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Complex novel tasks are often used in animal cognition research to allow discrimination between various learning mechanisms. Successful performance relies on the capacity to identify informational cues from features in the environment. Additionally, observational learning is often considered more beneficial for survival than individual learning. Despite the importance of controlling task complexity, it can often be challenging to operationalize. This study investigated whether jackdaws, a highly social corvid species, can learn to drop stones inside a tube to release a reward after observing a trained conspecific. Additionally, it aimed to identify the underlying learning mechanisms and to detect the informational cues triggering learning. A research design was developed to highlight different aspects of the required action sequence. Experimental conditions included a conspecific model demonstrating the full sequence, parts of the sequence, consuming the reward without solving the task, and consuming the reward after the solution was demonstrated without a visible model. None of the 12 naïve jackdaws solved the task in pretests. Two subjects started solving in test sessions and they developed modified versions of the demonstrated action. Observing the full action sequence performed by a conspecific seemed to trigger learning. The majority of the subjects exhibited changes in their stone-oriented behavior, most likely due to stimulus and/or local enhancement. As predicted, jackdaws were influenced by conspecific model demonstrations when manipulating a complex novel foraging task. Factors contributing to the apparent task difficulty and directions for future studies are discussed within a tri-dimensional framework including the task, setup, and individuals.

Information about novel environments or foods can be gathered via individual or social learning. Whereas individual learning is assumed to be more costly and less effective than social learning, it also yields more detailed information. Juveniles are often found to be more explorative than adults. Still under the protection of their parents, this allows them to sample their environment in preparation for later in life. We tested individual and social learning in jackdaws (Corvus monedula) of different age groups in a semi-natural group setting. Juvenile and adult jackdaws differed in their learning propensity. Juveniles spent more time at the test apparatus, were more explorative, and caused the apparatus to open. Almost all the openings at the apparatus matched the demonstrated method. As more observers became available, the juveniles could observe each other. Individuals preferentially watched successful conspecifics and those they could scrounge food from. Lower-ranking individuals tended to watch higher ranking ones; higher ranking individuals preferentially watched conspecifics of similar rank. The control group did not manipulate the apparatus. Due to the lack of this baseline, it was difficult to determine for certain whether the opening technique was acquired via individual or social learning. We conclude that if social learning played a role, the underlying mechanism was most likely local or stimulus enhancement. It is, however, more parsimonious to assume that juveniles were more explorative than adults, and that their opening technique was potentially easier to acquire than the one demonstrated to adults.

International audience; Allogrooming in primates serves not only a hygienic function, but also plays a crucial role in maintaining strong affiliative bonds between group members, which in turn, underpin the emergence of cooperative behavior. In contrast, although allopreening occurs in many avian species, we know little about its social functions. Our study addresses this issue by investigating allopreening in a broad comparative data set including six corvid and nine parrot species. We assessed whether rates of allopreening initiations, proportion of time spent allopreening, and the number of grooming partners in captive group-housed birds were comparable to patterns observed in captive chimpanzees and bonobos. While parrots and corvids were found to have similar rates of social grooming to bonobos and chimpanzees, Pan species dedicated significantly more time to social grooming. Animals in larger groups had more grooming partners, but when controlling for the number of potential partners, birds tended to have fewer grooming interaction partners than Pan species. We then investigated whether allopreening in parrots and corvids was predicted by behavioral markers of affiliative social bonds (close physical proximity, active feeding, and low levels of agonistic behavior). Results revealed that providing allopreening to a partner was significantly predicted by often being in close proximity, but not engagement in active feeding or agonistic behavior. We examined the region allopreened in a subset of species and found that preening a partner's head was predicted by both close physical proximity and active feeding, while body allopreening was only predicted by close physical proximity. Head preening may confer more hygienic benefits to recipients, and thus, may be more selectively provided to valued partners. Results support the hypothesis that allopreening in corvids and parrots helps maintain social bonds with an individual's most important social partners, showing some similarities to allogrooming in primates.

Social learning is a powerful mechanism of information acquisition and can be found in various species. According to the type of information transmitted, animals may change their motivation to perform actions, shift their perception/attention to relevant stimuli, associate other individuals' behaviours with particular stimuli/events or learn to perform ‘novel’ behaviours. The latter is referred to as imitation and has been considered a cognitively demanding mechanism necessary for high-fidelity copying, which may or may not occur in nonhuman animals. We tested the ability of 20 juvenile ravens to imitate an action demonstrated by a human experimenter. Birds of two test groups could observe a familiar human executing one of two opening techniques at an artificial fruit apparatus (horizontal or vertical hand movements directed towards the same location), whereas birds of a control group observed the human touching but not opening the apparatus. Ravens of both test groups tended to use the same direction of movements as observed, when they opened the apparatus themselves with their beak. Comparison with the control group revealed that ravens had a predisposition to manipulate the apparatus by pecking. Hence, observers of vertical hand movements most likely strengthened their initial preference for executing peck movements towards an item enclosing food, whereas observers of horizontal hand movements started to apply beak/head movements that hardly occur during foraging and are ‘novel’ to this context. Juvenile ravens are thus capable of imitating simple motor actions, even though they may use a different body part to execute the behaviours than human demonstrators. published

Purpose The aim of this study was to evaluate the effectiveness and safety of hyaluronic acid (HA) dermal filler when used in the face for medical reconstructive purposes. Patients and methods Adult patients with moderately severe facial lipoatrophy (FLA), morphological asymmetry (MA) of the face, or debilitating scars (DS) on the face were included in a prospective, noncomparative, multicenter, postmarket clinical follow-up study. All patients were treated with an HA filler (Princess® FILLER), which was injected intradermally on study Day 1, with optional touch-up 2 weeks later. The effectiveness of the treatment was evaluated at Weeks 4 and 24, using a six-grade scale ranging from "excellent" to "worsening". The assessments were conducted by both the investigator and the patient and, at Week 4, by the independent photography reviewer as well. Adverse events were collected at each visit. Results Fifty-three patients were included in the study (FLA 23, MA 17, and DS 13), and 46 patients completed a 6-month follow-up (FLA 20, MA 15, and DS 11). At Week 4 (primary endpoint), the overall treatment success rate was 100% (FLA), 100% (MA), and 94% (DS), based on assessments made by the investigator, patients, and the independent reviewer, respectively. In most patients (~95%), the effect was sustained over 6 months. Treatment-related adverse events were reported in five patients (9%) and included injection site hematoma, injection site pain, and headache. Conclusion Dermal filling with HA gel is a viable treatment option for the correction of various deformities of the face resulting from FLA, MA, or DS.

Purpose The aim of this study was to evaluate the effectiveness and safety of hyaluronic acid (HA) dermal filler when used in the face for medical reconstructive purposes. Patients and methods Adult patients with moderately severe facial lipoatrophy (FLA), morphological asymmetry (MA) of the face, or debilitating scars (DS) on the face were included in a prospective, noncomparative, multicenter, postmarket clinical follow-up study. All patients were treated with an HA filler (Princess® FILLER), which was injected intradermally on study Day 1, with optional touch-up 2 weeks later. The effectiveness of the treatment was evaluated at Weeks 4 and 24, using a six-grade scale ranging from “excellent” to “worsening”. The assessments were conducted by both the investigator and the patient and, at Week 4, by the independent photography reviewer as well. Adverse events were collected at each visit. Results Fifty-three patients were included in the study (FLA 23, MA 17, and DS 13), and 46 patients completed a 6-month follow-up (FLA 20, MA 15, and DS 11). At Week 4 (primary endpoint), the overall treatment success rate was 100% (FLA), 100% (MA), and 94% (DS), based on assessments made by the investigator, patients, and the independent reviewer, respectively. In most patients (~95%), the effect was sustained over 6 months. Treatment-related adverse events were reported in five patients (9%) and included injection site hematoma, injection site pain, and headache. Conclusion Dermal filling with HA gel is a viable treatment option for the correction of various deformities of the face resulting from FLA, MA, or DS.

Background Soft tissue fillers are typically used for rejuvenating an aging face; they are also employed in the treatment of certain pathologic conditions, including facial lipoatrophy, morphological asymmetry, and debilitating scars. Aims The aim of this clinical study was to evaluate the effectiveness and safety of Princess® Volume (PV) in patients with facial lipoatrophy (FLA), morphological asymmetry (MA), or debilitating scars (DS). Patients/methods This prospective, noncomparative, multicenter clinical study consisted of five visits spread across 36 weeks. Up to 60 adult patients suffering from moderate facial lipoatrophy, facial morphological asymmetry, or debilitating scars on the face were to be included. All patients were treated with an HA filler (PV). Results At Week 4, the treatment success rate in the SP was 98% (95% CI [90.4%, 100%]), as assessed by both the investigators and the patients. According to the independent reviewer, the success rate was 93% (95% CI [82.7%, 98.0%]). At Week 24, the effect was maintained in most patients, with success rates of 80% as evaluated by the investigator and 79% by the patient (95% CI [67.6%, 89.8%] and [65.6%, 88.4%], respectively). At Week 36, success rates dropped to 61% as assessed by the investigator and 59% by the patient (95% CI [46.8%, 73.5%] and [45.0%, 71.9%], respectively). Conclusions The clinical study has proven that Princess® Volume is a safe and effective therapeutic solution for the correction of soft tissue defects in FLA and facial MA, but limited success rate to DS.

The research was funded by a FP7-PEOPLE-2013-IRSES research staff exchange grant to TB, SH, OG and ASG. OG was additionally supported by Gu227/16-1 and IF by an FWF grant (Y366-B17) to TB. Establishment in urbanized environments is associated with changes in physiology, behaviour, and problem-solving. We compared the speed of learning in urban and rural female common mynas, Acridotheres tristis, using a standard visual discrimination task followed by a reversal learning phase. We also examined how quickly each bird progressed through different stages of learning, including sampling and acquisition within both initial and reversal learning, and persistence following reversal. Based on their reliance on very different food resources, we expected urban mynas to learn and reversal learn more quickly but to sample new contingencies for proportionately longer before learning them. When quantified from first presentation to criterion achievement, urban mynas took more 20-trial blocks to learn the initial discrimination, as well as the reversed contingency, than rural mynas. More detailed analyses at the level of stage revealed that this was because urban mynas explored the novel cue-outcome contingencies for longer, and despite transitioning faster through subsequent acquisition, remained overall slower than rural females. Our findings draw attention to fine adjustments in learning strategies in response to urbanization and caution against interpreting the speed to learn a task as a reflection of cognitive ability. Postprint

Social comparisons are a fundamental characteristic of human behaviour, yet relatively little is known about their evolutionary foundations. Adapting the co-acting paradigm from human research (Seta in J Pers Soc Psychol 42:281–291, 1982. doi:10.1037//0022-3514.42.2.281), we examined how the performance of a partner influenced subjects’ performance in long-tailed macaques (Macaca fascicularis). Using parallel testing in touch screen setups in which subjects had to discriminate familiar and novel photographs of men and women, we investigated whether accuracy and reaction time were influenced by partner performance and relationship quality (affiliate vs. non-affiliate). Auditory feedback about the alleged performance of the co-actor was provided via playback; partner performance was either moderately or extremely better or worse than subject performance. We predicted that subjects would assimilate to moderately different comparison standards as well as to affiliates and contrast away from extreme standards and non-affiliates. Subjects instantly generalized to novel pictures. While accuracy was not affected by any of the factors, long reaction times occurred more frequently when subjects were tested with a non-affiliate who was performing worse, compared to one who was doing better than them (80 % quantile worse: 5.1, better: 4.3 s). For affiliate co-actors, there was no marked effect (worse: 4.4, better: 4.6 s). In a control condition with no auditory feedback, subjects performed somewhat better in the presence of affiliates (M = 77.8 % correct) compared to non-affiliates (M = 71.1 %), while reaction time was not affected. Apparently, subjects were sensitive to partner identity and performance, yet variation in motivation rather than assimilation and contrast effects may account for the observed effects. Electronic supplementary material The online version of this article (doi:10.1007/s10071-015-0943-4) contains supplementary material, which is available to authorized users.

For many decades, researchers have tried to get a glimpse into the “folk physies” of animals, that is, their common sense understanding of how the world works, as well as why it works in the way it does (e.g., Kohler 1927). It has been suggested that animals use a variety of cognitive strategies in understanding such things as space, tools, object categories, quantities, and perhaps causality. Significantly later, this focus of research has been complemented with studies on “folk psychology”, that is, what animals understand about the behavior and perhaps mental lives of conspecifics in interactions involving cooperation, competition, communication, and social learning (e.g., Premack and Woodruff 1978). However, in both fields of research, we are far from a common agreement of what animals really understand when they are engaged in adapting or modifying their environment, in their physical or social form, for their own sake. While some researchers believe that many large-brained animals develop an increasing ability to understand causal relationships on accumulating experience (Fujita, this volume; Hauser 2000; Rumbaugh et al. 2000), others warn to over-interpret the animal’s apprehension of cause-effect relations underlying the mainpulation of animate or inanimate objects (Heyes 1998; Povinelli 2000; Tomasello and Call 1997; Visalberghi and Tomasello 1998).

Reasoning by exclusion, i.e. the ability to understand that if there are only two possibilities and if it is not A, it must be B, has been a topic of great interest in recent comparative cognition research. Many studies have investigated this ability, employing different methods, but rarely exploring concurrent decision processes underlying choice behaviour of non-human animals encountering inconsistent or incomplete information. Here, we employed a novel training and test method in order to perform an in-depth analysis of the underlying processes. Importantly, to discourage the explorative behaviour of the kea, a highly neophilic species, the training included a large amount of novel, unrewarded stimuli. The subsequent test consisted of 30 sessions with different sequences of four test trials. In these test trials, we confronted the kea with novel stimuli that were paired with either the rewarded or unrewarded training stimuli or with the novel stimuli of previous test trials. Once habituated to novelty, eight out of fourteen kea tested responded to novel stimuli by inferring their contingency via logical exclusion of the alternative. One individual inferred predominantly in this way, while other response strategies, such as one trial learning, stimulus preferences and avoiding the negative stimulus also guided the responses of the remaining individuals. Interestingly, the difficulty of the task had no influence on the test performance. We discuss the implications of these findings for the current hypotheses about the emergence of inferential reasoning in some avian species, considering causal links to brain size, feeding ecology and social complexity.