150 research outputs found
The role of past interactions in great apesâ communication about absent entities
M. Bohn was supported by a scholarship of the German National Academic Foundation. J. Call was supported by the âSOMICSâ ERC-Synergy grant (nr. 609819).Recent evidence suggests that great apes can use the former location of an entity to communicate about it. In this study we built on these findings to investigate the social cognitive foundations of great apesâ communicative abilities. We tested whether great apes (n = 35) would adjust their requests for absent entities to previous interactions they had with their interlocutor. We manipulated the apesâ experience with respect to the interlocutorâs knowledge about the previous content of the now empty location, as well as their experience with the interlocutorâs competence to provide additional food items. We found that apes adjusted their requests to both of these aspects but failed to integrate them with one another. These results demonstrate a surprising amount of flexibility in great apesâ communicative abilities while at the same time suggesting some important limitations in their social communicative skills.PostprintPeer reviewe
Context-sensitive adjustment of pointing in great apes
This research was supported by the European Research Council (ERC) under the European Unionâs Seventh Framework Programme (FP7/2007â2013)/ERC Grant 609819 (SOMICS). Manuel Bohn was supported by the European Unionâs Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 749229.Great apes are able to request objects from humans by pointing. It is unclear, however, whether this is an associated response to a certain set of cues (e.g. the presence and attention of a human addressee) or a communicative signal which can be adjusted to relevant aspects of the spatial and social context. In three experiments, we tested captive great apesâ flexible use of pointing gestures. We manipulated the communicative context so that the default pointing response of apes would have indicated an undesired object, either due to 1) the spatial arrangements of the target objects, 2) the perspective of the addressee or 3) the knowledge of the addressee about the target objectsâ location. The results of the three experiments indicate that great apes can successfully adjust their pointing to the spatial configuration of the referent environment such as distance and location of food. However, we found no evidence that they take the perspective or the knowledge of the addressee into account when doing so. This implies that pointing in great apes is a context-sensitive, but maybe less versatile, communicative signal compared to human pointing.Publisher PDFPeer reviewe
Cooperative problem solving in giant otters (Pteronura brasiliensis) and Asian small-clawed otters (Aonyx cinerea)
Open access funding provided by Max Planck Society.Cooperative problem solving has gained a lot of attention over the past two decades but the range of species studied is still small. This limits the possibility of understanding the evolution of the socio-cognitive underpinnings of cooperation. Lutrinae show significant variations in socio-ecology but their cognitive abilities are not well studied. In the first experimental study of otter social cognition, we presented two species - giant otters and Asian small-clawed otters - with a cooperative problem-solving task. The loose string task requires two individuals to simultaneously pull on either end of a rope in order to access food. This task has been used with a larger number of species (for the most part primates and birds) and thus allows for wider cross species comparison. We found no differences in performance between species. Both giant otters and Asian small-clawed otters were able to solve the task successfully when the coordination requirements were minimal. However, when the temporal coordination demands were increased, performance decreased either due to a lack of understanding of the role of a partner or due to difficulty inhibiting action. In conclusion, two species of otters show some ability to cooperate, quite similar to most other species presented with the same task. However, to draw further conclusions and more nuanced comparisons between the two otter species further studies with varied methodologies will be necessary.Publisher PDFPeer reviewe
Information seeking about tool properties in great apes
M.B. was supported by a scholarship of the German National Academic Foundation. J.C. was supported by the âSOMICSâ ERC Synergy grant (nr. 609819).Evidence suggests that great apes engage in metacognitive information seeking for food items. To support the claim that a domain-general cognitive process underlies ape metacognition one needs to show that selective information seeking extends to non-food items. In this study, chimpanzees (Pan troglodytes) and orangutans (Pongo abelii) either had to determine the location of a desired food item or a property of a non-food item (length of a tool). We manipulated whether subjects received prior information about the itemâs location or property. During the test, subjects had the opportunity to seek the respective information. Results show that apes engaged in more information seeking when they had no prior knowledge. Importantly, this selective pattern of information seeking applied to food as well as to tools.Publisher PDFPeer reviewe
Learning novel skills from iconic gestures : a developmental and evolutionary perspective
This research was supported by Horizon 2020 European Research Council Grant Nos. 609819 and 749229.Cumulative cultural learning has been argued to rely on high fidelity copying of othersâ actions. Iconic gestures of actions have no physical effect on objects in the world but merely represent actions that would have an effect. Learning from iconic gestures thus requires paying close attention to the teacherâs precise bodily movements â a prerequisite for high fidelity copying. Three studies investigated whether 2- and 3-year-old children (N=122) and great apes (N=36) learn novel skills from iconic gestures. When faced with a novel apparatus, participants either watched an experimenter perform an iconic gesture depicting the action necessary to open the apparatus or a gesture depicting a different action. Children, but not great apes, profited from iconic gestures, with older children doing so to a larger extent. These results suggest that high fidelity copying abilities are firmly in place in humans by at least three years of age.PostprintPeer reviewe
Magneto-electrostatic trapping of ground state OH molecules
We report the magnetic confinement of neutral, ground state hydroxyl radicals
(OH) at a density of cm and temperature of 30
mK. An adjustable electric field of sufficient magnitude to polarize the OH is
superimposed on the trap in either a quadrupole or homogenous field geometry.
The OH is confined by an overall potential established via molecular state
mixing induced by the combined electric and magnetic fields acting on the
molecule's electric dipole and magnetic dipole moments, respectively. An
effective molecular Hamiltonian including Stark and Zeeman terms has been
constructed to describe single molecule dynamics inside the trap. Monte Carlo
simulation using this Hamiltonian accurately models the observed trap dynamics
in various trap configurations. Confinement of cold polar molecules in a
magnetic trap, leaving large, adjustable electric fields for control, is an
important step towards the study of low energy dipole-dipole collisions.Comment: 4 pages, 4 figure
Uniting against a common enemy: Perceived outgroup threat elicits ingroup cohesion in chimpanzees
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±éČćăźćŻèœæ§--. äșŹéœć€§ćŠăăŹăčăȘăȘăŒăč. 2021-02-25.Outgroup threat has been identified as an important driver of ingroup cohesion in humans, but the evolutionary origin of such a relationship is unclear. Chimpanzees (Pan troglodytes) in the wild are notably aggressive towards outgroup members but coordinate complex behaviors with many individuals in group hunting and border patrols. One hypothesis claims that these behaviors evolve alongside one another, where outgroup threat selects for ingroup cohesion and group coordination. To test this hypothesis, 5 groups of chimpanzees (N = 29 individuals) were observed after hearing either pant-hoots of unfamiliar wild chimpanzees or control crow vocalizations both in their typical daily environment and in a context of induced feeding competition. We observed a behavioral pattern that was consistent both with increased stress and vigilance (self-directed behaviors increased, play decreased, rest decreased) and increased ingroup cohesion (interindividual proximity decreased, aggression over food decreased, and play during feeding competition increased). These results support the hypothesis that outgroup threat elicits ingroup tolerance in chimpanzees. This suggests that in chimpanzees, like humans, competition between groups fosters group cohesion
Spanish-speaking caregiversâ use of referential labels with toddlers is a better predictor of later vocabulary than their use of referential gestures
Variation in how frequently caregivers engage with their children is associated with variation in childrenâs later language outcomes. One explanation for this link is that caregivers use both verbal behaviors, such as labels, and non-verbal behaviors, such as gestures, to help children establish reference to objects or events in the world. However, few studies have directly explored whether language outcomes are more strongly associated with referential behaviors that are expressed verbally, such as labels, or non-verbally, such as gestures, or whether both are equally predictive. Here, we observed caregivers from 42 Spanish-speaking families in the US engage with their 18-month-old children during 5-min lab-based, play sessions. Childrenâs language processing speed and vocabulary size were assessed when children were 25 months. Bayesian model comparisons assessed the extent to which the frequencies of caregiversâ referential labels, referential gestures, or labels and gestures together, were more strongly associated with childrenâs language outcomes than their total numbers of words, or overall talkativeness. The best-fitting models showed that children who heard more referential labels at 18 months were faster in language processing and had larger vocabularies at 25 months. Models including gestures, or labels and gestures together, showed weaker fits to the data. Caregiversâ total words predicted childrenâs language processing speed, but predicted vocabulary size less well. These results suggest that the frequency with which caregivers of 18-month-old children use referential labels, more so than referential gestures, is a critical feature of caregiver verbal engagement that contributes to language processing development and vocabulary growth
Loss of molecules in magneto-electrostatic traps due to nonadiabatic transitions
We analyze the dynamics of a paramagnetic, dipolar molecule in a generic
"magneto-electrostatic'' trap where both magnetic and electric fields may be
present. The potential energy that governs the dynamics of the molecules is
found using a reduced molecular model that incorporates the main features of
the system. We discuss the shape of the trapping potentials for different field
geometries, as well as the possibility of nonadiabatic transitions to untrapped
states, i.e., the analog of Majorana transitions in a quadrupole magnetic
atomic trap. Maximizing the lifetime of molecules in a trap is of great concern
in current experiments, and we assess the effect of nonadiabatic transitions on
obtainable trap lifetimes.Comment: 13 pages, 6 figure
Bo-NO-bouba-kiki: picture-word mapping but no spontaneous sound symbolic speech-shape mapping in a language trained bonobo
Humans share the ability to intuitively map âsharpâ or âroundâ pseudowords, such as âboubaâ versus âkikiâ, to abstract edgy versus round shapes, respectively. This effect, known as sound symbolism, appears early in human development. The phylogenetic origin of this phenomenon, however, is unclear: are humans the only species capable of experiencing correspondences between speech sounds and shapes, or could similar effects be observed in other animals? Thus far, evidence from an implicit matching experiment failed to find evidence of this sound symbolic matching in great apes, suggesting its human uniqueness. However, explicit tests of sound symbolism have never been conducted with nonhuman great apes. In the present study, a language-competent bonobo completed a cross-modal matching-to-sample task in which he was asked to match spoken English words to pictures, as well as âsharpâ or âroundâ pseudowords to shapes. Sound symbolic trials were interspersed among English words. The bonobo matched English words to pictures with high accuracy, but did not show any evidence of spontaneous sound symbolic matching. Our results suggest that speech exposure/comprehension alone cannot explain sound symbolism. This lends plausibility to the hypothesis that biological differences between human and nonhuman primates could account for the putative human specificity of this effect
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