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A Study of Problem Solving By Gibbons
Abstract
Four gibbons were presented with five types of string-pulling problems based on those used by KÖHLER to demonstrate insight. Contrary to the results of previous research on problem-solving ability in gibbons, all of the problems were solved quickly and efficiently. Their success is attributed to the fact that, in the present research, the strings were elevated so as not to be lying on a flat surface. Such a design is more suitable to the anatomy and sensory capacities of these animals and more in accord with the types of manipulable objects which are found in their natural environment. At least one of the problem types was solved insightfully. It is concluded that the sudden appearance of a complete, adaptive (
... Neste sentido, Hebb (1949, p. 164) aponta que se o "Insight" suplementa toda a aprendizagem, não podemos mais falar do fenômeno como um processo a parte e diferente de aprendizagem, mas sim uma de suas propriedades, decorrente de arranjos específicos de contingências que reorganizam e integram experiências passadas. Esta forma de se conceituar o "Insight" está bem próxima do que psicólogos cognitivos hoje chamam de "entendimento de causalidade", que seria um entendimento generalizado de relações entre eventos, o que possibilita a previsão de consequências de determinadas ações (Kummer, 1995) De qualquer forma, o trabalho de Köhler (1925Köhler ( /1948 com chimpanzés foi pioneiro e inovador (Henle, 1985), e suscitou uma série de pesquisas empíricas sobre a capacidade de resolução de problemas em primatas (Bingham, 1929;Pechstein & Brown 1939;Jackson, 1942;Razran, 1961;Beck, 1967;Menzel, Davenport & Rogers, 1970). ...
... O sujeito seguiu o ritual, emitindo respostas anteriormente reforçadas, não demonstrando um repertório inovador e mais econômico. Posteriormente Voronin e Firsov(1967( , citado em Reznikova, 2007 concluíram que o desempenho rígido de Raphael se deu por o sujeito ter aprendido a sequência como um todo, como em um encadeamento, e não de forma independente.Voronin e Firsov(1967( , citado em Reznikova, 2007 replicaram o estudo de Vatsuro (1941, citado em Reznikova, 2007) com uma chimpanzé fêmea, chamada Lada. Ao invés de treinar o animal em uma sequência, os autores optaram por um treino independente, e com um conjunto de ferramentas distintos no treino e no teste. ...
... O sujeito seguiu o ritual, emitindo respostas anteriormente reforçadas, não demonstrando um repertório inovador e mais econômico. Posteriormente Voronin e Firsov(1967( , citado em Reznikova, 2007 concluíram que o desempenho rígido de Raphael se deu por o sujeito ter aprendido a sequência como um todo, como em um encadeamento, e não de forma independente.Voronin e Firsov(1967( , citado em Reznikova, 2007 replicaram o estudo de Vatsuro (1941, citado em Reznikova, 2007) com uma chimpanzé fêmea, chamada Lada. Ao invés de treinar o animal em uma sequência, os autores optaram por um treino independente, e com um conjunto de ferramentas distintos no treino e no teste. ...
Experimental Psychology utilizes problem-solving methodology since its inception. Much was debated about the effects of training variables upon the solution of a problem, especially concerning the sudden solution of specific problem, called Insight. The present work aimed to investigate the solution of different problem in different species after the independent training of pre-requisite repertoires. Additionally, tests regarding the understanding of functional properties of stimuli were made. In Experiment I, two pigeons (Columba livia) were tested in the box-displacement test. The subjects learned to, a) push a box towards a target, and b) to climb and peck another target. The final task required to subjects to push one box towards a target hanging in the ceiling, climb the box and then peck the target. The two subjects solved the final task. In Experiment II, four pigeons had an asymmetric training of the two abilities. Only one of the subjects solved the final task, not as fluidly as the subjects from Experiment I. In Experiment III, the consequence used during the training of each ability was different. Pushing towards a target was reinforced with food, and to climb and peck with water. None of the four birds solved the task in its first presentation. All the subjects that solved the tasks in Experiments I, II and III showed similar performances in the tests regarding the understanding of functional properties of stimuli, suggesting that even minima changes in the test situation can impair the solution. Experiment IV employed a new task, with rats (Rattus norvegicus). Subjects learned to a) digg shavings, and b) climb stairs. In the final task, the rats had to digg and find a passage leading to another ambient containing stairs that lead to food. Two rats that learned the two abilities solved the problem, suddenly. Other four rats that learned only one of the two abilities (dig or climb) didnt solved the problem. Experiment V tested the effects of quantities of training (Experiment II), consequences of trained abilities (Experiment III), and context of training and testing with new caledonian crows (Corvus moneduloides). All four crows solved the problem, but not suddenly. The data of all experiments suggests that the sudden solution, when acquired through the interconnection of repertoires is more subtle then it is usualy regarded, and that variables of training and testing are crucial for the solution of a problem
http://www.teses.usp.br/teses/disponiveis/47/47132/tde-15072015-101008/pt-br.php
... Animals with poor attention are more likely to fail (Warden, Koch, & Fjeld, 1940) or pull unbaited strings without monitoring feedback (Beck, 1967). Divided attention could explain the difficulty of more complex conditions (Heinrich & Bugnyar, 2005;Nissani, 2004). ...
... Inhibition Animals might pull strings at random if they have poor inhibition, which is especially a problem when tested on patterned problems after the single string condition (Seibt & Wickler, 2006). Limb use and laterality Animals often fail if they lack the dexterity to grasp a string or cannot step on it for anchoring (Beck, 1967;Newton, 1967). Limb lateralization seems to be beneficial (Magat & Brown, 2009). ...
... A sometimes overlooked problem is that the pulling action or the string itself may be rewarding. This appears true for several species (e.g., Altevogt, 1954;Beck, 1967;Riesen et al., 1953;Schuck-Paim et al., 2009;Whitt et al., 2009). Sometimes an animal pulls an unbaited string at an equal rate to a baited one, implying that the string pulling is rewarding in itself. ...
String pulling is one of the most widely used paradigms in comparative psychology. First documented 2 millennia ago, it has been a well-established scientific paradigm for a century. More than 160 bird and mammal species have been tested in over 200 studies with countless methodological variations. The paradigm can be used to address a wide variety of issues on animal cognition; for example, what animals understand about contact and connection as well as whether they rely on perceptual feedback, grasp the functionality of strings, generalize across conditions, apply their knowledge flexibly, and possess insight. Mammals are typically tested on a horizontal configuration, birds on a vertical one, making the studies difficult to compare; in particular, pulling a string vertically requires better coordination and attention. A species' performance on the paradigm is often influenced by its ecology, especially concerning whether limbs are used for foraging. Many other factors can be of importance and should be considered. The string-pulling paradigm is easy to administer, vary, and apply to investigate a wide array of cognitive abilities. Although it can be and has been used to compare species, divergent methods and unclear reporting have limited its comparative utility. With increasing research standards, the paradigm is expected to become an even more fundamental tool in comparative psychology. (PsycINFO Database Record
(c) 2015 APA, all rights reserved).
... Uznawano zatem, że gibony nie są zdolne do korzystania z narzędzi. Beck (1967) zauważa, że konstrukcja dłoni gibona przynajmniej utrudnia mu wykonanie zadania, w związku z czym zwierzęciu brakuje motywacji do jego wykonania. Gdy powtórzył eksperyment, umieszczając potrzebne obiekty w pozycji pionowej, gibony wykorzystywały je do przyciągnięcia pożywienia leżącego poza klatką. ...
... Gdy powtórzył eksperyment, umieszczając potrzebne obiekty w pozycji pionowej, gibony wykorzystywały je do przyciągnięcia pożywienia leżącego poza klatką. Mimo że gibony jako jedyne z rodziny Pongidae nie radziły sobie z zadaniami korzystania z narzędzi (Beck, 1967;Harlow, Uehling, Maslow, 1932), naukowcy przez lata byli skłonniejsi przyznawać, że nie są do tego zdolne, niż zastanowić się nad konstrukcją wykonywanych przez siebie eksperymentów. ...
Celem niniejszego artykułu jest zidentyfikowanie przejawów gatunkowizmu w historii badań nad teorią umysłu u zwierząt innych niż ludzie oraz, co ważniejsze, zidentyfikowanie uprzedzeń poznawczych, które przyczyniają się do przyjmowania nieostrożnych i, jak zobaczymy w dalszych rozdziałach, często fałszywych interpretacji badań empirycznych. Wpływ gatunkowizmu widoczny jest także w szeroko rozumianych animal studies. Przejawy szowinizmu gatunkowego obecne są m.in. w rozważaniach dotyczących teorii umysłu. Analiza klasycznych już artykułów Premarcka i Woodruffa (1978) oraz Calla i Tomasello (2011) ujawnia próbę podtrzymania wiary w ludzką wyjątkowość. Utrzymanie tego przekonania wiąże się czasem z konstruowaniem nieostrożnych interpretacji.
... Furthermore, after having learned this task, they required only a few seconds to complete the task. Both findings go along with those of Beck (1967), whose gibbons were also able to solve all presented rope-pulling tasks. Due to the lack of time, however, no control condition (e.g., available rope without food reward) could be included in the present study. ...
... Such a control should be considered for future examinations to further investigate the gibbons' extent of insight. Beck (1967) reported that his gibbons repeatedly pulled the rope even though no food reward was connected to it. This raises doubt that the individuals actually understood the physical properties of the task and may indicate that rope-pulling was merely a conditioned behavior. ...
Cooperative behaviors among individuals of numerous species play a crucial role in social interactions. There is a special interest in investigating the occurrence of cooperation among apes because this knowledge could also shed light on evolutionary processes and help us understand the origin and development of cooperation in humans and primates in general. Gibbons are phylogenetically intermediate between the great apes and monkeys, and therefore represent a unique opportunity for comparisons. The aim of the present study was to discover whether or not white-handed gibbons (Hylobates lar) show cooperative behaviors. In order to test for the respective behaviors, the gibbons were presented with a commonly used experimental cooperative rope-pulling task. The gibbons in this study did not exhibit cooperative behaviors during the problem-solving task. However, prior training procedures could not be fully completed, hence this project constitutes only the onset of exploring cooperative behaviors in gibbons. Additional behavioral observations revealed that the gibbons spent significantly more time "out of arm's reach to everyone", suggesting that they are less often involved in social interactions, than other, more cooperative primates.
... In the wild, gibbons spend much of their time in trees and rarely pick things up off the ground -indeed, their hand shape makes picking things up off the ground difficult. In comparable tasks involving manipulating objects at shoulder level, gibbons were on a par with other apes after all (Beck, 1967). Many of the best examples of experimental work informed by such considerations relate to memory and timing capacities as used in foraging (Healy & Hurly, 2013), navigation (Cartwright & Collett, 1987;J. ...
One of Clayton’s major contributions to our understanding of animal minds has been her work on episodic-like memory. A central reason for the success of this work was its focus on ecological validity: rather than looking for episodic memory for arbitrary stimuli in artificial contexts, focussing on contexts in which episodic memory would serve a biological function such as food caching. This review aims to deepen this insight by surveying the numerous functions that have been proposed for episodic memory, articulating a philosophically grounded framework for understanding what exactly functions are, and drawing on these to make suggestions for future directions in the comparative cognitive psychology of episodic memory. Our review suggests four key insights. First, episodic memory may have more than one function and may have different functions in different species. Second, cross-disciplinary work is key to developing a functional account of episodic memory. Third, there is scope for further theoretical elaboration of proposals relating episodic memory to food caching and, in particular, future-oriented cognition. Finally, learning-related functions suggested by AI (artificial intelligence)-based models are a fruitful avenue for future behavioural research.
... Rumbaugh and McCormack (1967) reported very mixed hylobatid performances in their comparative studies on associative learning and object discrimination. While most hylobatid subjects tested poorly in comparison to other apes (Pan, Gorilla, and Pongo), Rumbaugh and McCormack (1967) also noted that modifications of their testing method (removing the reward from behind a glass viewing window) during their study allowed their gibbon subjects to perform at higher levels of proficiency, serving as an important reminder that not all forms of NHP cognitive evaluation are equally useful across study species (Abordo, 1976;Bates & Byrne, 2015;Beck, 1967;Beran et al., 2016;Tomasello & Call, 1997). ...
Studies of nonhuman primate cognition have traditionally employed subjects from the monkey (Cercopithecoidea) and ape (Hominidae) lineages, with relatively much less examination of the phylogenetically intermediate gibbons (Hylobatidae). To begin to rectify this gap in our understanding of primate cognition, we used a short-term training and testing method to preliminarily evaluate siamang gibbon (Symphalangus syndactylus) performance on a battery of standardized cognitive tasks, using Monkey CANTAB cognition testing software (Lafayette-Campden Neuroscience) and a computer touchscreen apparatus. Five different operant tasks examining distinct perceptual and cognitive functions were used to train and test each subject over a period of five weeks. Over 1900 cognitive testing trials were completed with three subjects. Despite limited training and testing opportunity, all siamangs achieved proficiency scores well above chance (> 65%) in both Concurrent Discrimination and Spatial Working Memory tasks. Over the limited training opportunities available, our subjects did not achieve proficiency in Delayed Match-to-Sample, Paired Associates Learning, or Conditional Visual Discrimination tasks; however, subjects did exhibit (to varying degrees) improved performance in these tasks, suggesting that additional training may lead to higher proficiency and that siamangs demonstrate effective, task-based learning capabilities. We present one of the first successful tests of a hylobatid ape using touchscreen cognitive testing methods and demonstrate that hylobatids can be evaluated using the same methods now commonly employed in tests of other nonhuman primates. Further, our testing regime proved to be behaviorally rewarding for our subjects, suggesting that hylobatids may benefit from advanced forms of interactive cognitive enrichment.
... Spence 1937). That is, until a scientist modified the task to accommodate the gibbons' elongated hand (Beck 1967). When the items were elevated off a flat surface, the gibbons were able to learn how to participate in the task and correctly solve the problem. ...
... Joining tools, however, was a new, never before observed behavior of Sultan. Stemming from these findings, a series of studies was developed to investigate whether animals were actually capable of solving problems in a sudden manner without direct training, and what of the subject history affected this solution (Bingham 1929;Yerkes 1929, Klüver 1933Grether and Maslow 1937;Maier 1937;Pechstein and Brown 1939;Jackson 1942;Birch 1945;Schiller 1952;Razran 1961;Beck 1967;Menzel et al. 1970;Shurcliff et al. 1971;Frank and Frank 1982;Windholz 1984;Guillaume and Meyerson 1987;Heinrich 1995;Pepperberg 2004;von Bayern et al. 2009;Foerder et al. 2011;Nakajima and Sato 2013). ...
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Abstract: The emergence of novel behavior is a multilayered phenomenon that comprehends distinct processes. One such process is known as insightful problem solving. “Insight” can be explained as the spontaneous interconnection of previously acquired behavioral repertoires. The objective of this study was to investigate: (1) whether capuchin monkeys (Sapajus spp.) do show the interconnection of repertoires, and (2) whether different performances of problem solving could be produced by different training histories. Two repertoires were independently trained: (a) joining two pieces of a tool to manufacture a new tool and (b) raking food with one tool. In the test situation, food was out of reach, and two joinable pieces of a tool, different from the ones used in training, were presented. To solve the problem, the monkeys had to join the two pieces and rake the food with the new manufactured tool. In Experiment 1, one monkey received symmetric training (equal number of sessions) of both repertoires and solved the task, but not in an insightful manner. In Experiment 2, six monkeys were divided into two groups: one group received symmetric training, and the second group had asymmetrical training of the repertoires (unequal number of sessions). Subjects from the symmetric group performed as the monkey in Experiment 1; subjects from the other group showed a sudden insightful solution of the problem. The different performances in the same problem situation can be explained in terms of the behavioral history provided to each group of subjects.
... This theory is currently strongly debated, because it would mean that string-pulling tasks could be solved purely by associative learning without any causal understanding (Jacobs and Osvath 2015). However, there is evidence that some mammals will continue pulling slack strings without any initial perceptual feedback, for example dogs and wolves (Frank and Frank 1985), or even continue pulling when the reward moves away, for example gibbons (Beck 1967) or baboons (Bolwig 1963). In Experiments 2b and 2c the arrangement of the longer string created a situation similar to studies with slack strings, where multiple pulls are required before the reward starts to move. ...
String-pulling is a widely used paradigm in animal cognition research to assess what animals understand about the functionality of strings as a means to obtain an out-of-reach reward. This study aimed to systematically investigate what rules Western scrub-jays (Aphelocoma californica) use to solve different patterned string tasks, i.e. tasks in which subjects have to choose between two or more strings of which only one is connected to the reward, or where one is more efficient. Arranging strings in a parallel configuration showed that the jays were generally capable of solving multiple-string tasks and acted in a goal-directed manner. The slanted and crossed configurations revealed a reliance on a “proximity rule”, that is, a tendency to choose the string-end closest to the reward. When confronted with strings of different lengths attached to rewards at different distances the birds chose according to the reward distance, preferring the reward closest to them, and were sensitive to the movement of the reward, but did not consistently prefer the shorter and therefore more efficient string. Generally, the scrub-jays were successful in tasks where the reward was closest to the string-ends they needed to pull or when string length and reward distance correlated, but the birds had problems when the wrong string-end was closest to the reward or when the food items were in close proximity to each other. These results show that scrub-jays had a partial understanding of the physical principles underlying string-pulling but relied on simpler strategies such as the proximity rule to solve the tasks.
... Even Pavlov's students and colleagues tackled the subject (Ladygina-Kots & Dembovskii, 1969;Reznikova, 2007;Windholz, 1984). Most of the work was done with apes in a variety of different tasks (Beck, 1967;Bingham, 1929;Birch, 1945;Jackson, 1942;Menzel, Davenport, & Rogers, 1970;Pechstein & Brown, 1939;Razran, 1961;Schiller, 1952), but other animals such as monkeys (Grether & Maslow, 1937;Shurcliff, Brown, & Stollnitz, 1971), dogs and wolves (Frank & Frank, 1982), ravens (Heinrich, 1995), crows (von Bayern, Heathcote, Rutz, & Kacelnik, 2009) and elephants (Foerder, Galloway, Barthel, Moore III, & Reiss, 2011) were also tested. Experiments were designed not only to see if different species do show the sudden solution of a problem, but also to identify the effects of the learning history on the solution of a specific problem. ...
The spontaneous interconnection of repertoires is what behavior analysis has to offer as an account of the “Insight” phenomena found in animal cognition studies since the beginning of the 20th century. The majority of the data concerning the spontaneous interconnection of repertoires was obtained with pigeons, although there are a few studies with other species such as crows and humans. No study at this date showed the interconnection of repertoires in a common lab subject, the albino rat. The objective of the present study was to see if the interconnection of repertoires occurred after the training of two separated repertoires: (a) digging shavings and (b) climbing stairs. The final task required the rats dig to find a tunnel beneath shavings that gave access to stairs that lead to food. Six rats (Rattus norvegicus) were tested. Rats that received training on both repertoires (n = 2) solved the final problem in less than 3 minutes, showing a topography that fits the description of an insightful solution. Rats that learned just one of the two repertoires (only to dig, n = 2; or only to climb, n = 2) did not solve the task. These four rats were then subjected to a brief training of the repertoire not trained, and after that, they were re-tested. Only one of them solved the problem in the second test, showing a different topography of resolution compared to the two rats that solved the problem in the first test. The data demonstrated that rats showed the spontaneous interconnection of two independently acquired repertoires, when given the right task. It also indicated that more studies involving the parametric relations between quantities and order of training of prerequisite repertoires are necessary, since the mere brief training of one of the lacking abilities to solve a task, after the first test, did not yield the same topography of resolution as when the two repertoires were concomitantly trained
... Common anti-predator behaviors in gibbons include: choosing sleeping trees which reduce the risk of predation [Fan & Jiang, 2008;Phoonjampa et al., 2010;Reichard, 1998;Tenaza & Tilson, 1985], alarm calling and vocal signals that relay information about predators to neighboring conspecifics [Clarke et al., 2006;Tenaza & Tilson, 1977] and the harassment of some predators [Kappeler, 1981;Uhde & Sommer, 2002]. Given that other primates display the ability to evolve behavioral responses to human hunters within a few generations [Bshary, 2001;Croes et al., 2007] and that gibbons exhibit behavioral plasticity and the ability to problem solve [Beck, 1967;Cunningham et al., 2006;Geissmann, 2009], we expect to see a suite of behaviors in Kloss gibbons that have evolved in response to 2000 or more years of predation by humans. ...
Kloss gibbons (Hylobates klossii) are endemic to the Mentawai Islands in Indonesia and have been subject to human predation for more than 2000 years in the absence of any other significant predators. We investigate the behavior of Kloss gibbons that may be attributed to avoiding human predation. We observed Kloss gibbons in the Peleonan forest in the north of Siberut Island, the northernmost of the Mentawai island chain, over 18 months in 2007 and 2008, and collected data on their singing behavior, the number of individuals present during different conditions and their responses to humans. We examine behaviors that may reduce the risk of predation by humans during singing (the most conspicuous gibbon behavior), daily non-singing activities and encounters with humans. The individual risk of being stalked by hunters is reduced by singing in same-sex choruses and the risk of successful capture by hunters during singing is reduced by singing less often during daylight hours and by leaving the location of male pre-dawn singing before full light (reducing the visual signal to hunters). Groups in the Peleonan also fission during non-singing daily activity and rarely engage in play or grooming, enhancing the crypticity of their monochromatic black pelage in the canopy. We also observed a coordinated response to the presence of humans, wherein one adult individual acted as a “decoy” by approaching and distracting human observers, while other group members fled silently in multiple directions. “Decoy” behavior occurred on 31% of 96 encounters with unhabituated Kloss gibbons that detected our presence. “Decoy” individuals may put themselves at risk to increase the survival of related immatures (and adult females with infants) who have a greater risk of predation. We argue that, in combination, these behaviors are an evolved response to a long history of predation by humans. Am. J. Primatol. © 2014 Wiley Periodicals, Inc.
... The captive hyenas approached the experimental apparatus very quickly and then immediately proceeded to investigate and manipulate the apparatus. We saw no indication that any hyena exhibited behavioral indications of insightful problem solving (Beck, 1967;Kohler, 1925;Yerkes, 1927), including "hesitation, pause, or attitude of quiet concentration," the "appearance of a critical point at which the organism suddenly, directly and definitely performs the required act," or "ready repetition of adaptive response after once performed" (Yerkes, 1927 p. 156). Additionally, when we examine the individual learning curves of each successful captive hyena, we see that only two individuals, Scooter and Zawadi, show near mastery of the solution after their initial trial. ...
... An ecological approach to cognition would thus seem to have validity, but sometimes the conditions of the task, rather than the underlying cognitive mechanism(s) being studied, are what correlate to evolutionary history and ecological niche (note, e.g., Beck, 1967;Bolhuis & Macphail, 2001). In those cases, reconfiguration of the task may allow species to show comprehension of the underlying mechanism. ...
Linking specific cognitive abilities of nonhuman species on a laboratory task to their evolutionary history-ecological niche can be a fruitful exercise in comparative psychology. Crucial issues, however, are the choice of task, the specific conditions of the task, and possibly the subjects' understanding or interpretation of the task. Salwiczek et al. (2012) compared cleaner wrasse fish (Labroides dimidaitus) to several nonhuman primate species (capuchins, Sapajus paella; chimpanzees, Pan troglodytes; orangutans, Pongo abelii) on a task purportedly related to the ecological demands of the fish, but not necessarily of the nonhuman primates; fish succeeded whereas almost all of the nonhuman primates that were tested failed. We replicated the two-choice paradigm of the task with three Grey parrots (Psittacus erithacus), whose ecology, evolutionary history, and cortical capacity are arguably more like those of nonhuman primates than fish. Greys succeeded at levels more like fish than all the nonhuman primates, suggesting possible alternative explanations for their success. Fish and nonhuman primate subjects also experienced a reversal of the initial conditions to test for generalization: Greys were similarly tested; they performed more like fish and capuchins (who now succeeded) than the apes (who continued to fail). (PsycINFO Database Record (c) 2014 APA, all rights reserved).
... They have passed tasks that may indicate insight. For example, gibbons solved three different problems involving obtaining a food reward attached to a piece of string (Beck, 1967). The most difficult of these problems involved learning to pull in the end of the string that initially moved food away from the subject. ...
Differences in the psychological capacities of closely related species are likely due to differences in their brains. Here, we review neuroanatomical comparisons between hominids (i.e., great apes and humans) and their closest living relatives, the hylobatids (i.e., small apes). We report the differences in quantitative, as well as qualitative, neural characteristics on the basis of 19 comparative studies that each included representatives of all hominid genera and at least one genus of hylobatid. The current data are patchy, based on a small number of hylobatids and few neuroanatomical features. Yet a systematic interspecies comparison could help reduce the neuroanatomical search space for the neural correlates underlying psychological abilities restricted to hominids. We illustrate the potential power of this approach by discussing the neural features of visual self-recognition.
... The captive hyaenas approached the experimental apparatus quickly and immediately proceeded to investigate and manipulate the apparatus. We saw no behavioural indications that the hyaenas were engaging in insightful problem solving (Köhler 1925; Yerkes 1927; Beck 1967); in other species such indications include 'hesitation, pause, or attitude of quiet concentration', the 'appearance of a critical point at which the organism suddenly, directly and denitely performs the required act', or 'ready repetition of adaptive response after once performed' (Yerkes 1927, page 156). When we examined the individual learning curves of each successful captive hyaena, we found that only two individuals, Scooter and Zawadi, showed near mastery of the solution after their initial trial. ...
Innovative problem solving enables individuals to deal with novel social and ecological challenges. However, our understanding of the importance of innovation for animals in their natural habitat is limited because experimental investigations of innovation have historically focused on captive animals. To determine how captivity affects innovation, and whether captive studies of animal innovation suffer from low external validity, we need experimental investigations of innovation in both wild and captive populations of the same species in diverse taxa. Here we inquired whether wild and captive spotted hyaenas differ in their ability to solve the same novel technical problem, and in the diversity of exploratory behaviours they exhibit when first interacting with the problem. Our results suggest that wild and captive populations show important differences in their innovative problem-solving abilities. Captive hyaenas were significantly more successful at solving the novel problem, and significantly more diverse in their initial exploratory behaviour, than were wild hyaenas. We were able to rule out hypotheses suggesting that these differences result from excess energy or time available to captive animals. We conclude that captive hyaenas were more successful because captive individuals were less neophobic and more exploratory than their wild counterparts. These results have important implications for our interpretation of studies on innovative problem solving in captive animals and aid our attempts to gain a broader understanding of the importance of innovation for animals in their natural habitat. (C) 2012 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
... Manual skill of some kind is required for almost all of the testing procedures, and there is a strong relationship between overall global indices and manual skill (Deaner, unpublished; van Schaik et al., 1999). Nevertheless, in most of the procedures, differences in manual skill per se cannot explain performance differences (but see Beck, 1967). For instance, in object discrimination learning sets, reversal learning, oddity learning, and delayed response paradigms, animals must choose which food well to uncover. ...
Although much recent attention has focused on identifying domain-specific taxonomic differences in cognition, little effort has been directed towards investigating whether domain-general differences also exist. We therefore conducted a meta-analysis of published nonhuman primate cognition studies, testing the prediction that some taxa outperform others across a range of testing situations. First, within each of nine experimental paradigms with interspecific variation, we grouped studies by their procedures and the characteristics of their study subjects. Then, using Bayesian latent variable methods, we tested whether taxonomic differences consistently held within or across paradigms. No genus performed especially well within particular paradigms, but genera differed significantly in overall performance. In addition, there was evidence of variation at higher taxonomic levels; most notably, great apes significantly outperformed other lineages. These results cannot be readily explained by perceptual biases or any other contextual confound and instead suggest that primate taxa differ in some kind of domain-general ability. (PsycINFO Database Record (c) 2012 APA, all rights reserved)
... Although so far little attention has been paid to gibbons, the very few existing studies have in general reported rather limited cognitive abilities (Abordo 1976;Suddendorf and Collier-Baker 2009). However, studies often suffer from the lack of motivation on the part of the gibbons, inappropriate design of the testing apparatus (Beck 1967), or from very small sample sizes. For example, a recent study reporting some evidence for gaze-following in gibbons tested only two pileated gibbons (Horton and Caldwell 2006). ...
We investigated four gibbon species of two different genera (Hylobates pileatus, H. moloch, H. lar, Symphalangus syndactylus) in terms of their looking behavior in response to a human who either looked up or looked at the gibbon. Comparing those two conditions, gibbons as a group looked up more when the human was looking up, but they also performed more looks in other directions and thus generally looked more in this condition. Unlike great apes, gibbons did not respond differently between conditions when only the first look on every trial was considered. Furthermore, they did not perform double looks up to check where the human was looking and also did not habituate to the human's looks up. This suggests that gibbons co-orient with human gaze, but unlike great apes, they do not take the visual perspective of others.
... Indeed, very little published research has addressed gibbon cognition despite its direct relevance to the phylogenetic reconstruction of hominid evolution (e.g., Suddendorf & Collier-Baker, 2009), perhaps in part because gibbons are notorious for their flightiness and apparently short attention-spans (Abordo, 1976;Inoue, Inoue, & Itakura, 2004;Rumbaugh, 1972). A notable exception is a study by Beck (1967), which reported that, like great apes, gibbons were able to solve several of Köhler's (1925) classic string-pulling problems. Significantly, the lesser apes succeeded only after the tasks had been modified to take account of their arboreal habits and associated anatomical adaptations. ...
Using the cups task, in which subjects are presented with limited visual or auditory information that can be used to deduce the location of a hidden reward, Call (2004) found prima facie evidence of inferential reasoning by exclusion in several great ape species. One bonobo (Pan paniscus) and two gorillas (Gorilla gorilla) appeared to make such inferences in both the visual and auditory domains. However, common chimpanzees (Pan troglodytes) were successful only in the visual domain, and Bornean orangutans (Pongo pygmaeus) in neither. The present research built on this paradigm, and Experiment 1 yielded prima facie evidence of inference by exclusion in both domains for two common chimpanzees, and in the visual domain for two Sumatran orangutans (Pongo abelii). Experiments 2 and 3 demonstrated that two specific associative learning explanations could not readily account for these results. Because an important focus of the program of research was to assess the cognitive capacities of lesser apes (family Hylobatidae), we modified Call's original procedures to better suit their attentional and dispositional characteristics. In Experiment 1, testing was also attempted with three gibbon genera (Symphalangus, Nomascus, Hylobates), but none of the subjects completed the standard task. Further testing of three siamangs (Symphalangus syndactylus) and a spider monkey (Ateles geoffroyi) using a faster method yielded prima facie evidence of inferential reasoning by exclusion in the visual domain among the siamangs (Experiment 4).
... Studies of wild gibbons have addressed topics such as vocal communication, social structure, and feeding ecology (e.g., Chivers 1976;Mitani 1988;Oyakawa et al. 2007). There are some developmental studies in captive gibbons (e.g., Matsuzawa 2002, 2007), but there are relatively few behavioral and cognitive studies (e.g., Beck 1967;Cunningham et al. 2006;Horton and Caldwell 2006;Hyatt 1998;Inoue et al. 2004;Myowa-Yamakoshi and Tomonaga 2001;Ujhelyi et al. 2000). Here, we extend the use of the free-choice task as a means of studying the perceptual and cognitive abilities of gibbons. ...
Visual preference was evaluated in a male agile gibbon. The subject was raised by humans immediately after birth, but lived with his biological family from one year of age. Visual preference was assessed using a free-choice task in which five or six photographs of different primate species, including humans, were presented on a touch-sensitive screen. The subject touched one of them. Food rewards were delivered irrespective of the subject's responses. We prepared two types of stimulus sets. With set 1, the subject touched photographs of humans more frequently than those of other species, recalling previous findings in human-reared chimpanzees. With set 2, photographs of nine species of gibbons were presented. Chimpanzees touched photographs of white-handed gibbons more than those of other gibbon species. The gibbon subject initially touched photographs of agile gibbons more than white-handed gibbons, but after one and two years his choice patterns resembled the chimpanzees'. The results suggest that, as in chimpanzees, visual preferences of agile gibbons are not genetically programmed but develop through social experience during infancy.
... The task is based on the assumption that animals that do not understand the function of the strings will fail the task, or will only be able to succeed through repeated exposure allowing associative learning. Rhesus monkeys (Shepherd 1911), chimpanzees (Köhler 1927;Povinelli 2000), baboons (Bolwig 1963), gibbons (Beck 1967), and cotton-top tamarins (Hauser et al. 1999) all succeeded in string-pulling tasks. Many species of birds have also been tested using vertical rather than horizontal strings. ...
This study explored how domestic cats perform in a horizontal string-pulling task to determine whether they understand this case of physical causality. Fifteen cats were tested on their ability to retrieve an unreachable food treat in three different set-ups: (a) a single baited string, (b) two parallel strings where only one was baited and (c) two crossed strings where only one was baited. All cats succeeded at pulling a single string to obtain a treat, but none consistently chose the correct string when two strings were parallel. When tested with two crossed strings one cat chose the wrong string consistently and all others performed at chance level. There was no evidence that cats understand the function of the strings or their physical causality.
... Yet the cognitive capabilities of these species remains open to question. Historically gibbon research has been limited, and our knowledge of this species continues to be restricted to a handful of reports: mirror self recognition behaviour (Ujhelyi et al., 2000; Hyatt, 1998), problem solving (Beck, 1967) and object manipulation (Cunningham et al., in press). In the light of this, our first aim involved the use of newly established research techniques to determine whether a lesser ape species was capable of basic visual co-orientation behaviour. ...
This study investigated attentional processes in a sample of captive gibbons. An initial aim of the research was to examine subjects' ability to co-orient with photographic images of both conspecific and human models. The gibbons' expectancies about the focus of another's attention was then also assessed, with an expectancy violation paradigm revealing subjects' sensitivity to an incompatibility between visual orientation and the position of a target object. The gibbons were exposed to two conditions; consistent sequences in which the stimulus individual directed attention towards a target object, and inconsistent sequences in which the model's attentional focus was incompatible with the location of this article. Analyses of the subjects' responses were made according to the direction of gazes and the time spent inspecting the depicted model in each of these conditions. The results reveal a tendency for visual co-orientation with both conspecific and human models, suggesting that gibbons are competent in detecting the visual orientation of other species as well as their own. Furthermore, the subjects' tendency to look longer and check back to the depicted model in response to violations in the relationship between an agent and object (target appearing in an opposite direction to model's gaze), suggests that they possess some knowledge of how visual gaze direction relates to external stimuli.
Addressing the welfare needs of nonhuman primates in captivity is a significant challenge due to the differences among different species, sexes, ages, dominance groups, and individuals. Interventions that increase species typical behaviors and/or reduce atypical behaviors or stress for one species, group, individual, or context may cause the opposite in others. One area that has recently gained substantial attention is species’ cognitive needs, which are particularly important for highly encephalized species such as nonhuman primates. In addition, behavioral and social needs are critical for species that have extended life spans and live in complex social groups. In this chapter, we summarize the cognitive, behavioral, and social needs of primates, focusing on the ways in which they vary among species. As we cannot cover each of the hundreds of primate species, we focus on issues that are likely to be important for most of us involved in research and captive management and draw examples from taxa commonly held in captivity, including apes, macaques, callitrichids, and capuchin monkeys. In each section, we outline the ecological or evolutionary basis of primates’ needs and discuss behavioral management strategies designed to meet these needs in captive settings. We hope that this summary of the cognitive, behavioral, and social welfare needs of captive nonhuman primates is useful in informing which enrichment strategies will be the most effective for which species and context.
Social primates face conflicts of interest with other partners when their individual and collective interests collide. Despite living in small, primarily bonded, groups compared to other social primates, gibbons are not exempt from these conflicts in their everyday lives. In the current task, we asked whether dyads of gibbons would solve a conflict of interest over food rewards. We presented dyads of gibbons with a situation in which they could decide whether to take an active role and pull a handle to release food rewards at a distance or take a passive role and avoid action. In this situation, the passive partner could take an advantageous position to obtain the rewards over the active partner. Gibbons participated in three conditions: a control condition with no food rewards, a test condition with indirect food rewards and a test condition with direct food rewards. In both test conditions, five rewards were released at a distance from the handle. In addition, the active individual could obtain one extra food reward from the handle in the direct food condition. We found that gibbons acted more often in the two conditions involving food rewards, and waited longer in the indirect compared to the direct food condition, thus suggesting that they understood the task contingencies. Surprisingly, we found that in a majority of dyads, individuals in the active role obtained most of the payoff compared to individuals in the passive role in both food conditions. Furthermore, in some occasions individuals in the active role did not approach the location where the food was released. These results suggest that while gibbons may strategize to maximize benefits in a competitive food task, they often allowed their partners to obtain better rewards. Our results highlight the importance of social tolerance and motivation as drivers promoting cooperation in these species.
Social primates face conflicts of interest with other partners when their individual and collective interests collide. Despite living in small, primarily dyadic, groups compared to other social primates, gibbons are not exempt from these conflicts in their everyday lives. In the current task, we asked whether pairs of gibbons would solve a conflict of interest over food rewards. We presented pairs of gibbons with a situation in which one pair member, the actor, could release food rewards at a distance, giving the passive partner a chance to take an advantageous position to obtain the rewards. Gibbons participated in three conditions: A No Food control, an Altruistic situation in which the actor could not obtain a direct reward from the cooperative act and a Test condition in which the actor could secure a small fraction of the total rewards. We found that gibbons acted more often in the two conditions involving food rewards, and waited longer when no direct rewards were available for the actor, thus suggesting that they understood the mechanism and that they faced a social trade-off between making the rewards available and waiting for each other to act. However, we found that in a majority of pairs, acting individuals benefitted more than the passive partners in both altruistic and test conditions. Furthermore, in some occasions actors actively refused to approach the location where the food was released. These results suggest that while gibbons strategize to solve the social dilemmas, they often allowed their partners to obtain better rewards. Our results highlight the importance of social tolerance and motivation as drivers promoting cooperation in these pair-living species.
The notion that tool-use is unique to humans has long been refuted by the growing number of observations of animals using tools across various contexts. Yet, the mechanisms behind the emergence and sustenance of these tool-use repertoires are still heavily debated. We argue that the current animal behaviour literature is biased towards a social learning approach, in which animal, and in particular primate, tool-use repertoires are thought to require social learning mechanisms (copying variants of social learning are most often invoked). However, concrete evidence for a widespread dependency on social learning is still lacking. On the other hand, a growing body of observational and experimental data demonstrates that various animal species are capable of acquiring the forms of their tool-use behaviours via individual learning, with (non-copying) social learning regulating the frequencies of the behavioural forms within (and, indirectly, between) groups. As a first outline of the extent of the role of individual learning in animal tool-use, a literature review of reports of the spontaneous acquisition of animal tool-use behaviours was carried out across observational and experimental studies. The results of this review suggest that perhaps due to the pervasive focus on social learning in the literature, accounts of the individual learning of tool-use forms by naïve animals may have been largely overlooked, and their importance under-examined.
Humans share the planet with many wonderfully diverse animal species and human-animal interactions are part of our daily lives. An important part of understanding how humans do and should interact with other animals is understanding how humans think about other animals. In this thesis, I argue that how humans think about the minds of other animals is marked by prejudice and that this prejudice fosters epistemological, metaphysical, and ethical problems related to study of, the conception of, and the conclusions we draw about animal minds. I begin by examining conceptions and representations of animals in popular culture and arguing that they exhibit and foster a problematic prejudice, what I call “animal prejudice.” I then examine how this prejudice affects the general study of animal minds and argue that it leads to epistemological problems that interfere with the aims of science. After reviewing the effects of animal prejudice on the study of animal minds generally, I more closely examine the effects of animal prejudice on the scientific study of animal problem solving, learning, tool use, language, emotion, and empathy. In addition to identifying areas where animal prejudice is negatively affecting the study of animal minds, I also offer suggestions for avoiding and mitigating these effects. To conclude, I review the ethical implications of animal prejudice and its effects on the study of animal minds. Together, these chapters offer an important philosophical contribution to the understanding of animal minds and provide a basis for further discussion on how humans should interact with other animals.
Environmental enrichment plays an integral role in the everyday life of a captive non-human animal. The introduction of technology, as a form of enrichment to captive animals, has opened a new method for their improved welfare. Two captive Siamang (Symphalangus syndactylus) were introduced to digital enrichment through tablet computers. Their behaviors were observed during their interactions with the tablet applications to ensure they were active participants in demonstrating their preferences regarding long-term choices. This provided them with their own freedom of choice not only in interacting with the tablets but, also in selecting their enrichment activities. The goal is to increase their observed well-being, provide cognitive stimulation, and install a permanent technology area for them to safely access and use when they choose.
Gibbons and siamangs (Hylobatidae), taxonomically apes, have been largely ignored in cognitive research. However, given their unique phylogenetic position, representing an intermediary divergence between monkeys and great apes, and diversity of extant genera, they are ideally placed to study the evolution of cognitive abilities in the hominoid line. This chapter presents a brief review of what is known about the use of objects as tools in the small apes. It also evaluates their understanding of the physical world through object manipulation and tool-use, predominantly based on studies conducted over the last 6 years on gibbons and siamangs housed at the Gibbon Conservation Center (GCC) in California. In a raking-in task, gibbons evidenced potentially insightful comprehension of object relationships when tool and goal were presented in direct alignment. Once the necessary relationships between tool and goal object were not physically situated in the task layout, gibbons performed poorly. This is unexpected given the taxonomic position of the Hylobatidae and their level of cortical development. However, given their unique socio-ecological adaptations, this may reflect differences in cognitive organisation rather than deficiencies.
Previous research has suggested that hylobatids possess limited ability to grasp objects because of their unique hand shape; however information on the manipulative abilities of gibbon hands is scarce. This study explores the ways gibbons use their hands to transport, manipulate, and hold objects, thus offering insight into the cognitive and functional abilities of the small apes. Our investigation monitored object contact and manipulation technique employed by two pairs of captive adult gibbons through focal animal studies by introducing various inanimate objects to their environments. Our results show that hylobatid hands are not immobile hooks, but rather hylobatids are able to manipulate objects in a variety of ways beyond those suggested in previous descriptions of object manipulation. Hylobatids use their first digit extensively during a variety of activities, most often employing the thumb when transporting small objects during travel (carrying food) and when engaging in fine-tuned motor movements. Their frequent use of the thumb alone to pick, probe, and investigate objects indicates that the thumb is of vital importance to hylobatids and is most often employed as a sensory digit.
This chapter will review the current knowledge about the communication and social cognition
of small apes. It will first demonstrate that the new perspective on hylobatid sociality—characterized by a large degree of social flexibility with single-female/multi-male groups representing a common pattern in addition to pair-living, and frequent interactions between groups—has been largely ignored by research into their communicative and socio-cognitive skills. Thus, communication research still considers hylobatids as pair-living, monogamous species adapted to an arboreal habitat. Based on this traditional notion of the hylobatids’ social system, their communication is expected to be dominated by their loud, stereotyped species-specific songs, which travel far in the dense vegetation and are most likely used to defend their territory. Because of their small groups, hylobatid communication is thought to be limited to few facial and gestural signals, and their socio-cognitive skills are expected to be rather modest in comparison to great apes that live in socially more complex groups. Research into hylobatid communication largely focused on their songs, with increasing evidence for intra- and interindividual variation in their acoustic structure, while little is known about other vocalizations. Research into their gestures and facial expressions found considerable repertoires and flexible usage across different social contexts, similar to what has been described for great apes. However, unlike in great apes, research into the socio-cognitive skills of hylobatids often produced inconsistent or negative results. Together these findings demonstrate an unexpected variability and flexibility in hylobatid communication, while the socio-cognitive skills of small apes seem to less sophisticated than those of great apes. At the same time, this chapter points to several gaps of knowledge, which need to be addressed by studying gestures and facial expressions across different hylobatid species, in their natural environments, and by comparing their intra- and intergroup communication. Only then it will be possible to grasp the complexity of hylobatid communication and to adequately study their socio-cognitive skills.
Gibbons have been historically overlooked in the field of comparative social and physical cognition. This study investigated the cognitive abilities of lesser apes in two object permanence tasks. Five gibbons (two Symphalangus syndactylus and three Hyloblates leucogenys) participated in an object permanence task and a single transposition task. The first experiment consisted of a simple visible displacement object permanence task, in which the experimenter placed a food reward under one of three cups placed on a board while the subject observed. The cups were flipped over the food reward and the subject was then asked to gesture towards the correctly baited cup. The second experiment was similar to the first, only a single transposition condition was added. The food reward was placed under one of three cups placed on the same board while the subject observed. The experimenter then switched the cup containing the food reward with one of the two empty cups. The experimenter did not touch the third cup. Once the cups were moved, the subject was asked to gesture towards the correctly baited cup. All gibbons performed significantly above chance in both tasks. There was some variability across subjects in a learning effect and side bias, however, all demonstrated they were capable of identifying an object once unseen and able to track that object once unseen.
A subadult male of a captive harem of hamadryas baboons learned, by instrumental trial-and-error learning, to use a tool to supply food for the harem. The behavior did not spread through the harem by imitation. The subadult male's rank in the harem's dominance hierarchy did not change as a result of his tool use.
situation. The import'ance of understanding the extent and limitations of children's mastery of the logical connectives is evident for any cognitive theory of development, The recent rrork in psycholinguistics, emphasizing the c,olnplex nature of the granmar and senlantics of the language of children, has provided further impetus for seeking such understanding. It seems clear that the decelopment of a bet'ter theory about children's beha,vior and the changes in that behavior with age requires much more detailed infomlaiion about, their linguistic lmbits and competence than me now have. The present st'udy, which consists of two closely related experiments, is meant to contribute to the accumulation of such systematic information. The data of the experiment,s have been ana,lyzed in terms of several specific regression models to provide a deeper insight into what aspects of comprehension of sentential connect'ives are most difficult. The formal relations between various English idioms expressing conjunction, disjunction, and negation, and t'he set-theoretical operations of intersection, union, and complementation are not deeply explored in this paper, but our assumptions about these connections are obvious and uncontroversial. Deeper investigation of these linguistic and senuntical nlat'tere seems desirable as part of any further extensive study of children's conlprehension of logical connectives.
Members of a captive group of Macaca Tonkeana were given the opportunity to use a metal rod to obtain honey which was out of direct reach. Two adolescent males spontaneously learned to use the rod to reach the honey. Learning by the second male appeared to be facilitated through joint manipulation of the rod with the first male to acquire the behaviour. The mothers of these two males contacted the rod more after their sons had learned to use it for getting honey, but none of the adults or juveniles in the group learned to use the rod. The failure of the other members to acquire the new behaviour can be interpreted in terms of the conservatism of adults and the fact that the two adolescents tended to monopolize working with the rod once they had knowledge of its value.
Gibbons often accompany their morning song bouts by spectacular locomotor displays that may include branch shaking and branch braking. These displays typically occur at the climax of the great-call, the most conspicuous and stereotyped song phrase of the female. Here I report on a captive female white-handed gibbon slamming the sliding door of her wooden sleeping box during the climax of her great-call. This special addition to her display produced a single, loud bang which acoustically accentuated the climax of the female's great-call, made her great-call sound unique, and possibly enhanced the call's effect on potential receivers (presumably female conspecifics). The female's use of a door to modify her duet contributions represents a novel behavioural variant, and one of the few cases of tool use in gibbons or small apes. Furthermore, behavioural innovations like this one may have played a role in the evolution of human music.
A group of pigtailed macaques was given the opportunity to use a rod to reach otherwise unavailable food. Initial solution
by one group member resulted from trial and error but subsequent solutions by others were accelerated by three types of observation
learning: social facilitation, stimulus enhancement, and imitative copying. The greater capacity of macaques for observation
learning may explain the greater incidence of tool behavior and subcultural phenomena among macaques than among other cercopithecines.
This experiment examined the performance of common marmosets (Callithrix jacchus) on a series of patterned string problems to assess the marmosets' understanding of means-ends relationships. One marmoset, Jet, was exposed to a series of problems that were ordered in terms of perceived difficulty during two testings that were separated by 1 year. In the second testing, Jet received problems that had been used during the first testing along with three new problems. Each of the new problems was designed to be an exemplar of the type of problem that Jet had experienced difficulty with in the first testing. A second marmoset, Peaches, was tested on the same set of problems given to Jet in the second testing. Results indicated that the marmosets' performance on these problems fell into three categories. In one category, some problems were solved without evidence of trial-and-error learning. In a second category, there were problems in which the marmosets responded at chance levels initially but evidenced improvement as a function of extended testing. In a third category, some problems appeared to be virtually unsolvable even with extended testing. Taken together, these results indicate that the marmosets were able to learn the means-ends connection between pulling a string and obtaining food. This learning was best characterized as a trial-and-error process for some problem forms, while for others there appeared to be rapid learning that did not require extensive practice. The instances of rapid learning may be the result of the application of a simple spatial proximity rule in which the marmosets chose the string that was closest to an imaginary line drawn between the marmoset and the reinforcer.
Gibbons (family Hylobatidae) have rarely been studied in terms of object manipulation and tool use. We assessed whether hoolock gibbons can learn to pull on a rake-like object to gain a food reward, in a zero-order manipulation task, without specific training. Their learning style was assessed along with their understanding of the tertiary relationships between the rake, a goal object and an environmental feature. Hoolocks used a rake to pull in an out-of-reach food item in less than 90 s on first presentation. The gibbons' behaviour suggests that perceptually restructuring the environment may be within this species' abilities. Their causal understanding of three factors, the rake, the reward and a trap into which the reward could fall and be lost, was moderately better than that of chimpanzees, Pan troglodytes, and capuchins, Cebus spp., on a similar task. Learning of simple associative rules, rather than understanding the physical properties of the trap, might explain the gibbons' performance.
Understanding the functionally relevant properties of objects is likely facilitated by learning with a critical role for past experience. However, current evidence is conflicting regarding the effect of prior object exposure on acquisition of object manipulation skills. This may be due to the influence of life history variables on the capacity to benefit from such experience. This study assessed effect of task-relevant object exposure on object-mediated problem-solving in 22 gibbons using a raking-in task. Despite not using tools habitually, 14 gibbons spontaneously used a rake to obtain a reward. Having prior experience with the rake in an unrewarded context did not improve learning efficiency in males. However, females benefitted significantly from the opportunity to interact with the rake before testing, with reduced latencies to solution compared to those with no previous exposure. These results reflect potential sex differences in approach to novelty that moderate the possible benefits of prior experience. Due to their relatively high energetic requirements, reproductively active females may be highly motivated to explore potential resources; however, increased investment in developing offspring could make them more guarded in their investigations. Previous exposure that allows females to learn of an object's neutrality can offset this cautious exploration.
Thesis (M.A.)--University of Sakatchewan, 1978. Includes bibliographical references (p. 212-215).
Ten gibbons of various species (Symphalangus syndactylus, Hylobates lar, Nomascus gabriellae, and Nomascus leucogenys) were tested on object permanence tasks. Three identical wooden boxes, presented in a linear line, were used to hide pieces of food. The authors conducted single visible, single invisible, double invisible, and control displacements, in both random and nonrandom order. During invisible displacements, the experimenter hid the object in her hand before putting it into a box. The performance of gibbons was better than expected by chance in all the tests, except for the randomly ordered double displacement. However, individual analysis of performance showed great variability across subjects, and only 1 gibbon is assumed to have solved single visible and single invisible displacements without recourse to a strategy that the control test eliminated.
Studies to date have indicated few differences in sensory perception among hominoids. Sensory relay nuclei in the dorsal thalamus--portions of the medial and lateral geniculate bodies (MGBp, LGBd) and the ventrobasal complex (VB)--in two gibbons, one gorilla, one chimpanzee and three humans were examined for anatomical similarity by measuring and estimating the nuclear volumes, neuronal densities, numbers of neurons per nucleus, and volumes of neuronal perikarya. The absolute volumes of these nuclei were larger in the larger brains; however, with the volume of the dorsal thalamus as a standard, these sensory relay nuclei showed negative allometry. The gibbons had about half as many neurons as did the other hominoids. Although the human VB had slightly more neurons, the numbers of neurons in LGBd and MGBp did not significantly differ between the great apes and humans. The volumetric distribution of the neuronal perikarya were similar among these hominoids. Other thalamic nuclei had much more diverse numbers of neurons and relative frequencies of their neuronal perikarya. The sensory relay nuclei appear to be a group of conservative nuclei in the forebrain. These results suggest that as a neurological base for complex behaviors evolved in hominids, not all parts of the brain changed equally.
A subadult male from a captive group of Guinea baboons learned, by trial-and-error, to use a tool to rake in food. He then used the tool 104 times over 26 days, thereby providing the group with most of its food. No other group member used the tool during this period. The tool user was removed, and the remainder of the group was given access to the display. None imitated his tool use. It took longer for another finally to learn to use the tool than it had for the initial solution. However, compared with the period before initial solution, group members manipulated the tool more frequently and touched the food pan with the tool nearly twice as many times after the tool user's separation.
This type of tool use appears to be too complex for baboons to imitate directly. However, as a result of observing successful tool use, they attend more to the problem and manipulate the tool more frequently and more accurately. This increase in frequency and accuracy may, in turn, accelerate acquisition of the response by observers through instrumental trial-and-error learning.
The hands of the Hominoidea evidence four adaptive modes which distinguish the lesse apes (Hylobatidae), the orangutan (Pongo), the African apes (Pan), and man (Homo) from one another. The hands of the apes consist of compromises between manipulatory and locomotor functions because selection has operated for precision of grip as well as for special locomotor mechanisms. The human hand is almost totally devoted to manipulation. The hands of gibbons, orangutans and the African apes differ in many features that may be correlated with locomotion. The gibbons and siamang are specially adapted for ricochetal arm-swinging. The great apes possess morphological adaptations for arboreal foraging and climbing distinct from those of the hylobatids. In addition, the African apes have become secondarily adapted for terrestrial quadrupedal locomotion. Many features that distinguish the hands of chimpanzees and gorillas may be associated with the development of efficient knuckele-walking propulsive and support mechanisms.
A bonded pair of hamadryas baboons developed cooperative tool use without training. The male could get food with the tool but first had to get the tool from an adjoining cage which he could not enter. The female learned to give him the tool. Cooperation was temporarily disrupted by the terminal phase of the female's estrous inflation.
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