Dogs: Psychology and Communication

The Communicative Social Skills of Man’s Best Friend
In a rhetorical sense, dogs are no strangers to humans. This is quite obvious, as man and dog have shared a long and close history with each other. Dogs were first domesticated 15,000 years ago from the gray wolf (Scott & Fuller, 1974). Although the domestication of dogs has not been formally documented in the history books of man, there is reliable empirical data to support the origin of the domestic dog from wolves. Mitochondrial DNA sequence variations from hundreds of domestic dogs were compared and the data resulted in a monophyletic group of dogs nested within a clade of gray wolves. This suggests that there is an origin of dogs resulting from a single gene pool (Savolainen, Luo, & Leitner, 2002). Man has shaped the evolution of the domestic dog via artificial selection, resulting in vast variations and similarities among dogs. Because all dogs share a common ancestor, there are bound to be some similarities in all domestic dogs. At the same time, there are also bound to be many differences among dog breeds as well. In fact, there are over 450 different breeds of dogs (Scott et al. 1974). Different breeds of dogs exhibit phenotypic aesthetic differences, behavioral differences, and even cognitive differences. Nonetheless, there are still some characteristics that were selected for in most dogs. Such a characteristic is communication with humans. Undoubtedly wolves, dogs, and other species such as orangutans show communication to some extent. Communication is vital for the survival of the individual and the species, especially if they are social species living in groups. Without the ability to communicate, the animals would not be able to form social groups, hunting groups and/or other activities where communication is necessary. Communication is a crucial trait for dogs specifically because of the close proximity to which humans and dogs live. Dogs must not only be able to communicate with each other, but also the humans. Without the ability of interspecies communication, dogs are at a severe disadvantage that may inhibit their ability to survive in a domestic setting. Through the process of domestication, man selected for special skills in dogs to comprehend human communicative behaviors. Dog’s exceptional ability to follow human-given cues is a result of the domestication of dogs and the artificial selection of communicative traits. This evolved interspecies communication supports the notion, in a literal sense, that dogs are no strangers to human. Humans controlled the evolution of dogs, shaping them to be exactly what we want them to be. As a result, man created his best friend.
To start the discussion, we will first look at the modes of communication of dogs, starting off with barking. The action of barking is very interesting to researchers because barking is found readily in dogs and rarely in wolves (Scott & Fuller, 1965). This behavioral difference has led researchers to believe that barking must be a behavioral trait that arose as a result of the domestication of dogs. There are many hypotheses for the prevalence of barking in domestic dogs. One hypothesis suggests that humans may have directly selected for barking, whereas another hypothesis suggests that humans may have indirectly selected for barking by selecting for other traits such as tameness (Coppinger & Feinstein, 1991). However, not all dogs readily bark. Barking was selected for in some dog breeds and was selected against in other breeds. For example, humans have selected against barking in hunting dogs, whereas barking has been selected for in guard dogs (Yin, 2002). In the latter case, barking is imperative because it the primary mode in which a dog can communicate with humans, by bringing our attention to a certain stimuli such as an intruder. The artificial selection seen in dogs represents ultimate causes for improved dog interspecies communication and an ultimate cause for increased or decreased barking in specific dog breeds. Another hypothesis for the prevalence of barking suggests that certain changes in environments may have increased barking. This represents a proximal cause for the increased barking. The urban setting that many dogs live in may contribute to increase barking prevalence because dogs are now confined to smaller territories that are often invaded by intruders. For example, if a mailman approaches a house, a dog may bark at the intruder to defend its “territory.” This behavior is subsequently reinforced when the mailman leaves, as the barking was successful in deterring the intruder. Ultimate causes represent the genetic influences that affect barking, whereas proximate causes represent more of the social environmental influences that will affect barking. Because of the domestication of dogs, dogs have been faced with both ultimate and proximate causes that may have affected barking prevalence. For example, in the case of the hunting dog, the lack of barking may have been influenced by both a proximate cause, as their owner will punish hunting dogs that do not remain silent, and an ultimate cause, as humans selectively breed quiet dogs to be hunting dogs.
As mentioned above, domestic dogs often rely on humans for their survival and thus dogs may use barking as a way to get the human’s attention. This behavior is reinforced as the human subsequently feeds the dog or takes the dog out to the grass (Beaver, 1999). Some researchers have proposed the notion that barking may also be used as honest signaling to demonstrate their strength. It is sometimes observed that dogs will engage in “barking matches” until one dog or groups of dogs retreat. By using honest signaling, dogs can avoid a potentially dangerous fight (Yin, 2002). This, however, does not seem like a probable explanation for barking because it assumes a situation in which dogs are living independent of humans. Domestic dogs do not need to engage in barking matches in order to determine who is the stronger dog. There is no advantage to such an occurrence because this will not increase the fitness of the dog. Domestic dogs are taken care of by humans, and therefore their fitness is determined by humans, rather than competition with other dogs, as would be seen in the natural-wild environment. In a way, dogs are exempt from the natural selection, and mainly susceptible to artificial selection by humans.
Clearly, barking is observed in many different contexts and there is evidence to support the fact that the acoustic structure of barks does vary predictably with the different contexts. Thus because barks are context-specific, barking must serve a function of some kind (Yin, 2002). This does not suggest that dogs have a language, but rather it suggests that dogs are able to communicate emotions and desires. There are warning barks, alarm barks, playful barks, and need barks. Additionally, there are other utterances that dogs use, all which are used in different contexts and have different significances. Growls, for example, can be used to express aggression or even a desire to play. Whimpering may be used to signal pain, and whines may be used to signal a desire for something, such as food or attention, and/or anxiety. There is no doubt that dogs can make and use various auditory utterances and these different utterances have different semantic significances. The same utterance may vary in semantics depending on the context, indicating that dog utterances are not simple, black-and-white mechanisms of communication. They are very advanced and not well understood by humans (Coppinger & Feinstein, 1991).
Thus far we have talked about the modes of communication in dogs, but now we will focus more on the ultimate causes that have resulted in the cognitive ability for dogs to understand human social communicative signals. From an evolutionary point-of-view, it appears that dog’s social communicative skills must be determined on a genetic level. However, there are some animal behaviorists who suggest that dog’s social communicative skills are the direct result of human exposure and the dog’s success at understanding human-given cues is simply something that is learned, not genetically predisposed. If this is the case, then a newly born puppy should not exhibit social communicative skills. Only with further experience and exposure to humans should such skills emerge. Riedel and colleagues (2007) present a study in which they examine the early ontogeny of human-dog communication. To do this, Riedel and colleagues (2007) studied the ability of puppies/dogs of varying age classes to follow human-given communicative cues to locate hidden food. The age of the puppies is key to this experiment because the youngest puppies have no prior experience with humans. The study found that dogs, regardless of age, were equally successful at using human-given communicative cues to locate the hidden food. Because there were no major differences between the different age classes in the study, we can rule out the possibility that dog’s social communicative skills are the result of solely human exposure. Unfortunately this study does not have the foundation to state how such communicative skills emerged in dogs. One hypothesis states that humans directly selected (via artificial selection) for communicative skills in dogs. Over generations of artificial selection, the domestic dog became genetically predisposed to understand human-given cues (Coppinger & Coppinger 2002). Another hypothesis states that communicative skills evolved in dogs as an indirect result of selection against other traits, such as aggression and fear (Hare et al. 2005). A third hypothesis can be made that states that such communicative skills evolved as a result of both direct selection for the communicative skills and selection against aggression and fear (Reidel et al. 2007). The third hypothesis seems most parsimonious, as there is unlikely to be solely one evolutionary factor driving the entire evolution of communication in dogs.
We have just discussed how dog’s success at understanding human-given cues was not merely a feat of simple learning; the ability to use human-given cues was influenced on a genetic level. In 1994, Call and Tomasello (1994) conducted a fascinating experiment to understand the influence of human exposure to acquire the skill to understand human cues. Specifically, the researchers used orangutans for the experiment. Orangutans were used because they are one of the closest primate species to humans. This study shed light on the learning hypothesis presented earlier. Orangutans have not been genetically predisposed to understand human-given cues and therefore their success at human-given cue tests will yield much information on the ability to learn human communicative signals without the influence of domestication. The experiment investigated orangutan’s comprehension of the significance of a human point and how it helped to locate food. In all cases, the researchers found that uncultured orangutans, those with previous exposure to humans, performed significantly better than captive orangutans, those who taken from the wild and had no previous exposure to humans (Call et al. 1994). This study suggests that learning does play a role in one’s ability to understand human-given cues, although it not the only factor. Thus, both learning and genetics play an influential role in the communicative social skills of domestic dogs, which is consistent with the view that there are both proximate and ultimate causes for the evolution of communication in dogs.
A similar experiment was conducted to analyze comprehension of human communicative signs in domestic dogs. The experiment used four types of directional cues that were given by the experimenter. The cues included pointing and gazing, head nodding (“at target”), and head turning above the correct container (“above target”) and glancing only (“eyes only”). The experimenter would use a communicative cue to indicate the presence of hidden food, which was under a container. Only one of the containers contained food, which was the reward for selecting the correct container. The results indicate that dogs were able to use all communicative signals by the experimenter except for the pointing cue (Soproni, Miklósi, Topál, & Csányi, 2001). It is likely that such results arise due to the fact that pet dogs live in a human household and must have had more previous experiences with head nodding, head turning, and eye glancing than pointing. Children, similarly, do not register the gesture of a point as a communicative signal indicating the presence of hidden food, the reward. Both dogs and children are less exposed to pointing as a communicative signal in an average human household, and this lack of exposure may explain why domestic dogs and children performed similarly. Children and dogs both grow up in similar environments, which may have proximate influences on the ontogeny of the individual. Additionally, pointing cues are not readily observed in a nature and therefore it is not as easily learned as a cue. However, studies show that dogs can be trained to learn pointing as a cue, although it is much more difficult than other gestures (Miklósi et al. 1998). Communicative cues, such as head turning are readily observed in nature and therefore this gesture is learned easily.
Thus far, it can be seen that dogs and children have more similar affinities to learn communicative cues than chimpanzees. Chimpanzees have less experience with humans than both children and dogs and this difference in experience may explain the differences in human-given cue performance. Another hypothesis is that via domestication, dogs have been selectively sensitized to human communicative gestures (Povinelli et al. 1999). It is likely that dog’s sensitivity to human communicative gestures is the result of domestication and experience and exposure to humans. Again, we observe both proximate and ultimate explanations for the improved social communicative skills in domestic dogs.
The next step in understanding social cognition in dogs with respect to communication is to test and compare dogs with other animals and observe the differences. Specifically, we want to compare dogs with wolves, their ancestors, and chimpanzees, primates closely related to humans. Because dogs evolved from wolves, we would expect similarities in their performance. However, because of the many evolutionary selective pressures on dogs, we should observe some differences as well. In the study conducted by Hare and Colleagues (2002), the researchers used a procedure very similar to that of Call and Tomasello (1994). In the first part of the experiment, Hare and Colleagues (2002) tested dogs and chimpanzees and their ability to correctly choose the baited container. Dogs performed significantly better than the chimpanzees. Figure 1 demonstrates this difference visually.

Figure 1: This graph represents the mean number of correct choices by dogs and chimpanzees when given a social communicative cue (Hare et al. 2002).
The next part of the experiment tested dogs and wolves and their ability to use different types of cues to find the hidden food. The types of cues included (1) Gaze + Point + Tap cue (GPT), (2) Gaze + Point cue (GP), (3) Point cue (P), and (4) control group (no cue given). Dogs performed significantly better than wolves when given a communicative cues by a human. When no cue was given, as seen in the control group, both dogs and wolves performed at chance. Figure 2 demonstrates this difference visually.

Figure 2: This graph represents the mean number of correct choices in each of the 3 experimental conditions and 1 control condition. It is easy to see how dogs scored significantly higher than wolves for all 3 experimental conditions and there was no significant difference in the control condition (Hare et al. 2002). The results of this experiment make it clear that dogs are exceptional when it comes to using human-given cues. Dogs scored higher than both chimpanzees and wolves. Because dogs performed significantly better than the ancestral wolves, it is likely that one thing that differentiates dogs from their ancestors is dog’s social communicative skills with humans. These results provide strong evidence for the domestication of dogs, and through the process of domestication, dogs’ social communicative skills with humans have improved. We have discovered that dogs have a profound ability read human-give cues. But we have still yet to determine the exact method by which socialization occurs. To specify, socialization with humans indicates the ability to accept humans as social companions and as a result, the ability to comprehend human-given communicative cues. The notion of a critical period plays an important role in many animal species and explicitly the ontogeny of a given species. A critical period is defined broadly as a period in an early stage in an organism’s life at which the organism becomes more sensitive to certain stimuli. As a result of the exposure to the stimuli, the organism will develop is a certain way (Freedman, King, & Eliot, 1961). Critical periods are observed in numerous species and are critical for their ontogeny. For example, in songbirds, it is often seen that there is a critical period in which song acquisition must take place. If song acquisition does not take place during the critical period, that individual songbird may lack the ability to learn the song. Similarly, dogs and wolves also have a critical period in which socialization with humans must take place. If the dog or wolf does not socialize within the critical period, the dog or wolf may never become socialized with humans and may lack the skills to comprehend human-given communicative cues. Domestic dogs may start socialization with humans as late as 16 weeks. Wolves, on the other hand, have a much shorter critical period, ranging between 10-14 days (Coppinger et al. 2001). Clearly, the domestic dog has a much lengthier critical period than their wolf ancestors. Such differences in the critical period may be the result of domestication, as the process of domestication directly or indirectly selected for longer critical periods in dogs. A longer critical period can increase an individual’s fitness because it increases the probability that that individual will socialize with humans and will survive. A dog that is unable to socialize may have difficulty living in a human household and may be unable to communicate with humans or vice versa. This can potentially affect the survival of the individual. Thus the lengthier critical period is advantageous because it increases the likelihood of socialization and survival.
Perhaps dogs are not given enough credit for their cognitive abilities. For example, Kaminski and colleagues (2004) present a case in which a dog is able to fast map, which is a process in which a novel concept can be learned based off a single exposure to certain information (Swingley, 2010). When Rico is told the name of an object, Rico is readily able to identify the objects and bring them to his owner. This suggests that Rico has made the association that objects can have names. To test fast mapping directly, researchers placed a novel item within a group of familiar objects and asked Rico to bring the novel item. Rico hears an unfamiliar name and uses the process of elimination to identify the new name with the novel item. Thus he was able to link the novel word to a novel item based on exclusion learning. Additionally, Rico was able to remember the name-item associations even four weeks after being introduced to the novel item. This retrieval rate performance is comparable to three-year-old toddlers (Kaminski, Call, & Fisher, 2004). It is interesting how dog’s performance was comparable to that of a three-year-old toddler in both this fast mapping test and the test mentioned early analyzing the comprehension of human communicative signs in domestic dogs by Soproni et al. (2002). Perhaps this is a result of the similar ontogeny of domestic dogs and human toddlers due to the similar environments in which they are raised. This would also suggest proximal causes for fast mapping, but this is not to say that ultimate causes are not influential. The evolution of fast mapping as a result of artificial selection would yield ultimate causes for the ability to fast map. However, there simply needs to be more research in this topic to fully understand how dogs evolved the ability to fast map. Nonetheless, dogs have rather complex linguistic skills that deserve acknowledgement.
The communicative social skills of dogs have many advantages to humans. First, and quite obviously, dog’s social skills help humans communicate with dogs, and second, dogs are able to communicate with humans. This symbiotic relationship can even have advantages to help the disabled. For example, dogs can be used to help deaf people. Essentially, these dogs live alongside a deaf person and help alert their masters to certain household sounds and possible dangers. These dogs will alert their masters when the doorbell rings, the phone rings, a smoke detector sounds, and plenty more. The dogs alert their masters by touching the master, thus making the deaf person more aware of their surroundings (About Hearing Dogs, n.d.). This is just one example of how dogs can help humans with day-to-day activities. Dogs help humans in various other ways too, such as detecting a scent or herding sheep.
In retrospect, we see that communication in dogs is influenced by artificial selection and human-exposure, presenting both ultimate and proximal influences on dog communication, respectively. These two factors have shaped dog’s cognition, allowing them to comprehend human-given cues and live within a domestic setting. Dogs have a predisposed advantage at human socialization and as a result, it is not hard to see why dogs are man’s best friends. Man created dogs to be exactly what man wants. Essentially, man created the ultimate friend, companion, and helper. Much of the literature in this field of study is focused on providing data to show that dogs can produce context-specific barks, can use human-given cues to locate something, and can fast map. However, the literature does not shed light on why such traits exist. The literature points to artificial selection by humans and human-exposure as the cause of the trait differences seen in dogs, but correlation does not imply causation. The simple fact that more domesticated dogs are correlated with better scores on the human-give cue tests does not imply that domestication caused better test performance. Alternate explanations for the mechanisms by which these traits arose should be a focus on future research on dogs. Dogs have proven exceptional abilities that are beyond belief. Now it is time to understand why, from both a psychological and physiological point-of-view. This is a very fascinating area of research that hopefully continues to grow and we can learn more about man’s best friends and why they are no strangers to man. We are essentially their creators; we are the “Frankenstein”, and we have created some very cute and intelligent “monsters.”

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