Juliane Bräuer - Academia.edu (original) (raw)

Papers by Juliane Bräuer

Domestic dogs (Canis familiaris) and great apes from the genus Pan were tested on a series of obj... more Domestic dogs (Canis familiaris) and great apes from the genus Pan were tested on a series of object choice tasks. In each task, the location of hidden food was indicated for subjects by some kind of communicative, behavioral, or physical cue. On the basis of differences in the ecologies of these 2 genera, as well as on previous research, the authors hypothesized that dogs should be especially skillful in using human communicative cues such as the pointing gesture, whereas apes should be especially skillful in using physical, causal cues such as food in a cup making noise when it is shaken. The overall pattern of performance by the 2 genera strongly supported this social-dog, causal-ape hypothesis. This result is discussed in terms of apes' adaptations for complex, extractive foraging and dogs' adaptations, during the domestication process, for cooperative communication with humans.

American journal of primatology, 2015

There is now growing evidence that some animal species are able to plan for the future. For examp... more There is now growing evidence that some animal species are able to plan for the future. For example great apes save and exchange tools for future use. Here we raise the question whether chimpanzees, orangutans, and bonobos would produce tools for future use. Subjects only had access to a baited apparatus for a limited duration and therefore should use the time preceding this access to create the appropriate tools in order to get the rewards. The apes were tested in three conditions depending on the need for pre-prepared tools. Either eight tools, one tool or no tools were needed to retrieve the reward. The apes prepared tools in advance for future use and they produced them mainly in conditions when they were really needed. The fact that apes were able to solve this new task indicates that their planning skills are flexible. However, for the condition in which eight tools were needed, apes produced less than two tools per trial in advance. However, they used their chance to produce ...

Social Justice Research, 2012

ABSTRACT Humans have a sense of fairness, i.e. an interest in the ideal of equity. This sense all... more ABSTRACT Humans have a sense of fairness, i.e. an interest in the ideal of equity. This sense allows them to compare their own efforts and subsequent outcomes with those of others, and thus to evaluate and react to inequity. The question is whether our closest living relatives, the non-human primates, show the behavioural characteristics that might qualify as necessary components to a sense of fairness, such as inequity aversion. In this article, we review the five different experimental approaches to studying behaviours related to fairness in non-human primates, including their underlying logic and main findings that represent the current state of research in this field. In the critical condition of all these studies, a subject and a conspecific partner have either to invest different efforts or receive different outcomes while observing each other. The main question is whether—and how—subjects react to unequal situations that humans would perceive as ‘unfair’. Taken together, the results from all five approaches provide only weak evidence for a sense of fairness in non-human primates. Although apes and monkeys are attentive to what the partner is getting, they do not seem to be able or motivated to compare their own efforts and outcomes with those of others at a human level. Even though the debate is still on-going, we believe that a full sense of fairness is not essential for cooperation. Obviously, apes and monkeys are capable of solving problems cooperatively, without a strong, humanlike sense of fairness. They are mainly interested in maximizing their own benefit, regardless of what others may receive. It is thus possible that a sense of fairness only exists rudimentarily in non-human primates.

Science, 2007

We demonstrate the assembly of biohybrid materials from engineered tissues and synthetic polymer ... more We demonstrate the assembly of biohybrid materials from engineered tissues and synthetic polymer thin films. The constructs were built by culturing neonatal rat ventricular cardiomyocytes on polydimethylsiloxane thin films micropatterned with extracellular matrix proteins to promote spatially ordered, two-dimensional myogenesis. The constructs, termed muscular thin films, adopted functional, three-dimensional conformations when released from a thermally sensitive polymer substrate and were designed to perform biomimetic tasks by varying tissue architecture, thin-film shape, and electrical-pacing protocol. These centimeter-scale constructs perform functions as diverse as gripping, pumping, walking, and swimming with fine spatial and temporal control and generating specific forces as high as 4 millinewtons per square millimeter. M uscle cells are microscale linear actuators driven by the activation of actinmyosin motors, coordinated in space and time through excitation-contraction (EC) coupling (1, 2). Structure-function relations are conserved over several orders of spatial magnitude, from the sarcomere to the muscle bundle, by virtue of a hierarchical architecture. These architectures are achieved by morphogenesis programs that are responsible for coupling a broad range of processes, from sarcomeregenesis to the integration of the biochemical and electrical networks that support muscle function (1). Muscle actuation occurs over a wide range of frequencies (0 to~100 Hz), spatial dimensions (5 mm to ≥1 m), and force regimes (~5 mN to ≥1 kN) (3, 4). Artificial muscles can match certain temporal, spatial, or force regimes typical of biological muscle (5, 6), but they cannot fully replicate all of these capabilities, nor can they use the same high-density energy sources. Thus, engineered muscle remains an attractive method for building actuators and powering devices from the micro to macro scales.

Proceedings of the Royal Society B: Biological Sciences, 2006

Brosnan et al. (Brosnan, S. F. Schiff, H. C. & de... more Brosnan et al. (Brosnan, S. F. Schiff, H. C. & de Waal, F. B. M. 2005 Tolerance for inequity may increase with social closeness in chimpanzees. Proc. R. Soc. B272, 253-258) found that chimpanzees showed increased levels of rejection for less-preferred food when competitors received better food than themselves and postulated as an explanation inequity aversion. In the present study, we extended these findings by adding important control conditions, and we investigated whether inequity aversion could also be found in the other great ape species and whether it would be influenced by subjects' relationship with the competitor. In the present study, subjects showed a pattern of food rejection opposite to the subjects of the above study by Brosnan et al. (2005). Our apes ignored fewer food pieces and stayed longer in front of the experimenter when a conspecific received better food than themselves. Moreover, chimpanzees begged more vigorously when the conspecific got favoured food. The most plausible explanation for these results is the food expectation hypothesis - seeing another individual receive high-quality food creates the expectation of receiving the same food oneself - and not inequity aversion.

Journal of Veterinary Behavior: Clinical Applications and Research, 2009

Journal of the European Academy of Dermatology and Venereology, 1992

A 46-year-old woman presented with multiple seborrheic keratoses disseminated over her trunk and ... more A 46-year-old woman presented with multiple seborrheic keratoses disseminated over her trunk and thighs. A screening for internal malignancies revealed an adenocarcinoma of the colon that was successfully treated by surgery. During a follow-up period of 18 months, the seborrheic keratoses remained unchanged. There was no evidence of recurrence of the malignancy. We conclude that this case does not fulfill the criteria of the 'sign of Leser-TrClat'; according to present knowledge the existence of this cutaneous paraneoplastic syndrome cannot be taken as a certain indication. Patients with multiple seborrheic keratoses do not necessarily present internal malignancies.

Journal of Comparative Psychology, 2011

Journal of Comparative Psychology, 2006

Domestic dogs (Canis familiaris) and great apes from the genus Pan were tested on a series of obj... more Domestic dogs (Canis familiaris) and great apes from the genus Pan were tested on a series of object choice tasks. In each task, the location of hidden food was indicated for subjects by some kind of communicative, behavioral, or physical cue. On the basis of differences in the ecologies of these 2 genera, as well as on previous research, the authors hypothesized that dogs should be especially skillful in using human communicative cues such as the pointing gesture, whereas apes should be especially skillful in using physical, causal cues such as food in a cup making noise when it is shaken. The overall pattern of performance by the 2 genera strongly supported this social-dog, causal-ape hypothesis. This result is discussed in terms of apes' adaptations for complex, extractive foraging and dogs' adaptations, during the domestication process, for cooperative communication with humans.

Journal of Comparative Psychology, 2003

Twelve domestic dogs (Canis familiaris) were given a series of trials in which they were forbidde... more Twelve domestic dogs (Canis familiaris) were given a series of trials in which they were forbidden to take a piece of visible food. In some trials, the human continued to look at the dog throughout the trial (control condition), whereas in others, the human (a) left the room, (b) turned her back, (c) engaged in a distracting activity, or (d) closed her eyes. Dogs behaved in clearly different ways in most of the conditions in which the human did not watch them compared with the control condition, in which she did. In particular, when the human looked at them, dogs retrieved less food, approached it in a more indirect way, and sat (as opposed to laid down) more often than in the other conditions. Results are discussed in terms of domestic dogs' social-cognitive skills and their unique evolutionary and ontogenetic histories.

Journal of Comparative Psychology, 2005

Following the gaze direction of conspecifics is an adaptive skill that enables individuals to obt... more Following the gaze direction of conspecifics is an adaptive skill that enables individuals to obtain useful information about the location of food, predators, and group mates. In the current study, the authors compared the gaze-following skills of all 4 great ape species. In the 1st experiment, a human either looked to the ceiling or looked straight ahead. Individuals from all species reliably followed the human's gaze direction and sometimes even checked back when they found no target. In a 2nd experiment, the human looked behind some kind of barrier. Results showed that individuals from all species reliably put themselves in places from which they could see what the experimenter was looking at behind the barrier. These results support the hypothesis that great apes do not just orient to a target that another is oriented to, but they actually attempt to take the visual perspective of the other.

Behaviour, 2009

We investigated dogs' ability to take the visual perspective of humans. In the main study, each o... more We investigated dogs' ability to take the visual perspective of humans. In the main study, each of two toys was placed on the dog's side of two small barriers (one opaque, one transparent). In experimental conditions, a human sat on the opposite side of the barriers, such that she could see only the toy behind the transparent barrier. The experimenter then told the dog to 'Bring it here!' (without designating either toy in any way). In the Back Turned control E also sat on the opposite side but with her back turned so that she could see neither toy, and in the Same Side control she sat on the same side as the dog such that she could see both toys. When toys were differentiable dogs approached the toy behind the transparent barrier in experimental as compared to back turned and same side condition. Dogs did not differentiate between the two control conditions. In a second study dogs were not sensitive to what a human had or had not seen in the immediate past. These results suggest that, even in the absence of overt behavioural cues, dogs are sensitive to others visual access, even if that differs from their own.

Applied Animal Behaviour Science, 2013

ABSTRACT Here we investigate whether domestic dogs (Canis familiaris) engage in instrumental help... more ABSTRACT Here we investigate whether domestic dogs (Canis familiaris) engage in instrumental helping towards humans without special training. We hypothesized that dogs would help a human if the human's goal was made as obvious as possible. Therefore we used a set-up in which a human attempted to enter a compartment within a room (the "target room") in order to get a key. The dog could open the door to the target room by pushing a button. We varied the way in which the experimenter expressed how she wanted to enter the target room (reaching, pushing the door, communicating with the dog) and the relationship between human and dog (owner versus stranger). Dogs helped in two situations: (I) when the human pointed at the button and (2) when the humans communicated naturally to the dogs, i.e. without a predetermined series of actions. In these situations; dogs continued to open the door without receiving any reward. We therefore conclude that dogs are motivated to help and that an experimenter's natural behaviours facilitated the dogs' recognition of the human's goal. Interestingly the identity of the experimenter had no influence on the behaviour of the dogs.

Applied Animal Behaviour Science, 2004

Previous studies have shown that dogs have developed a special sensitivity to the communicative s... more Previous studies have shown that dogs have developed a special sensitivity to the communicative signals and attentional states of humans. The aim of the current study was to further investigate what dogs know about the visual perception of humans and themselves. In the first two experiments we investigated whether dogs were sensitive to the properties of barriers as blocking the visual access of humans. We presented dogs with a situation in which a human forbade them to take a piece of food, but the type and orientation of the barrier allowed the dog to take the food undetected in some conditions. Dogs differentiated between effective and ineffective barriers, based on their orientation or the particular features of the barriers such as size or the presence of window. In the third study we investigated whether dogs know about what they themselves have seen. We presented subjects with two boxes and placed food in one of them. In the Seen condition the location of the food was shown to the dogs while in the Unseen condition dogs were prevented from seeing the destination of the food. Before selecting one of the boxes by pressing a lever, dogs had the opportunity to seek extra information regarding the contents of the boxes, which would be particularly useful in the condition in which they had not seen where the food was hidden. Dogs rarely used the opportunity to seek information about the contents of the box before making their choice in any condition. Therefore, we found no evidence suggesting that dogs have access to what they themselves have seen, which contrasts with the positive evidence about visual perspective taking in others from the first two experiments and previous studies.

Applied Animal Behaviour Science, 2012

Domesticated animals show physical, behavioural and cognitive differences from their closest wild... more Domesticated animals show physical, behavioural and cognitive differences from their closest wild relatives. This may have resulted from the former's long and continued selection by humans throughout history, but in some cases it could just reflect developmental differences between wild and domestic animals, given that their environments usually differ significantly. In order to investigate possible effects of domestication and ontogeny on swine cognition, we tested wild boars and two groups of domestic pigs living in more and less enriched conditions. In an object choice paradigm subjects had to find food hidden in one of two containers. They received either a physical cue (i.e., the slope of the board hiding the food, the presence or absence of noise from a shaken container, the sight of a baited container changing position) or a human social cue (i.e., touching, pointing, gazing). According to the domestication hypothesis, given similar rearing conditions domestic pigs should perform better than wild boars when receiving social cues but worse when receiving physical cues. According to the developmental hypothesis, more experienced swine should perform better than less experienced swine both in the physical and in the social domain. Subjects performed better when provided with cues on which they had received adequate experience from their environment, thus providing support to the developmental hypothesis. We conclude by suggesting that specific experience on particular stimuli rather than general experience on a wider range of stimuli may explain swine ability to solve both social and physical tasks.

Animal Cognition, 2013

Cooperative hunting is a cognitively challenging activity since individuals have to coordinate mo... more Cooperative hunting is a cognitively challenging activity since individuals have to coordinate movements with a partner and at the same time react to the prey. Domestic dogs evolved from wolves, who engage in cooperative hunting regularly, but it is not clear whether dogs have kept their cooperative hunting skills. We presented pairs of dogs with a reward behind a fence with two openings in it. A sliding door operated by the experimenter could block one opening but not both simultaneously. The dogs needed to coordinate their actions, so that each was in front of a different opening, if one of them was to cross through and get food. All 24 dog pairs solved the problem.

Animal Cognition, 2007

Chimpanzee's perspective-taking abilities are currently disputed. Here we show that in some food ... more Chimpanzee's perspective-taking abilities are currently disputed. Here we show that in some food competition contexts, subordinate chimpanzees do take the visual perspective of dominant individuals, preferentially targeting a hidden piece of the food that the dominant cannot see over a piece that is visible to both individuals. However, the space where the animals compete is critical in determining whether subjects demonstrate this skill. We suggest that competition intensity, as mediated by these spatial factors, may play an important role in determining the strategy chimpanzees utilize in competitive contexts. Since some strategies may not require visual perspective taking in order to be successful, chimpanzees may not always demonstrate this skill. DiVerences in spatial arrangement may therefore account for the conXicting results of past studies.

Domestic dogs (Canis familiaris) and great apes from the genus Pan were tested on a series of obj... more Domestic dogs (Canis familiaris) and great apes from the genus Pan were tested on a series of object choice tasks. In each task, the location of hidden food was indicated for subjects by some kind of communicative, behavioral, or physical cue. On the basis of differences in the ecologies of these 2 genera, as well as on previous research, the authors hypothesized that dogs should be especially skillful in using human communicative cues such as the pointing gesture, whereas apes should be especially skillful in using physical, causal cues such as food in a cup making noise when it is shaken. The overall pattern of performance by the 2 genera strongly supported this social-dog, causal-ape hypothesis. This result is discussed in terms of apes' adaptations for complex, extractive foraging and dogs' adaptations, during the domestication process, for cooperative communication with humans.

American journal of primatology, 2015

There is now growing evidence that some animal species are able to plan for the future. For examp... more There is now growing evidence that some animal species are able to plan for the future. For example great apes save and exchange tools for future use. Here we raise the question whether chimpanzees, orangutans, and bonobos would produce tools for future use. Subjects only had access to a baited apparatus for a limited duration and therefore should use the time preceding this access to create the appropriate tools in order to get the rewards. The apes were tested in three conditions depending on the need for pre-prepared tools. Either eight tools, one tool or no tools were needed to retrieve the reward. The apes prepared tools in advance for future use and they produced them mainly in conditions when they were really needed. The fact that apes were able to solve this new task indicates that their planning skills are flexible. However, for the condition in which eight tools were needed, apes produced less than two tools per trial in advance. However, they used their chance to produce ...

Social Justice Research, 2012

ABSTRACT Humans have a sense of fairness, i.e. an interest in the ideal of equity. This sense all... more ABSTRACT Humans have a sense of fairness, i.e. an interest in the ideal of equity. This sense allows them to compare their own efforts and subsequent outcomes with those of others, and thus to evaluate and react to inequity. The question is whether our closest living relatives, the non-human primates, show the behavioural characteristics that might qualify as necessary components to a sense of fairness, such as inequity aversion. In this article, we review the five different experimental approaches to studying behaviours related to fairness in non-human primates, including their underlying logic and main findings that represent the current state of research in this field. In the critical condition of all these studies, a subject and a conspecific partner have either to invest different efforts or receive different outcomes while observing each other. The main question is whether—and how—subjects react to unequal situations that humans would perceive as ‘unfair’. Taken together, the results from all five approaches provide only weak evidence for a sense of fairness in non-human primates. Although apes and monkeys are attentive to what the partner is getting, they do not seem to be able or motivated to compare their own efforts and outcomes with those of others at a human level. Even though the debate is still on-going, we believe that a full sense of fairness is not essential for cooperation. Obviously, apes and monkeys are capable of solving problems cooperatively, without a strong, humanlike sense of fairness. They are mainly interested in maximizing their own benefit, regardless of what others may receive. It is thus possible that a sense of fairness only exists rudimentarily in non-human primates.

Science, 2007

We demonstrate the assembly of biohybrid materials from engineered tissues and synthetic polymer ... more We demonstrate the assembly of biohybrid materials from engineered tissues and synthetic polymer thin films. The constructs were built by culturing neonatal rat ventricular cardiomyocytes on polydimethylsiloxane thin films micropatterned with extracellular matrix proteins to promote spatially ordered, two-dimensional myogenesis. The constructs, termed muscular thin films, adopted functional, three-dimensional conformations when released from a thermally sensitive polymer substrate and were designed to perform biomimetic tasks by varying tissue architecture, thin-film shape, and electrical-pacing protocol. These centimeter-scale constructs perform functions as diverse as gripping, pumping, walking, and swimming with fine spatial and temporal control and generating specific forces as high as 4 millinewtons per square millimeter. M uscle cells are microscale linear actuators driven by the activation of actinmyosin motors, coordinated in space and time through excitation-contraction (EC) coupling (1, 2). Structure-function relations are conserved over several orders of spatial magnitude, from the sarcomere to the muscle bundle, by virtue of a hierarchical architecture. These architectures are achieved by morphogenesis programs that are responsible for coupling a broad range of processes, from sarcomeregenesis to the integration of the biochemical and electrical networks that support muscle function (1). Muscle actuation occurs over a wide range of frequencies (0 to~100 Hz), spatial dimensions (5 mm to ≥1 m), and force regimes (~5 mN to ≥1 kN) (3, 4). Artificial muscles can match certain temporal, spatial, or force regimes typical of biological muscle (5, 6), but they cannot fully replicate all of these capabilities, nor can they use the same high-density energy sources. Thus, engineered muscle remains an attractive method for building actuators and powering devices from the micro to macro scales.

Proceedings of the Royal Society B: Biological Sciences, 2006

Brosnan et al. (Brosnan, S. F. Schiff, H. C. & de... more Brosnan et al. (Brosnan, S. F. Schiff, H. C. & de Waal, F. B. M. 2005 Tolerance for inequity may increase with social closeness in chimpanzees. Proc. R. Soc. B272, 253-258) found that chimpanzees showed increased levels of rejection for less-preferred food when competitors received better food than themselves and postulated as an explanation inequity aversion. In the present study, we extended these findings by adding important control conditions, and we investigated whether inequity aversion could also be found in the other great ape species and whether it would be influenced by subjects' relationship with the competitor. In the present study, subjects showed a pattern of food rejection opposite to the subjects of the above study by Brosnan et al. (2005). Our apes ignored fewer food pieces and stayed longer in front of the experimenter when a conspecific received better food than themselves. Moreover, chimpanzees begged more vigorously when the conspecific got favoured food. The most plausible explanation for these results is the food expectation hypothesis - seeing another individual receive high-quality food creates the expectation of receiving the same food oneself - and not inequity aversion.

Journal of Veterinary Behavior: Clinical Applications and Research, 2009

Journal of the European Academy of Dermatology and Venereology, 1992

A 46-year-old woman presented with multiple seborrheic keratoses disseminated over her trunk and ... more A 46-year-old woman presented with multiple seborrheic keratoses disseminated over her trunk and thighs. A screening for internal malignancies revealed an adenocarcinoma of the colon that was successfully treated by surgery. During a follow-up period of 18 months, the seborrheic keratoses remained unchanged. There was no evidence of recurrence of the malignancy. We conclude that this case does not fulfill the criteria of the 'sign of Leser-TrClat'; according to present knowledge the existence of this cutaneous paraneoplastic syndrome cannot be taken as a certain indication. Patients with multiple seborrheic keratoses do not necessarily present internal malignancies.

Journal of Comparative Psychology, 2011

Journal of Comparative Psychology, 2006

Domestic dogs (Canis familiaris) and great apes from the genus Pan were tested on a series of obj... more Domestic dogs (Canis familiaris) and great apes from the genus Pan were tested on a series of object choice tasks. In each task, the location of hidden food was indicated for subjects by some kind of communicative, behavioral, or physical cue. On the basis of differences in the ecologies of these 2 genera, as well as on previous research, the authors hypothesized that dogs should be especially skillful in using human communicative cues such as the pointing gesture, whereas apes should be especially skillful in using physical, causal cues such as food in a cup making noise when it is shaken. The overall pattern of performance by the 2 genera strongly supported this social-dog, causal-ape hypothesis. This result is discussed in terms of apes' adaptations for complex, extractive foraging and dogs' adaptations, during the domestication process, for cooperative communication with humans.

Journal of Comparative Psychology, 2003

Twelve domestic dogs (Canis familiaris) were given a series of trials in which they were forbidde... more Twelve domestic dogs (Canis familiaris) were given a series of trials in which they were forbidden to take a piece of visible food. In some trials, the human continued to look at the dog throughout the trial (control condition), whereas in others, the human (a) left the room, (b) turned her back, (c) engaged in a distracting activity, or (d) closed her eyes. Dogs behaved in clearly different ways in most of the conditions in which the human did not watch them compared with the control condition, in which she did. In particular, when the human looked at them, dogs retrieved less food, approached it in a more indirect way, and sat (as opposed to laid down) more often than in the other conditions. Results are discussed in terms of domestic dogs' social-cognitive skills and their unique evolutionary and ontogenetic histories.

Journal of Comparative Psychology, 2005

Following the gaze direction of conspecifics is an adaptive skill that enables individuals to obt... more Following the gaze direction of conspecifics is an adaptive skill that enables individuals to obtain useful information about the location of food, predators, and group mates. In the current study, the authors compared the gaze-following skills of all 4 great ape species. In the 1st experiment, a human either looked to the ceiling or looked straight ahead. Individuals from all species reliably followed the human's gaze direction and sometimes even checked back when they found no target. In a 2nd experiment, the human looked behind some kind of barrier. Results showed that individuals from all species reliably put themselves in places from which they could see what the experimenter was looking at behind the barrier. These results support the hypothesis that great apes do not just orient to a target that another is oriented to, but they actually attempt to take the visual perspective of the other.

Behaviour, 2009

We investigated dogs' ability to take the visual perspective of humans. In the main study, each o... more We investigated dogs' ability to take the visual perspective of humans. In the main study, each of two toys was placed on the dog's side of two small barriers (one opaque, one transparent). In experimental conditions, a human sat on the opposite side of the barriers, such that she could see only the toy behind the transparent barrier. The experimenter then told the dog to 'Bring it here!' (without designating either toy in any way). In the Back Turned control E also sat on the opposite side but with her back turned so that she could see neither toy, and in the Same Side control she sat on the same side as the dog such that she could see both toys. When toys were differentiable dogs approached the toy behind the transparent barrier in experimental as compared to back turned and same side condition. Dogs did not differentiate between the two control conditions. In a second study dogs were not sensitive to what a human had or had not seen in the immediate past. These results suggest that, even in the absence of overt behavioural cues, dogs are sensitive to others visual access, even if that differs from their own.

Applied Animal Behaviour Science, 2013

ABSTRACT Here we investigate whether domestic dogs (Canis familiaris) engage in instrumental help... more ABSTRACT Here we investigate whether domestic dogs (Canis familiaris) engage in instrumental helping towards humans without special training. We hypothesized that dogs would help a human if the human's goal was made as obvious as possible. Therefore we used a set-up in which a human attempted to enter a compartment within a room (the "target room") in order to get a key. The dog could open the door to the target room by pushing a button. We varied the way in which the experimenter expressed how she wanted to enter the target room (reaching, pushing the door, communicating with the dog) and the relationship between human and dog (owner versus stranger). Dogs helped in two situations: (I) when the human pointed at the button and (2) when the humans communicated naturally to the dogs, i.e. without a predetermined series of actions. In these situations; dogs continued to open the door without receiving any reward. We therefore conclude that dogs are motivated to help and that an experimenter's natural behaviours facilitated the dogs' recognition of the human's goal. Interestingly the identity of the experimenter had no influence on the behaviour of the dogs.

Applied Animal Behaviour Science, 2004

Previous studies have shown that dogs have developed a special sensitivity to the communicative s... more Previous studies have shown that dogs have developed a special sensitivity to the communicative signals and attentional states of humans. The aim of the current study was to further investigate what dogs know about the visual perception of humans and themselves. In the first two experiments we investigated whether dogs were sensitive to the properties of barriers as blocking the visual access of humans. We presented dogs with a situation in which a human forbade them to take a piece of food, but the type and orientation of the barrier allowed the dog to take the food undetected in some conditions. Dogs differentiated between effective and ineffective barriers, based on their orientation or the particular features of the barriers such as size or the presence of window. In the third study we investigated whether dogs know about what they themselves have seen. We presented subjects with two boxes and placed food in one of them. In the Seen condition the location of the food was shown to the dogs while in the Unseen condition dogs were prevented from seeing the destination of the food. Before selecting one of the boxes by pressing a lever, dogs had the opportunity to seek extra information regarding the contents of the boxes, which would be particularly useful in the condition in which they had not seen where the food was hidden. Dogs rarely used the opportunity to seek information about the contents of the box before making their choice in any condition. Therefore, we found no evidence suggesting that dogs have access to what they themselves have seen, which contrasts with the positive evidence about visual perspective taking in others from the first two experiments and previous studies.

Applied Animal Behaviour Science, 2012

Domesticated animals show physical, behavioural and cognitive differences from their closest wild... more Domesticated animals show physical, behavioural and cognitive differences from their closest wild relatives. This may have resulted from the former's long and continued selection by humans throughout history, but in some cases it could just reflect developmental differences between wild and domestic animals, given that their environments usually differ significantly. In order to investigate possible effects of domestication and ontogeny on swine cognition, we tested wild boars and two groups of domestic pigs living in more and less enriched conditions. In an object choice paradigm subjects had to find food hidden in one of two containers. They received either a physical cue (i.e., the slope of the board hiding the food, the presence or absence of noise from a shaken container, the sight of a baited container changing position) or a human social cue (i.e., touching, pointing, gazing). According to the domestication hypothesis, given similar rearing conditions domestic pigs should perform better than wild boars when receiving social cues but worse when receiving physical cues. According to the developmental hypothesis, more experienced swine should perform better than less experienced swine both in the physical and in the social domain. Subjects performed better when provided with cues on which they had received adequate experience from their environment, thus providing support to the developmental hypothesis. We conclude by suggesting that specific experience on particular stimuli rather than general experience on a wider range of stimuli may explain swine ability to solve both social and physical tasks.

Animal Cognition, 2013

Cooperative hunting is a cognitively challenging activity since individuals have to coordinate mo... more Cooperative hunting is a cognitively challenging activity since individuals have to coordinate movements with a partner and at the same time react to the prey. Domestic dogs evolved from wolves, who engage in cooperative hunting regularly, but it is not clear whether dogs have kept their cooperative hunting skills. We presented pairs of dogs with a reward behind a fence with two openings in it. A sliding door operated by the experimenter could block one opening but not both simultaneously. The dogs needed to coordinate their actions, so that each was in front of a different opening, if one of them was to cross through and get food. All 24 dog pairs solved the problem.

Animal Cognition, 2007

Chimpanzee's perspective-taking abilities are currently disputed. Here we show that in some food ... more Chimpanzee's perspective-taking abilities are currently disputed. Here we show that in some food competition contexts, subordinate chimpanzees do take the visual perspective of dominant individuals, preferentially targeting a hidden piece of the food that the dominant cannot see over a piece that is visible to both individuals. However, the space where the animals compete is critical in determining whether subjects demonstrate this skill. We suggest that competition intensity, as mediated by these spatial factors, may play an important role in determining the strategy chimpanzees utilize in competitive contexts. Since some strategies may not require visual perspective taking in order to be successful, chimpanzees may not always demonstrate this skill. DiVerences in spatial arrangement may therefore account for the conXicting results of past studies.