A comparison of personality traits of gifted word learner and typical border collies.

While personality and cognition are distinct domains, some personality traits may affect the capacity for problem-solving. It was suggested that there is a positive association between the Playfulness trait and problem-solving performance in humans. Studies on giftedness (extremely good capacity in the case of a specific skill), typically aimed to reveal the genetic, experiential, and mental origins of such extreme inter-individual variation. We exploited recent findings on giftedness in a specific cognitive skill, object label learning, in dogs to explore the potential association between this exceptional skill and personality traits. We administered the Dog Personality Questionnaire to 21 gifted dog owners and compared the personality traits of their dogs to those of matched samples of 43 Hungarian and 101 Austrian typical dogs, i.e., dogs lacking this exceptional capacity. Since most Gifted Word Learner dogs are Border collies, we restricted our analysis to dogs of this breed. We hypothesized that the Gifted Word Learner dogs may show higher levels of Playfulness. As expected, we found that the gifted Border collies were rated as more playful than both the Hungarian and Austrian typical ones. Our results suggest that an extremely high level of Playfulness is associated with giftedness in a specific cognitive trait in dogs: the capacity to learn object verbal labels, thus opening new possibilities for comparative research on the relationship between giftedness and personality.

Movement and vocal intonation together evoke social referencing in companion dogs when confronted with a suspicious stranger.

Dogs have been claimed to engage in social referencing by responding in a way that corresponded with their owners' reaction in some contexts. We aimed to assess how owners' actions affect family dogs' behaviour in two ambiguous lifelike situations. In Experiment 1, two groups were tested; in the suspicious owner (SO) group, owners behaved suspiciously (N = 25), in the reassuring owner (RO) group, owners behaved in a reassuring manner (N = 28) facing a 'threatening stranger'. The sitting owners provided voice intonation and body posture changes as cues for the dogs when the stranger entered the room. Dogs looked longer at the owners and stayed longer near them in the SO group but their tendency to approach the stranger did not differ between the groups. Although the owners' behaviours seemed to have relevant effects on dogs' responses, we note that these looking and proximity seeking behaviours might also be explained by reactions to the owners' behaviour alone. In Experiment 2, all dogs (N = 19) were tested in both the SO and RO conditions in a slightly different procedure. Depending on the condition, owners took one step forward/backward and spoke happily/worryingly. The procedural differences and the larger distance between the stranger and the owner allowed the dog more time to perceive the behaviour of both the stranger and the owner, which made the distinction between alternative explanations for the dogs' behaviour easier to interpret. Dogs spent more time behind their owners in the SO condition and more dogs approached the stranger in the RO condition. Dogs' avoidance of the stranger when the owner behaved suspiciously and their tendency to approach the stranger only when the owner displayed positive emotions, can be best explained by social referencing.

Dog growls express various contextual and affective content for human listeners.

Vocal expressions of emotions follow simple rules to encode the inner state of the caller into acoustic parameters, not just within species, but also in cross-species communication. Humans use these structural rules to attribute emotions to dog vocalizations, especially to barks, which match with their contexts. In contrast, humans were found to be unable to differentiate between playful and threatening growls, probably because single growls' aggression level was assessed based on acoustic size cues. To resolve this contradiction, we played back natural growl bouts from three social contexts (food guarding, threatening and playing) to humans, who had to rate the emotional load and guess the context of the playbacks. Listeners attributed emotions to growls according to their social contexts. Within threatening and playful contexts, bouts with shorter, slower pulsing growls and showing smaller apparent body size were rated to be less aggressive and fearful, but more playful and happy. Participants associated the correct contexts with the growls above chance. Moreover, women and participants experienced with dogs scored higher in this task. Our results indicate that dogs may communicate honestly their size and inner state in a serious contest situation, while manipulatively in more uncertain defensive and playful contexts.

Neural mechanisms for lexical processing in dogs.

During speech processing, human listeners can separately analyze lexical and intonational cues to arrive at a unified representation of communicative content. The evolution of this capacity can be best investigated by comparative studies. Using functional magnetic resonance imaging, we explored whether and how dog brains segregate and integrate lexical and intonational information. We found a left-hemisphere bias for processing meaningful words, independently of intonation; a right auditory brain region for distinguishing intonationally marked and unmarked words; and increased activity in primary reward regions only when both lexical and intonational information were consistent with praise. Neural mechanisms to separately analyze and integrate word meaning and intonation in dogs suggest that this capacity can evolve in the absence of language.

Timing and presence of an attachment person affect sensitivity of aggression tests in shelter dogs.

Different test series have been developed and used to measure behaviour in shelter dogs in order to reveal individuals not suitable for re-homing due to their aggressive tendencies. However, behavioural tests previously validated on pet dogs seem to have relatively low predictability in the case of shelter dogs. Here, we investigate the potential effects of (1) timing of the behaviour testing and (2) presence of a human companion on dogs' aggressive behaviour. In Study I, shelter dogs (n=25) showed more aggression when tested in a short test series two weeks after they had been placed in the shelter compared to their responses in the same test performed 1-2 days after arrival. In Study II, the occurrence of aggressive behaviour was more probable in pet dogs (n=50) in the presence than in the absence of their passive owner. We conclude that the sensitivity of aggression tests for shelter dogs can be increased by running the test in the presence of a caretaker, and after some period of acclimatisation to the new environment. This methodology could also provide better chances for successful adoption.

Sensing sociality in dogs: what may make an interactive robot social?

This study investigated whether dogs would engage in social interactions with an unfamiliar robot, utilize the communicative signals it provides and to examine whether the level of sociality shown by the robot affects the dogs' performance. We hypothesized that dogs would react to the communicative signals of a robot more successfully if the robot showed interactive social behaviour in general (towards both humans and dogs) than if it behaved in a machinelike, asocial way. The experiment consisted of an interactive phase followed by a pointing session, both with a human and a robotic experimenter. In the interaction phase, dogs witnessed a 6-min interaction episode between the owner and a human experimenter and another 6-min interaction episode between the owner and the robot. Each interaction episode was followed by the pointing phase in which the human/robot experimenter indicated the location of hidden food by using pointing gestures (two-way choice test). The results showed that in the interaction phase, the dogs' behaviour towards the robot was affected by the differential exposure. Dogs spent more time staying near the robot experimenter as compared to the human experimenter, with this difference being even more pronounced when the robot behaved socially. Similarly, dogs spent more time gazing at the head of the robot experimenter when the situation was social. Dogs achieved a significantly lower level of performance (finding the hidden food) with the pointing robot than with the pointing human; however, separate analysis of the robot sessions suggested that gestures of the socially behaving robot were easier for the dogs to comprehend than gestures of the asocially behaving robot. Thus, the level of sociality shown by the robot was not enough to elicit the same set of social behaviours from the dogs as was possible with humans, although sociality had a positive effect on dog-robot interactions.

Evolutionary approach to communication between humans and dogs.

Dogs and humans have been sharing a common environment for a long time. Some aspects of their social interaction are described as communication in which members of both species influence each other's behaviour by special behaviour signals. Recent research is aimed at providing an evolutionary account for the emergence of communicative interactions between dogs and people. The present review summarizes how carefully applied experimental methods can be utilised to answer such research questions, in order to separate different processes that may underlie the mental abilities in dogs.

Molecular and behavioral analysis of the intron 2 repeat polymorphism in the canine dopamine D4 receptor gene.

Genetic polymorphisms in the human dopamine D4 receptor (DRD4) gene, especially the exon 3 variable number of tandem repeats (VNTR), have been related to several psychiatric disorders and personality traits. A homologous exon 3 VNTR has been described in dogs, and we previously showed an association between the DRD4 exon 3 polymorphism and activity/impulsivity trait in German shepherds. In this study, we present a detailed analysis of the intron 2 VNTR of the DRD4 gene. A short and a long form of the intronic variation were identified in 678 unrelated dogs from five breeds and in 22 wolves. For molecular analysis, the intron 2 region was cloned into a promoterless luciferase reporter vector that led to an elevation in transcriptional activity. Moreover, an allelic difference in promoter activity was detected, and a repressive effect of the long allele was observed. Behavioral analysis of 96 unrelated German shepherds showed a significant association between the social impulsivity endophenotype of the Greeting Test and both the exonic (P = 0.002) and the intronic (P = 0.003) VNTRs of the DRD4 gene. Moreover, an additive effect of the two polymorphisms was also shown (Spearman's rho = 0.356, P = 0.0004). In conclusion, these results give further support to our previous findings that the DRD4 gene is associated with dog behavior. We also present molecular evidence for the functional role of the intron 2 VNTR in the canine DRD4 gene.

Association of polymorphisms in the dopamine D4 receptor gene and the activity-impulsivity endophenotype in dogs.

A variable number of tandem repeats (VNTR) polymorphism in exon 3 of the human dopamine D4 receptor gene (DRD4) has been associated with attention deficit hyperactivity disorder (ADHD). Rodents possess no analogous repeat sequence, whereas a similar tandem repeat polymorphism of the DRD4 gene was identified in dogs, horses and chimpanzees. Here, we present a genetic association study of the DRD4 VNTR and the activity-impulsivity dimension of the recently validated dog-ADHD Rating Scale. To avoid false positives arising from population stratification, a single breed of dogs (German shepherd) was studied. Two DRD4 alleles (referred to as 2 and 3a) were detected in this breed, and genotype frequencies were in Hardy-Weinberg equilibrium. For modelling distinct environmental conditions, 'pet' and 'police' German shepherds were characterized. Police German shepherds possessing at least one 3a allele showed significantly higher scores in the activity-impulsivity dimension of the dog-ADHD Rating Scale than dogs without this allele (P = 0.0180). This difference was not significant in pet German shepherds. To the best of our knowledge, this is the first report of an association between a candidate gene and a behaviour trait in dogs, and it reinforces the functional role of DRD4 exon 3 polymorphism.

Behavioural comparison of human-animal (dog) and human-robot (AIBO) interactions.

The behavioural analysis of human-robot interactions can help in developing socially interactive robots. The current study analyzes human-robot interaction with Theme software and the corresponding pattern detection algorithm. The method is based on the analysis of the temporal structure of the interactions by detecting T-patterns in the behaviour. We have compared humans' (children and adults) play behaviour interacting either with an AIBO or a living dog puppy. The analysis based on measuring latencies and frequencies of behavioural units suggested limited differences, e.g. the latency of humans touching the dog/AIBO was similar. In addition other differences could be accounted for by the limited abilities of the robot to interact with objects. Although the number of interactive T-patterns did not significantly differ among the groups but the partner's type (whether humans were playing with dog or AIBO) had a significant effect on the structure of the patterns. Both children and adults terminated T-patterns more frequently when playing with AIBO than when playing with the dog puppy, which suggest that the robot has a limited ability to engage in temporally structured behavioural interactions with humans. As other human studies suggest that the temporal complexity of the interaction is good measure of the partner's attitude, we suggest that more attention should be paid in the future to the robots' ability to engage in cooperative interaction with humans.

A nonverbal test of knowledge attribution: a comparative study on dogs and children.

The sensitivity of eleven pet dogs and eleven 2.5-year-old children to others' past perceptual access was tested for object-specificity in a playful, nonverbal task in which a human Helper's knowledge state regarding the whereabouts of a hidden toy and a stick (a tool necessary for getting the out-of-reach toy) was systematically manipulated. In the four experimental conditions the Helper either participated or was absent during hiding of the toy and the stick and therefore she knew the place(s) of (1) both the toy and the stick, (2) only the toy, (3) only the stick or (4) neither of them. The subjects observed the hiding processes, but they could not reach the objects, so they had to involve the Helper to retrieve the toy. The dogs were more inclined to signal the place of the toy in each condition and indicated the location of the stick only sporadically. However the children signalled both the location of the toy and that of the stick in those situations when the Helper had similar knowledge regarding the whereabouts of them (i.e. knew or ignored both of them), and in those conditions in which the Helper was ignorant of the whereabouts of only one object the children indicated the place of this object more often than that of the known one. At the same time however, both dogs and children signalled the place of the toy more frequently if the Helper had been absent during toy-hiding compared to those conditions when she had participated in the hiding. Although this behaviour appears to correspond with the Helper's knowledge state, even the subtle distinction made by the children can be interpreted without a casual understanding of knowledge-formation in others.

Detection of temporal patterns in dog-human interaction.

A new time structure model and pattern detection procedures developed by (Magnusson, M.S., 1996. Hidden real-time patterns in intra- and inter-individual behaviour description and detection. Eur. J. Psychol. Assess. 12, 112-123; Magnusson, M.S., 2000. Discovering hidden time patterns in behaviour: T-patterns and their detection. Behav. Res. Methods, Instrum. Comput. 32, 93-110) enables us to detect complex temporal patterns in behaviour. This method has been used successfully in studying human and neuronal interactions (Anolli, L., Duncan, S. Magnusson, M.S., Riva G. (Eds.), 2005. The Hidden Structure of Interaction, IOS Press, Amsterdam). We assume that similarly to interactions between humans, cooperative and communicative interaction between dogs and humans also consist of patterns in time. We coded and analyzed a cooperative situation when the owner instructs the dog to help build a tower and complete the task. In this situation, a cooperative interaction developed spontaneously, and occurrences of hidden time patterns in behaviour can be expected. We have found such complex temporal patterns (T-patterns) in each pair during the task that cannot be detected by "standard" behaviour analysis. During cooperative interactions the dogs' and humans' behaviour becomes organized into interactive temporal patterns and that dog-human interaction is much more regular than yet has been thought. We have found that communicative behaviour units and action units can be detected in the same T-pattern during cooperative interactions. Comparing the T-patterns detected in the dog-human dyads, we have found a typical sequence emerging during the task, which was the outline of the successfully completed task. Such temporal patterns were conspicuously missing from the "randomized data" that gives additional support to the claim that interactive T-patterns do not occur by chance or arbitrarily but play a functional role during the task.

Does dog-human attachment affect their inter-specific cooperation?

Leading a blind or blindfolded person is a complex cooperative task influenced by many factors. The aim of this study was to determine if quality of attachment affects the performance of dog and owner dyads showed on an Obstacle Course. Modified Ainsworth's Strange Situation Test was used for assessing attachment quality. Only one dimension of the attachment, the 'anxiety' factor was found to correlate with behavioural measures of the Obstacle Course (e.g. number of mistakes, initialisation index that reflects which participant initiates more actions in a dyad). We found significant differences of performance between the three groups of dog-owner pairs (pet dog, guide dog and police dog dyads), but we could not show significant differences in the 'attachment' factor among these groups. We concluded that it is not the attachment type that causes the main differences in the leading behaviour of our three study groups. Dogs have an innate ability for cooperation with humans that was enhanced by selective breeding during domestication and this basic ability can be modified by training but seem to be less affected by the relationship with the owner.

The effects of the visual environment on responses to colour by domestic chicks.

It is well known that development of vision is affected by experience, but there are few studies of environmental effects on colour vision. Natural scenes contain predominantly a restricted range of reflectance spectra, so such effects might be important, perhaps biasing visual mechanisms towards common colours. We investigated how the visual environment affects colour preferences of domestic chicks ( Gallus gallus), by training week-old birds to select small food containers distinguished from an achromatic alternative either by an orange or by a greenish-blue colour. Chicks that had been raised in control conditions, with long-wavelength-dominated reflectance spectra, responded more readily to orange than to blue. This was not due to avoidance of blue, as increasing saturation enhanced the chicks' preference for the same hue. The advantage of orange was, however, reduced or abolished for chicks raised in an environment dominated by blue objects. This indicates that responses to coloured food are affected by experience of non-food objects. If colours of ordinary objects in the environment do influence responses to specialised visual signals this might help explain why biological signals directed at birds are often coloured yellow, orange or red; long-wavelength-dominated spectra being more prevalent than short-wavelength-dominated spectra.

Comprehension of human communicative signs in pet dogs (Canis familiaris).

On the basis of a study by D. J. Povinelli, D. T. Bierschwale, and C. G. Cech (1999), the performance of family dogs (Canis familiaris) was examined in a 2-way food choice task in which 4 types of directional cues were given by the experimenter: pointing and gazing, head-nodding ("at target"), head turning above the correct container ("above target"), and glancing only ("eyes only"). The results showed that the performance of the dogs resembled more closely that of the children in D. J. Povinelli et al.'s study, in contrast to the chimpanzees' performance in the same study. It seems that dogs, like children, interpret the test situation as being a form of communication. The hypothesis is that this similarity is attributable to the social experience and acquired social routines in dogs because they spend more time in close contact with humans than apes do, and as a result dogs are probably more experienced in the recognition of human gestures.

Role of right hemifield in visual control of approach to target in zebrafish.

When a zebrafish has to choose between two identical stimuli (e.g. a conditioned stimulus, CS, for food reward), it tends to respond to the one on its right. Errors are more numerous when reinforced for taking the one on the left rather than the one on the right. When trained to a single medial stimulus, and presented in non-reinforced probe trials with a pair of identical stimuli, the one on the right is chosen. Use by zebrafish of right eye (RE), viewing to control a planned motor response, extends from objects that are to be bitten to a choice of one of two routes. When the CS is visible behind a barrier of vertical bars, so that it can be approached around either end, it is the right end that is chosen. Standing motor bias independent of the nature of the task can be excluded. Other vertebrates show RE control of response. Toads are more likely to take food seen with the RE. The domestic chick uses the RE in visual control of approach to an object that has to be manipulated with the bill. RE control of use of the mouth in a fish shows that that this is an earlier condition than lateralised control of bilateral effectors like hands.

Right eye use associated with decision to bite in zebrafish.

Cerebral lateralisation is revealed in the zebrafish by preferential eye use, which differs according to the visual stimulus that is being fixated. Past findings [Bisazza A, Pignatti R, Vallortigara G. Behav. Brain Res. 1997b;89:237-242; Miklósi A, Andrew RJ, Savage, H. Physiol. Behav. 1998;63:127 135] suggest that the right eye is used when the stimulus (or scene) is such as to require a careful period of examination in order to decide on a response. The left eye is used when the fish has to check whether an identical stimulus has been seen before. We here show that the same association of right eye use with decision to respond holds for biting at small targets (coloured or black and white beads). Biting and right eye use were both high at the first presentation of both types of bead, and fell together over two further trials with the same type of bead. At the fourth trial the appearance of the bead was changed. A change in colour caused both right eye use and biting to return, whereas a change in orientation of the black stripe on the black and white bead had no effect on either (and seemed to be largely ignored). In the case of the coloured beads, habituation of biting was accompanied by continued interest, shown by increased binocular fixation. The reduction in reliance on right eye viewing thus represents a change in the strategy of analysis rather than coming to ignore the stimulus. It would allow a greater involvement of the left eye system.

The ethological analysis of imitation.

Theorists and experimental researchers have long debated whether animals are able to imitate. A variety of definitions of imitation have been proposed to describe this complex form of social learning. Experimental research on imitation has often been hampered by either a too loose 'anthropomorphic' approach or by too narrow 'behaviourist' definitions. At present neither associative nor cognitive theories are able to offer an exhaustive explanation of imitation in animals. An ethological approach to imitation offers a different perspective. By integrating questions on function, mechanism, development and evolution one can identify possible directions for future research. At present, however, we are still far from developing a comprehensive theory of imitation. A functional approach to imitation shows that, despite some evidence for imitative learning in food processing in apes, such learning has not been shown to be involved in the social transmission of either tool-use skills or communicative signals. Recently developed procedures offer possible ways of clarifying the role of imitation in tool use and visual communication. The role of imitation in explorative play in apes is also investigated and the available data suggest that copying during play might represent a behavioural homologue of human imitation. It is proposed that the ability to copy the behaviour of a companion is under a strong genetic influence in many social species. Many important factors have not been examined experimentally, e.g. the effect of the demonstrator, the influence of attention and memory and the ability to generalize. The potential importance of reinforcement raises the possibility that copying abilities serving divergent functions might be partly under the control of different mechanisms.