Dogs’ undeniable loyalty to humans has allowed them to carve out a unique niche in our society, quite unlike the status of any other species. Once predominantly utilized as hunting companions and guardians, dogs are now ubiquitous in human life, offering faithful companionship and service. Thanks to their eagerness to cooperate with humans and unquestioning dependability, the ways in which dogs enhance our lives are ever-increasing; in addition to pet ownership, dogs are used for guiding the blind, providing physical and emotional support, detecting explosives and contraband, and much more.
Our ability to rely on dogs’ unwavering loyalty stems partly from their genetic history. During the process of domestication, selection pressures favoring friendliness towards humans may have bestowed survival advantages by way of access to human provisions. Recent accounts point to the existence of a social and emotional cooperative relationship between early humans and primitive dogs as early as the Paleolithic period. More recently, humans artificially selected for specific traits, enhancing different aspects of the dog-human relationship and creating many of the breeds we see today. In addition to genetic predispositions that have enabled dogs to flourish in an anthropocentric world, dogs readily learn to modify their behavior in order successfully cohabitate with us.
Decades of research have illustrated the depths of the dog-human bond. Dogs can respond to a range of human social signals, read our emotional and attentional states, and are thought capable of experiencing empathy towards humans. Cross-species comparisons suggest that dogs’ “human-like” social cognition may be unique in the animal kingdom, likely a product of both domestication and enculturation. But have we instilled in them a devotion so strong that we have made dogs loyal to a fault? Studies have shown that dogs’ willingness to respond to human signals is so strong that they will readily follow misleading cues despite conflicting information. The extent to which dogs will faithfully respond to human behavior in the face of contradictory, ambiguous, or irrelevant information and what it tells us about the uniqueness of canine and human cognition was addressed using diverse approaches by three different papers in the special issue on canine cognition in Learning & Behavior.
Perhaps the most extensively studied topic in canine social cognition is that of dogs’ responsiveness to human pointing. In light of evidence that dogs are susceptible to ostensibly misleading human cues, such as pointing to an empty container instead of an obviously baited container, Dwyer and Cole asked the question of whether dogs could learn to eschew such deception. That is, would dogs continue to respond to clearly incorrect information, as has been previously demonstrated, or can they learn to eventually abandon trust of a deceitful informant?
The researchers used the classic object-choice task paradigm, commonly used to assess point-following behavior in dogs, in which a human informant points to one of two containers in order to indicate the location of a hidden reward. Modifying the task so as to confront dogs with “deceitful” cues, two different types of trials were used. On 20 cooperator trials, the experimenter stood behind the container baited with a food treat and pointed directly to the container. If the dog selected the signaled container by approaching it, the food reward was offered. On 20 deceiver trials, the procedure was identical except that the container pointed to by the experimenter (a different person than the experimenter used in cooperator trials) was empty. Moreover, the containers were transparent so that the contents of the container (or lack thereof) were clearly visible.
Consistent with previous studies, Dwyer and Cole found that dogs had difficulty ignoring the misleading cues of the deceiver. This pattern held even with modifications of their study which included the use of two different experimenters playing the roles of the cooperator and deceiver in successive trials, and the use of transparent containers. Thus, even though the trustworthy and untrustworthy experimenters should have been easily discriminable, and the deceiver’s signaled container were clearly empty, dogs never completely learned to abstain from following the deceptive points (shown in the figure below).
It remains to be seen whether additional trials would eventually completely extinguish dogs’ tendency to follow the deceiver’s point. Nevertheless, the authors suggest that dogs’ strong willingness to follow the cues of a human, which persisted even after several opportunities to learn that the deceiver was in fact untrustworthy, reflects a genetic predisposition resulting from selection for traits that enhanced attention towards humans.
Dwyer and Cole question the survival value of such blind devotion to humans. However, it is also possible that dogs interpret the gesture provided by the human as a command, following the deceiver’s point not out of blind devotion but out of obedience. In this view, dogs’ tendency to follow the demands of a human, even if in conflict with the dogs’ own inclinations, makes sense. In an environment where the consequences of dogs’ behavior are largely dictated by humans, acting against natural instincts in deference to a perceived request of a human may be adaptive after all.
This point was also raised in another article by Johnston, Huang, and Santos, who further explored dogs’ tendency to defer to communicative gestures provided by humans. Using a slightly different methodology, Johnston and colleagues employed the Guesser-Knower paradigm which presents dogs with two conflicting informants simultaneously: the ‘Knower’, who viewed the baiting of the container and therefore can be trusted to know its contents, and the ‘Guesser’, who did not witness the baiting and therefore should not be relied on for information. This setup eliminates the need for dogs to disobey the command of a single informant, and instead presents a choice between two.
Building upon previous research showing that dogs preferentially follow a Knower’s point over a Guesser, and that human children struggle to override a Guesser’s communicative cues (i.e., pointing) but not non-communicative cues (e.g., placement of a marker), Johnston and colleagues aimed to determine whether dogs show a similar bias as children. That is, if the communicative nature of the cue is as salient to dogs as they appear to be for children, dogs should show a greater difficulty to override the Guesser’s incorrect cue in the communicative condition than in the non-communicative condition.
Across two experiments, Johnston and colleagues manipulated two aspects of the study: the dog’s view of the baiting (visible or hidden to the dog), and the non-communicative cue used (marker placement or grasping). In all conditions the Knower indicated the baited container, and the Guesser indicated the empty container. When the baiting process was visible and relying on the informants’ cues was not necessary, dogs were able to correctly choose the baited container, as shown below in the ‘visible’ condition. However, when the baiting was invisible and dogs had to rely on the informants’ signals, dogs were more likely to follow the Knower’s pointing cue compared to the non-communicative marker cue, but equally likely to follow her communicative and non-communicative goal-directed cue (i.e., grasping).
Taken together, Johnston and colleagues concluded that the Guesser’s communicative cues did not interfere with dogs’ ability to rely on the Knower and that dogs do not defer to communicative actions when lacking the direct information necessary to make an informed choice. Thus, although effects were marginal, the authors suggest that dogs do not possess a human-like bias towards communicative cues in the way that children do. Placing these findings in an evolutionary context, Johnson and colleagues suggest that although domestication may have shaped canine social cognition in ways that enhance dog-human interactions, certain unique mechanisms (e.g., bias towards communicative actions) may have supported the evolution of complex human culture.
Social learning, or the ability to learn by observing or imitating the actions of another individual, is thought to be critical to the development of culture. While this type of learning has been observed in many social species, humans are thought to be unique in their tendency to copy inefficient or irrelevant actions, known as overimitation. Seemingly maladaptive, overimitation may occur because children perceive certain actions as norms that must be followed, and may be useful in promoting affiliation and learning. Evidence of overimitation in dogs may be suggestive of parallel mechanisms, enhancing the dog-human bond (note that, while studies have shown evidence of conspecific social learning in dogs, here we focus on dog-human imitation). Indeed, similar to dogs’ tendency to follow misleading human cues, dogs appear to be the only species tested thus far that will faithfully copy irrelevant actions of a human.
In order to further explore the social mechanisms of “blind” copying in dogs, Huber, Popovová, Riener, Salobir, and Cimarelli presented groups of dogs with different sequences of actions performed by their owner. The actions consisted of a causally irrelevant action (touching colored dots on a wall) and a relevant action necessary to achieve a goal (sliding a trap door to reveal a treat). To tease apart the effects of viewing relevant or irrelevant actions on overimitation tendencies, each group viewed a different combination of actions. Two groups viewed only one action, either the relevant action or the irrelevant action. Two other groups viewed both actions but in different orders, either the irrelevant action followed by the relevant action, or vice versa.
About half of the dogs copied the irrelevant action of touching the colored dots after viewing their caregiver do so, and this tendency was observed whether dogs saw the action alone or in combination with the relevant action. Thus, observing the functionally necessary action did not reduce dogs’ tendency to imitate the unnecessary action. Moreover, perfect imitation of touching the dots in the same order as the demonstrator and then sliding the door in the same direction was only observed in dogs that had observed these actions. Overall, there was a strong relationship between observing a particular action and then performing the action.
Taken together, despite a general low level of true imitation in the dogs tested, Huber and colleagues suggest that these findings are evidence of over-imitation in dogs‒previously thought to be uniquely human. Moreover, the marginal effect is magnified when compared to previous studies with apes, in which not one individual exhibited over-imitation. In this case, dogs perform similarly to children and their behavior suggests that over-imitation has underlying affiliative and other social motivations.
The general pattern emerging from the three papers discussed here reveals the unique ways in which domestication and enculturation have shaped canine cognition. It seems clear that certain behavioral tendencies seen in dogs but not in other species are the product of human selection (both genetic and behavioral), as well as mechanisms used by dogs to enhance the dog-human bond. And while we see increasing evidence for ‘human-like’ cognition in dogs, certain aspects that remain apparently exclusive to humans are likely critical for sustaining uniquely complex human culture.
So what is the take home message here? While at face value dogs’ eager willingness to follow deceptive, contradictory, or ineffective behavior from humans may be interpreted as the antiquated ‘dumb dog’ stereotype, it is important to remember the anthropocentric world in which dogs operate. Overriding their natural instincts in order to assuage their human partners, which in turn has clear advantages, is more likely a sign of just how clever dogs are.