies of yawning ...

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Role of mothers in the acquisition of tool-use behaviours by captive infant chimpanzees.
2003.

This article explores the maternal role in the acquisition of tool-use behaviours by infant chimpanzees (Pan troglodytes). A honey-fishing task, simulating ant/termite fishing found in the wild,...

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Numerical memory span in a chimpanzee
2000.

A female chimpanzee called Ai has learned to use Arabic numerals to represent numbers. She can count from zero to nine items, which she demonstrates by touching the appropriate number on a touch-sensitive monitor, and she can order the numbers from zero to nine in sequence...

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