Comprehension of cause€ffect relations in a tool-using task by chimpanzees (Pan troglodytes).

Five chimpanzees (Pan troglodytes) were tested to assess their understanding of causality in a tool task. The task consisted of a transparent tube with a trap-hole drilled in its middle. A reward was randomly placed on either side of the hole. Depending on which side the chimpanzee inserted the stick into, the candy was either pushed out of the tube or into the trap. In Experiment 1, the success rate of 2 chimpanzees rose highly above chance, but that of the other subjects did not. Results show that the 2 successful chimpanzees selected the correct side for insertion beforehand. Experiment 2 ruled out the possibility that their success was due to a distance-based associative rule, and the results favor an alternative hypothesis that relates success to an understanding of the causal relation between the tool-using action and its outcome. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Task constraints mask great apes' ability to solve the trap-table task.

Researchers have investigated animals' causal knowledge with a task requiring subjects to use a tool to bring a reward within reach whilst avoiding a trap. Previous studies have suggested limitations in the ability of several species to avoid traps in tubes or tables. However, certain features may have inflated task difficulty. We tested 20 chimpanzees (Pan troglodytes), 7 orangutans (Pongo pygmaeus), 5 bonobos (Pan paniscus), and 5 gorillas (Gorilla gorilla) in the trap-table--a task in which subjects have to pull one of two rakes prepositioned behind two rewards on a flat surface. One of the rewards is in front of a trap into which it will fall. We investigated the effect of trap type, tool type, the number of available tools, and reinforcement regime on performance. We replicated previous findings showing that apes failed to choose the correct rake above chance. However, when they could instead choose where to insert a single tool, around 80% of the apes solved the trap-table task in the first trial, revealing an important effect of task constraints on their performance. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Imitation of intentional manipulatory actions in chimpanzees (Pan troglodytes).

In this study, the authors investigated the understanding of other's actions in 5 adult chimpanzees (Pan troglodytes). A human demonstrated an attempt to open different containers. Each container required a different motor pattern to open it. Along with the container, a 2nd object was made available. After a free play period in which the chimpanzees' natural behaviors toward the objects were recorded, the authors tested the following 2 phases: The demonstrator (a) tried but failed to open and (b) opened the container successfully, with 1 of 2 alternative strategies, either using an "irrelevant tool" or by hand. The chimpanzees did not reproduce the demonstrator's motor patterns precisely but did reproduce the demonstrated strategies in both phases. These results suggest that chimpanzees anticipate the intentions of others by perceiving the directionality and causality of object(s) as available cues. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Classifying chimpanzee facial expressions using muscle action.

The Chimpanzee Facial Action Coding System (ChimpFACS) is an objective, standardized observational tool for measuring facial movement in chimpanzees based on the well-known human Facial Action Coding System (FACS; P. Ekman & W. V. Friesen, 1978). This tool enables direct structural comparisons of facial expressions between humans and chimpanzees in terms of their common underlying musculature. Here the authors provide data on the first application of the ChimpFACS to validate existing categories of chimpanzee facial expressions using discriminant functions analyses. The ChimpFACS validated most existing expression categories (6 of 9) and, where the predicted group memberships were poor, the authors discuss potential problems with ChimpFACS and/or existing categorizations. The authors also report the prototypical movement configurations associated with these 6 expression categories. For all expressions, unique combinations of muscle movements were identified, and these are illustrated as peak intensity prototypical expression configurations. Finally, the authors suggest a potential homology between these prototypical chimpanzee expressions and human expressions based on structural similarities. These results contribute to our understanding of the evolution of emotional communication by suggesting several structural homologies between the facial expressions of chimpanzees and humans and facilitating future research. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Absence of knowledge attribution and self-recognition in young chimpanzees (Pan troglodytes).

Mirror self-recognition in chimpanzees is typically delayed until 4.5–8 yrs of age. Also, species capable of mirror self-recognition may be capable of some forms of mental state attribution related to intentions and knowledge. Previous investigations of knowledge attribution by chimpanzees used adolescents and adults but did not explicitly test for self-recognition. The authors report an investigation of knowledge attribution in 6 young chimpanzees previously tested for self-recognition. Ss were required to discriminate between a person who had seen where food was hidden and another person who had not. Results are consistent with the proposition that most chimpanzees younger than 4.5 yrs show neither mirror self-recognition nor knowledge attribution. The results are also consistent with the idea that, just as in humans, development of self-recognition in chimpanzees may precede development of knowledge attribution. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Do chimpanzees (Pan troglodytes) spontaneously take turns in a reciprocal cooperation task?

Reciprocity is considered to be an explanation for altruism toward nonkin. Although there have been many theoretical studies and reciprocity is arguably prevalent in humans, little experimental work has investigated the proximate mechanism of reciprocity in nonhuman animals. The authors tested whether pairs of chimpanzees (Pan troglodytes) would achieve reciprocal cooperation, that is, whether chimpanzees take turns playing donor and recipient roles in an other-rewarding token insertion task. In this task, when a chimpanzee inserts a token into a vending machine, a food reward is delivered to another chimpanzee in an adjacent booth. For 3 pairs of chimpanzees, token insertion persisted in an alternate condition, in which the participants necessarily had to insert tokens alternately, but not in a free condition, in which they freely took turns inserting tokens. In the free condition, one of the chimpanzees was observed to perform a possible solicitation toward the partner who had previously inserted fewer tokens. These findings suggest that there is some difficulty in the occurrence of reciprocal cooperation in chimpanzees. Chimpanzees, differently from humans, might play a donor’s role only on the partner’s request, but not spontaneously. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Trading behavior between conspecifics in chimpanzees, Pan troglodytes.

Bartering of commodities between individuals is a hallmark of human behavior that is not commonly seen in other species. This is difficult to explain because barter is mutually beneficial and appears to be within the cognitive capabilities of many species. It may be that other species do not recognize the gains of trade, or that they do not experience conditions (e.g., low risk) in which barter is most beneficial. To answer these questions, the authors instituted a systematic study of chimpanzees’ ability to barter with each other when doing so materially benefited them. Using tokens derived from symbols they had used since infancy, pairs of adult chimpanzees (Pan troglodytes) could trade between themselves to obtain tokens needed to get foods. Chimpanzees flexibly used the tokens to obtain foods from an experimenter; however, they did not spontaneously trade with their partner. After extensive training, chimpanzees engaged in accurate trade behavior as long as an experimenter enforced the structure of the interaction; however, trade between partners disappeared when this enforcement was removed. The authors discuss possible reasons for these findings as well as implications for the evolution of barter across the primate lineage. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Handedness for tool use correlates with cerebellar asymmetries in chimpanzees (Pan troglodytes).

Recent studies have shown that great ape species possess patterns of macrostructural neocortical asymmetries that are similar to those found in humans. However, little is known about the asymmetry of subcortical structures in great apes. To address this lack of data, the authors assessed left-right asymmetry of the anterior and posterior aspects of cerebellum from MRI brain scans of 53 chimpanzees (Pan troglodytes). No population-level bias was found for either the anterior or the posterior region of the cerebellum. However, a significant inverse association was found in the asymmetry quotients of the anterior and posterior regions, indicating that the cerebellum was torqued at the individual level. Additionally, handedness for tool use but not other measures was associated with variation in cerebellar asymmetries. Last, older chimpanzees had a smaller cerebellum after brain volume was adjusted for. The results are discussed in the context of brain changes in primate evolution related to tool use. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Lack of comprehension of cause€ffect relations in tool-using capuchin monkeys (Cebus apella).

Four tufted capuchin monkeys, successful in a tool task in which they used a stick to push a reward out of a tube, were tested in a similar task, with a tube with a hole and a small trap. Depending on where the stick was inserted, the reward was pushed either out of the tube or into the trap. With the trap-tube task, the authors assessed whether the monkeys understood the cause–effect relation between their behavior and the outcome. In Exp 1, each S underwent 14 10-trial blocks with the trap tube. Three Ss performed at chance level. The 4th S's (Rb) performance improved, reaching 95% success in the last 6 blocks. In Exp 2, Rb received additional tests to investigate its successful strategy further. Rb solved the trap-tube task by means of a distance-based, associative rule. The performances of the 4 Ss indicate that they did not take into account the effects of their actions on the reward. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

How the great apes (Pan troglodytes, Pongo pygmaeus, Pan paniscus, and Gorilla gorilla) perform on the reversed contingency task: The effects of food quantity and food visibility.

S. T. Boysen and G. G. Berntson (1995) found that chimpanzees performed poorly on a reversed contingency task in which they had to point to the smaller of 2 food quantities to acquire the larger quantity. The authors compared the performance of 4 great ape species (Pan troglodytes, Pongo pygmaeus, Pan paniscus, and Gorilla gorilla) on the reversed contingency task while manipulating food quantity (0-4 or 1-4) and food visibility (visible pairs or covered pairs). Results showed no systematic species differences but large individual differences. Some individuals of each species were able to solve the reversed contingency task. Both quantity and visibility of the food items had a significant effect on performance. Subjects performed better when the disparity between quantities was smaller and the quantities were not directly visible. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Experience with the McCoy laryngoscope in difficult laryngoscopy

We report our experience with the McCoy levering laryngoscope in 48 patients who were a Cormack and Lehane grade 3 or grade 4 view at direct laryngoscopy. The view with the blade in neutral position was grade 3 in 39 patients and grade 4 in nine patients. Elevation of the levered tip of the blade in the grade 3 group improved the view to grade 2 in 17 patients (44%), in 17 patients (44%) the view remained unchanged and in five patients (12%) the view deteriorated to grade 4. In the patients initially grade 4, the view improved to grade 3 in one patient and remained unchanged in eight patients. The McCoy laryngoscope is a useful tool to aid intubation in about half of patients who are a grade 3 view at laryngoscopy. Our experience indicates it is unlikely to improve a grade 4 view.     

Processes of social learning in the tool use of chimpanzees (Pan troglodytes) and human children (Homo sapiens).

Common chimpanzees (Pan troglodytes) and 2-yr-old human children (Homo sapiens) were presented with a rakelike tool and a desirable but out-of-reach object. One group of Ss observed a human demonstrator use the tool in one way, and another group observed a demonstrator use the tool in another way. Children in both cases did what the model did. Chimpanzee Ss, however, behaved identically in the 2 model conditions. Both groups performed better than Ss who saw no demonstration. This pattern of results suggests that the chimpanzees were paying attention to the general functional relations in the task and to the results obtained by the demonstrator but not to the actual methods of tool use demonstrated. Human children were focused on the demonstrator's actual methods of tool use (i.e., her behavior). The different social learning processes used by the 2 species have implications for their different forms of social organization. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

合理使用钟罩退火炉退火线材合金材料

本文依据实际经验力求解决长期以来对钟罩炉内部温度的认识误区并根据实际合理使用钟罩炉,提高退火质量。     

Information integration about object–object relationships by chimpanzees (Pan troglodytes).

Three experiments tested the ability to integrate information about object–object relationships in 2 chimpanzees. In Experiment 1, the subjects were trained to match 1 part of a 2-part object to its other part, match a tool to its assembled object, match a container to its tool, and match a tool to its container. In Experiment 2, the subjects were trained to match a picture of the sample. One subject learned this type of matching task and was then tested on whether she could choose the pictures of related items in Experiment 1. Although the subject was reinforced irrespective of her choices, she chose pictures of items related to the sample when there was no picture of the sample. Experiment 3 showed that the subject was able to match a picture of the item among related items. The results suggest that the subject might integrate information about relationships acquired in Experiment 1 and organize it to make networks of related items. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Scale-model comprehension by chimpanzees (Pan troglodytes).

The ability of chimpanzees (Pan troglodytes) to recognize the correspondence between a scale model and its real-world referent was examined. In Experiments 1 and 2, an adult female and a young adult male watched as an experimenter hid a miniature model food in 1 of 4 sites in a scale model. Then, the chimpanzees were given the opportunity to find the real food item that had been hidden in the analogous location in the real room. The female performed significantly above chance, whereas the male performed at chance level. Experiments 3 and 4 tested 5 adult and 2 adolescent chimpanzees in a similar paradigm, using a scale model of the chimpanzees' outdoor area. Results indicate that some adult chimpanzees were able to reliably demonstrate an understanding of the relationship between a scale model and the larger space it represented, whereas other subjects were constrained by inefficient and unsuccessful search patterns. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Language-naive chimpanzees (Pan troglodytes) judge relations between relations in a conceptual matching-to-sample task.

Three chimpanzees with a history of conditional and numeric token training spontaneously matched relations between relations under conditions of nondifferential reinforcement. Heretofore, this conceptual ability was demonstrated only in language-trained chimpanzees. The performance levels of the language-naive animals in this study, however, were equivalent to those of a 4th animal—Sarah—whose history included language training and analogical problem solving. There was no evidence that associative factors mediated successful performance in any of the animals. Prior claims of a profound disparity between language-trained and language-naive chimpanzees apparently can be attributed to prior experience with arbitrary tokens consistently associated with abstract relations and not language per se. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

How Prosimian Primates Represent Tools: Experiments With Two Lemur Species (Eulemur fulvus and Lemur catta).

The authors examined how 2 lemur species (Eulemur fulvus and Lemur catta) reason about tools. Experiment 1 allowed subjects to use 1 of 2 canes to retrieve an inaccessible food reward. Lemurs learned to solve this problem as quickly as other primates. Experiment 2 then presented subjects with novel tools differing from the originals along one featural dimension. Subjects attended more to tools' sizes than to their colors and made no distinction between tools' shapes and textures. Experiments 3 and 4 presented problems in which some of the tools' orientations had to be modified relative to the food. Subjects performed well on these problems, sometimes modifying the position of the tool. These results are discussed in light of the performance of other primates on this task. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Naive chimpanzees' (Pan troglodytes) observation of experienced conspecifics in a tool-using task.

The authors investigated the occurrence of naive chimpanzees' (Pan troglodytes) spontaneous observation of experienced conspecifics during a tool-use task entailing honey fishing. The chimpanzees were presented with 20 kinds of "tools" of which 12 kinds were usable. Six pairs of naive and experienced chimpanzees were brought to this honey-fishing situation. A total of 40 observation episodes occurred between the naive and experienced groups, 34 of which were from naive toward experienced individuals. Naive chimpanzees never observed their partners after their own success but did so after their own failure or before their first attempts. In addition, there were 10 cases in which naive individuals used the left-over tools of the experienced ones. Two factors for the transmission of tool use were clearly evident in this study: (a) spontaneous observation of an appropriate behavioral sequence and (b) enhanced environmental cues made by skilled individuals. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Sex and handedness effects on corpus callosum morphology in chimpanzees (Pan troglodytes).

Findings suggest that in humans, sex and hand preference may be associated with the size of the corpus callosum (CC). The authors measured CC morphology from MRIs in 67 chimpanzees (Pan troglodytes) to see whether similar effects were present in this species. Hand preference was assessed by performance on 4 tasks, and chimpanzees were classified as left-handed, right-handed, or ambidextrous. In a subsequent analysis, the chimpanzees were reclassified into 2 groups: right-handed and left-handed. The results revealed no sex difference in CC area, but significant effects of hand preference were found for several CC regions (rostrum body, anterior midbody, posterior midbody, isthmus, and splenium) and for overall CC size, with left-handed chimpanzees exhibiting significantly smaller CC measurements than right-handed chimpanzees. The results indicate that lateralized hand use in chimpanzees, as in humans, is associated with variation in CC size. (PsycINFO Database Record (c) 2010 APA, all rights reserved)