7,807 research outputs found
Chimpanzee alarm call production meets key criteria for intentionality
No full textDetermining the intentionality of primate communication is critical to understanding the evolution of human language. Although intentional signalling has been claimed for some great ape gestural signals, comparable evidence is currently lacking for their vocal signals. We presented wild chimpanzees with a python model and found that two of three alarm call types exhibited characteristics previously used to argue for intentionality in gestural communication. These alarm calls were: (i) socially directed and given to the arrival of friends, (ii) associated with visual monitoring of the audience and gaze alternations, and (iii) goal directed, as calling only stopped when recipients were safe from the predator. Our results demonstrate that certain vocalisations of our closest living relatives qualify as intentional signals, in a directly comparable way to many great ape gestures. We conclude that our results undermine a central argument of gestural theories of language evolution and instead support a multimodal origin of human language
Experimental field studies with non-human primates
No full textThis project has received funding from the European Union’s Seventh Framework Programme for research, technological development and demonstration under grant agreement no 283871.One way to study language evolution is to compare human communication with closely related non-human primate species. This comparative approach has turned to be especially productive if subjects are studied under natural field conditions in which they have evolved. Various observation techniques have been developed, but field experiments are often needed to clarify underlying cause-effect relations. Here, I review the main experimental designs that are suitable for primate fieldwork and discuss some scientific advancements that they have generated. Field experiments are notoriously difficult to carry out for a range of reasons that are discussed. Nonetheless, considerable progress has been made in recent years, including with great apes, which have traditionally been neglected in experimental research in the wild.Peer reviewe
Chimpanzees Extract Social Information from Agonistic Screams
No full textChimpanzee (Pan troglodytes) agonistic screams are graded vocal signals that are produced in a context-specific manner. Screams given by aggressors and victims can be discriminated based on their acoustic structure but the mechanisms of listener comprehension of these calls are currently unknown. In this study, we show that chimpanzees extract social information from these vocal signals that, combined with their more general social knowledge, enables them to understand the nature of out-of-sight social interactions. In playback experiments, we broadcast congruent and incongruent sequences of agonistic calls and monitored the response of bystanders. Congruent sequences were in accordance with existing social dominance relations; incongruent ones violated them. Subjects looked significantly longer at incongruent sequences, despite them being acoustically less salient (fewer call types from fewer individuals) than congruent ones. We concluded that chimpanzees categorised an apparently simple acoustic signal into victim and aggressor screams and used pragmatics to form inferences about third-party interactions they could not see.Peer reviewe
Chimpanzee lip-smacking facilitates cooperative behaviour
No full textPF was funded by Swiss National Science Foundation and European Research Council project grants (Prilang 283871) to KZ.Signalling plays an important role in facilitating and maintaining affiliative or cooperative interactions in social animals. Social grooming in primates is an example of an interaction that requires coordination between partners but little is known about communicative behaviours facilitating this activity. In this study, we analysed the communication of wild chimpanzees of Budongo Forest, Uganda, as they entered and maintained a naturally occurring cooperative interaction: social grooming. We found that lip-smacking, a distinct multimodal oral gesture produced during grooming, coordinated this activity. Lip-smacking at the beginning of grooming bouts was significantly more often followed by longer and reciprocated bouts than silent grooming initiations. Lip-smacks were more likely to be produced when the risk of termination of the interaction by the recipient was high, for instance when grooming vulnerable body parts. Groomers were also more likely to produce lip-smacks during face-to-face grooming where the visual aspect of the signal could be perceived. Data are consistent with the hypothesis that chimpanzee lip-smacks function to coordinate and prolong social grooming, suggesting that this oral signal is an example of a communicative behaviour facilitating cooperative behaviour in chimpanzees.Peer reviewe
The Design and Implementation of a Key Performance Indicator Dashboard for KE-chain
No full textKE-works is a six years old company which aims to optimise the product development process in industrial applications. To accomplish this, KE-works deploys a web-application called KE-chain. KEchain is an engineering workflow management system with the objective to increase the efficiency of the product development process through better control, more efficient distribution, access and use of product-related information. Users have the possibility to set-up a project, manage the tasks belonging to this project, and control the workflow and information distribution. With KE-chain users are able to create structure in the heap of information that composes their product and, when used right, improve the process of their project development. One of the key elements in optimising the product development process is the monitoring of the available data to give users insight in the status of the project. Currently it is difficult to get a good overview of a project within KE-chain and it is not possible to see what tasks are cirtical at a certain moment. A common way of showing the status or performance of systems is the use of Key Performance Indicators (KPI’s). These indicators, for example in the form of a graph or a table, can quickly give information about the performance of a system. KE-works has decided that it wants to give its users an overview in the formof a project-specific dashboard with KPI widgets. Therefore the assignment is to design and develop an integrated KPI dashboard into KE-chain. To design the KPI dashboard, which we named KE-board, we shortly researched the field of Performance Measurement to get an overview of the different approaches for the design of KPI’s. As a basis for the design we have adopted the Lean methodology [1] which has been used by KE-works in the past. In our research we have actually connected the Lean wastes to measures in KE-chain. To do this, we have chosen a bottom-up approach, which means we started by identifying the available data, after which we extracted several groups of measures. We have interviewed several clients of KEworks, the users of KE-chain. From these interviews we deducted which groups of measures were important for which user roles. To verify which measures are of importance for these dashboards, we have questioned and interviewd the consultants of KE-works. By combining the results of the interviews and the questionnaires we designed 7 KPI widgets. Finally, we created KE-board and integrated it into KE-chain in five weeks of implementation. After that we have evaluated the complete dashboard by interviewing the consultants of KE-works. On top of that, we have sent them a questionnaire in which they rated the functionality of the widgets to see if they contribute to their purpose and achieve the goals that we set for them. KE-board has been received well by the management and employees of KE-works and according to the extensive evaluation we can state that it definitely contributes to the optimization of the product development process in KE-chain.Computer ScienceComputer ScienceElectrical Engineering, Mathematics and Computer Scienc
Linguistic capacity of non-human animals
No full textThis paper was funded by European Union's Seventh Framework Programme for research, technological development and demonstration. Grant Number: 283871Linguists interested in language evolution tend to focus on combinatorial features and rightly point out the lack of comparable evidence in animal communication. However, human language is based on various unique capacities, such as a motor capacity of sophisticated vocal control and a cognitive capacity of acting on others' psychological states. These features are only present in very rudimentary forms in non-human primates, suggesting they have evolved more recently in the human lineage. Here, the evidence from recent fieldwork for precursors of these abilities is reviewed, notably sequence-based semantic communication, vocal tract control, and audience awareness. Overall, there is evidence for both continuity and discontinuity when comparing modern primate and human communication, suggesting that the origin of language is the result of multiple gradual transitions from earlier forms of primate-like communication and social cognition, rather than a sudden and fundamental redesign in ancestral human communication and cognition.Peer reviewe
Chimpanzee pant-hoots encode individual information more reliably than group differences
No full textVocal learning, the ability to modify the acoustic structure of vocalizations based on social experience, is a fundamental feature of speech in humans (Homo sapiens). While vocal learning is common in taxa such as songbirds and whales, the vocal learning capacities of nonhuman primates appear more limited. Intriguingly, evidence for vocal learning has been reported in chimpanzees (Pan troglodytes), for example, in the form of regional variation ("dialects") in the "pant-hoot" calls. This suggests that some capacity for vocal learning may be an ancient feature of the Pan-Homo clade. Nonetheless, reported differences have been subtle, with intercommunity variation representing only a small portion of the total acoustic variation. To gain further insights into the extent of regional variation in chimpanzee vocalizations, we performed an analysis of pant-hoots from chimpanzees in the neighboring Kasekela and Mitumba communities at Gombe National Park, Tanzania, and the geographically distant Kanyawara community at Kibale National Park, Uganda. We did not find any statistically significant differences between the neighboring communities at Gombe or among geographically distant communities. Furthermore, we found differences among individuals in all communities. Hence, the variation in chimpanzee pant-hoots reflected individual differences, rather than group differences. Thus, we did not find evidence of dialects in this population, suggesting that extensive vocal learning emerged only after the lineages of Homo and Pan diverged
Optimal upper bound for the infinity norm of eigenvectors of random matrices
No full textLet be a random Hermitian (or symmetric) matrix whose upper diagonal and diagonal entries are independent random variables with mean zero and variance one. It is well known that the empirical spectral distribution (ESD) converges in probability to the semicircle law supported on . In this thesis we study the local convergence of ESD to the semicircle law. One main result is that if the entries of are bounded, then the semicircle law holds on intervals of scale . As a consequence, we obtain the delocalization result for the eigenvectors, i.e., the upper bound for the infinity norm of unit eigenvectors corresponding to eigenvalues in the bulk of spectrum, is . The bound is the same as the infinity norm of a vector chosen uniformly on the unit sphere in . We also study the local version of Marchenko-Pastur law for random covariance matrices and obtain the optimal upper bound for the infinity norm of singular vectors. This is joint work with V. Vu. In the last chapter, we discuss the delocalization properties for the adjacency matrices of ErdH{o}s-R'{e}nyi random graph. This is part of some earlier results joint with L. Tran and V. Vu.Ph. D.Includes bibliographical referencesIncludes vitaby Ke Wan
Evaluation of public engagement activities to promote science in a zoo environment
No full textScientists are increasing their efforts to promote public engagement with their science, but the efficacy of the methods used is often not scientifically evaluated. Here, we designed, installed and evaluated the educational impact of interactive games on touchscreens at two primate research centres based in zoo environments. The games were designed to promote interest in and understanding of primates and comparative psychology, as a scaffold towards interest in science more generally and with the intention of targeting younger individuals (under 16's). We used systematic observational techniques and questionnaires to assess the impact of the games on zoo visitors. The games facilitated increased interest in psychology and science in zoo visitors, and changed the knowledge of visitors, through demonstration of learning about specific scientific findings nested within the games. The impact of such devices was greatest on younger individuals (under 16's) as they were significantly more likely to engage with the games. On the whole, therefore, this study demonstrates that interactive devices can be successful educational tools, and adds to the growing body of evidence that conducting research on public view in zoos can have a tangible impact on public engagement with science
Development of zein-based ice nucleator films for frozen food applications
No full textThis research aimed at developing zein-based ice nucleation films for the applications of frozen foods. Acetic acid was chosen as the solvent to cast zein films with flawless surface. Tributyl citrate (TBC) was mixed into zein films to various proportions and 10% TBC was most effective on improving mechanical properties resulting in 2.3-fold more flexibility and 5.8-fold more toughness compared to unplasticized zein films. But incorporation of 20% TBC significantly decreased the water absorption by 19% compared to 10% TBC. Thus, zein films with 20% TBC with good flexibility and water resistance was used in following experiments. The activity of ECINs was stable at pH between 4.0 and 9.0 and ionic strength between 0.01 M and 0.10 M. In the development of INFs, the optimum adsorption of ECINs on zein films surface occurred through layer-by-layer method at pH 7.0 and ionic strength of 0.05 M on UV/ozone-treated zein. A novel method was developed to quantify the activity of INFs, which revealed that the highest activity of zein-based INFs reached 175 units/mm2. The zein-based ice nucleation films (INFs) were used to wrap frozen bread dough during five freeze/thaw cycles. The high-activity INF was as effective as blending ECINs in improving the yeast survival by 40%, and consequently increased the specific volume of bread loaf by 25%. Furthermore, high-activity INFs prevented the dehydration of frozen dough and thus significantly reduced the crumb hardness by 36% and increased the crumb springiness by 1.25 times. On energy saving, zein-based INFs were less potential than blended ECINs. INFs only reduced the time of freezing by 6% compared to the 20% by blended ECINs. However, the total amount of ECINs used on wrapping a piece of dough was only about 1/200 of the amount through blending. In addition, ECINs immobilized on the zein films showed desirable stability to sustain at least fifteen repetitive uses on freezing water.Ph. D.Includes bibliographical referencesIncludes vitaby Ke Sh
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