a review of domestic dogs human-like behaviors

8/9/2019 A Review of Domestic Dogs Human-like Behaviors

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A REVIEW OF DOMESTIC DOGS (CANIS FAMILIARIS) HUMAN-LIKE BEHAVIORS: OR WHYBEHAVIOR ANALYSTS SHOULD STOP WORRYING AND LOVE THEIR DOGS

MONIQUEA. R. UDELL AND C. D. L. WYNNE

UNIVERSITY OF FLORIDA

Dogs likely were the first animals to be domesticated and as such have shared a common environmentwith humans for over ten thousand years. Only recently, however, has this species behavior been subjectto scientific scrutiny. Most of this work has been inspired by research in human cognitive psychologyand suggests that in many ways dogs are more human-like than any other species, including nonhumanprimates. Behavior analysts should add their expertise to the study of dog behavior, both to addobjective behavioral analyses of experimental data and to effectively integrate this new knowledge intoapplied work with dogs.

Key words: gestures, object permanence, theory of mind, social cognition, dogs

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DOGS IN HUMAN SOCIETY

That the dog is a loyal, true, and affectionate friendmust be gratefully admitted, but when we come toconsider the psychical nature of the animal, the limitsof our knowledge are almost immediately reachedSir John Lubbock. (1889, p. 272)

Our Intertwined Past

Sir John Lubbocks opinion, outdated

though its language may be, is not aninappropriate summary of the state of researchon dog behavior today. Domestic dogs arenever far away from most peoples lives, butobjective understanding of their behavior isstill surprisingly scarce.

A better understanding of the variablescontrolling dog (Canis familiaris) behaviorcould have practical importance for thegrowing number of industries that utilize thebehavior of domestic dogsnot only in formal

training settings, such as police dogs, drug-sniffer dogs, guide dogs, and so forthbutalso in the public realm, where the linebetween the love of mans best friend andthe fear of so-called bad dogs is a source ofgreat anxiety. In addition, a more completeunderstanding of the role of social stimuli,which develops as a result of a natural historyof operant and classical conditioning within

the domestic dogs home environment, couldplay a crucial role in maximizing the quality ofour interactions with dogs in a variety ofsettings.

Humans and dogs share a long intertwinedhistory. DNA evidence suggests domestic dogsmost likely diverged from wolves in differentplaces at different times beginning as long as135,000 years ago (Vila et al., 1997). This iswhen the morphological structure of certaingroups of wolves began to change to moreclosely resemble the modern domestic dog.Anthropologists and archaeologists have ar-gued that this is an overestimate, claiming thatthe best way to determine the time ofdomestication is to look for signs of a closeassociation between dogs and humans (Morey,2006). One way this has been done is bylooking for evidence of dog burials. Theearliest burial remains of a domestic dog are14,000 years old and were found in Bonn-Oberkassel, Germany (Nobis, 1979). The

dimensions of the well-preserved lower jawand teeth suggest that this animal was domes-ticated and could be compared to a smallsheep dog, making it the oldest knowndomesticated animal and a companion of theCro-Magnon Man in the late Paleolithic age(Nobis, 1979). The time line of dog burialsaround the globe indicates the spread of dogdomestication at different geographic areas(Morey, 2006).

Role of Dogs in Human SocietyThe exact location and lineage of the first

domesticated dog are still under debate, butthe impact that humans have had on the

Address correspondence to Monique Udell and CliveWynne, Department of Psychology, University of Florida,Gainesville, FL, 32611. Email to [email protected].

We thank Ray Coppinger, Leonard Green, Bill Roberts,and John Staddon for most helpful comments on a

previous draft.

doi: 10.1901/jeab.2008.89-247

JOURNAL OF THE EXPERIMENTAL ANALYSIS OF BEHAVIOR 2008, 89,247261 NUMBER2 (MARCH)

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domestic dog as a species is undeniable. Dogsplay an astonishing range of roles in humansociety. Many individuals put their faith inrescue dogs when stranded in the wildernessor capsized in cold water. Others rely on guide

dogs to get them safely to multiple destina-tions on a daily basis. Drug dogs, de-miningdogs, police dogs, termite- and even cancer-detecting dogs are trained and utilized assubstance detectors even in the face ofcompetition from the latest technology. Thereare herding dogs, hunting dogs, sled dogs, andvarious other specializations that are crucial tothe livelihoods of many individuals, not tomention the role dogs play in entertainmentand the pleasures of individual dog owner-

shipsufficiently reinforcing to sustain 74.8million dogs in the United States, at a cost totheir owners of over $100 billion (AmericanPet Products Manufacturers Association,2007).

However, qualities desired in one specializa-tion may not be appropriate in dogs fillinganother capacity. For example, the dependen-cy on human guidance and direction sought incompanion dogs may inhibit a rescue dogsability to problem solve and function indepen-

dently in situations when its handler is out ofsight (Miklosi, Pongracz, Lakatos, Topal, &Csanyi, 2005). It is important, therefore, totake breed specializations and individual his-tory into account when selecting dogs forspecific tasks. The more that is known aboutdog behavior, the more that can be done tomake the training of working dogs as efficientas possible.

A greater understanding of dog behavioralso would be beneficial in a society thatperceives dog attacks and consequent deathsto be a growing problem. The Humane Societyof the United States estimates that 2% of thepopulation is bitten by a dog each year (oversix million people) and ten to twenty of thesebites are fatalwith the victim usually a child(Humane Society of the United States, 2007).Recently, the Minnesota Department ofHealth (2007) reported a 40% increase inthe number of hospital treated dog bitesbetween 1998 and 2005. According to attorneyKenneth Phillips this increase in medically

treated dog bites is representative of anincrease in the dog population at large, whichrose 36% from 1986 to 1994 (Phillips, 2007).The public response to increased media

reporting of dog attacks has been to labelcertain breeds as bad dogs. Malcolm Glad-well (2006) in the New Yorker likened theprofiling of dangerous dog breeds to theracial profiling that has dominated the search

for terrorists since September 11th, 2001. Aswith most forms of prejudice and profiling, thebanning of specific breeds of dogs frommunicipalities (most commonly at presentthe pit bull), fails to effectively identify theenvironmental causes of undesired behavior sothat positive behavior can be reinforced andaggressive behavior controlled with moreenlightened methods. Breed profiling maylead not only to a misguided fear of well-behaved dogs identified with a bad breed,

but may also offer a false sense of securityaround a dog showing warning signs ofaggression just because it comes from a breedwith a good reputation.

Phylogeny vs. Ontogeny

Despite the omnipresence of dogs in humanlives, scientific study of the factors that haveallowed dogs to thrive in human environmentshas until recently been surprisingly meager.

The causes of the characteristic behaviors of

dogs can be understood at two levels. First arethe phylogenetic influences on behavior thatarise as a result of the unique evolutionary pastof domestic dogs. Second, and perhaps moreimportantly (at least in the sense that they areavailable for modification in real time), are theontogenetic causes that are the history ofcontingencies of reinforcement each domesticdog experiences within human society duringits lifetime.

The phylogeny of dogs is particularly inter-esting because, instead of natural selection bythe environment, artificial selection by hu-mans is responsible for the hundreds of breedsof domestic dog that exist today. There is alsoevidence that selection for desirable physicaland behavioral traits has led to many changesin social behavior as unexpected byproducts(Hare & Tomasello, 2005). This has led somescientists to attribute the propensity of dogsfor human social interaction to convergentevolution, where the two genetically distinctspecies were shaped by similar selective pres-

sures (Hare & Tomasello, 2005).There is, of course, no question that genes

play a role in the behavior of domestic dogs,but a dogs individual environmental history

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their inspiration from work on developmentaland cognitive questions in humans and non-human primates. This search for commonpsychological processes in humans and dogshas been motivated by the fact that humans

and domestic dogs have shared a commonenvironment and similar selective pressuresfor tens of thousands of years.

Responsiveness to Human Social Cues

One of the most interesting behavioralcharacteristics of the modern domestic dog isits predisposition to attend and respond tohuman social gestures and cues. Skinner(1953) noted that the behavior of otherindividuals can be an important source of

social stimuli. Gestures and cues are socialstimuli that likely started out as behaviors thatdirectly impacted the behavior of anotherindividual in a reinforcing or punishing way.Skinner gives the example of a policemansstop signal, which could have originatedfrom the action of a man putting out his handagainst another mans chest forcing him tostop. If this were aversive, the second manmight learn to stop before he reached the firstmans upheld hand in future presentations

(Skinner, 1986). Once a gesture is established,an individuals history with the stimulus shapeshis or her behavior in its presence. Thus, if thesocial contingencies are established already forbehavioral responses to a particular gesture,contact with the original behavior that evolvedinto the gesture is not essential. Otherexamples of common human gestures includepointing, nodding, reaching towards some-thing, or glancing between an object andanother individual. Skinner focused on howgestures might come to act as social stimuli inhumans, but the basic principles could easilybe applied to dogs as well. For example, if ahuman throws a dogs ball in a game of fetch,the throwing motion or outstretched armserves as a discriminative stimulus to chasesomething in the direction of the release. Thisreaction most likely ties into the reinforcingeffects of chasing a ball or catching prey alongwith the social reinforcers received for retriev-ing the object. This behavior, of following thedirection of an outstretched arm, may gener-

alize to less dynamic forms of the stimulus, andthe dog may begin to follow gestures such aspointing or fake tosses to static objects to beretrieved. The use of gestures could undoubt-

edly be shaped in many species through thisprocess over time, but dogs appear to demon-strate a sensitivity for human gestures thatmany other nonhuman species lack (Brauer,Kaminski, Riedel, Call, & Tomasello, 2006;

Hare, Brown, Williamson, & Tomasello, 2002).Responses to gestures usually are tested in

an object-choice paradigm. In this test, areinforcing object is hidden in one of two ormore locations or containers. The subjectenters the test area, and a gesture is given toindicate the location of the object. Alternativehiding places are equated for smell and othercues and are usually sham-baited to control forthe effects of noise and human scent. The dogis then allowed to approach the containers and

indicate a choice by touching or comingwithin a required distance of one of thelocations.

Miklosi, Polgardi, Topal, and Csanyi (1998)carried out the first study investigating the useof human social cues by domestic dogs.Modeled primarily on studies with humansand nonhuman primates, two bowls were usedto hide food items in an object-choice para-digm. One of the bowls was baited out of sightof the subject; the location of the food was

determined by a coin toss with no bowl beingbaited more than twice in a row. The dog thenwas led back into the room and was held3 meters from the bowls. The experimenter,who stood behind the bowls, made eye contactwith the dog and then gave the predeterminedgesture. The experimenter then returned to aneutral position and the dog was allowed toindicate its choice by approaching one bowl. Acorrect choice resulted in food reinforcementand an incorrect choice ended the trial withno reinforcement. Five gestures were used inthis study: pointing, bowing (bending theupper torso), nodding, head-turning, andglancing with the eyes only. Each gesture waspresented a minimum of 30 times before thenext was introduced. All dogs experienced thegestures in the order given here. To progressto the next gesture, 80% accuracy had to bemet for the previous condition.

All 6 pet dogs in this study were able to usepointing, head nodding, bowing, and headturning to identify the target bowl without

explicit training in the first fifteen trials, andthe only significant initial difference amongdogs was the ability to use gazing as adiscriminative stimulus (Miklosi et al., 1998).



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Subsequent studies have analyzed a wider setof gestures and found dogs that can use, or betrained to use, various types of pointing withthe arm or extensions of the arm (Hare &Tomasello, 1999; Miklosi et al., 2005; Miklosi

et al. 1998; Soproni, Miklosi, Topal, & Csanyi,2001; Soproni, Miklosi, Topal, & Csanyi, 2002;Udell, Giglio & Wynne, 2008), glancing(Miklosi et al. 1998; Soproni et al. 2001; Udellet al., 2007), local enhancement by a humanspresence near the target (Hare & Tomasello,1999), and a human placing a token on atarget (Hare & Tomasello, 2005; Udell et al.,2008).

Other studies of the exploitation of humangestures by dogs have varied the way in which

conditions are presented. Instead of a hierar-chical series of gestures in which one gesturemust be learned to criterion before the next isintroduced, some studies have presentedconditions in orders that vary across subjectsand thus control for the effects of generaliza-tion from one gesture to another (Brauer etal., 2006). Others have used probe methods toinsert novel gestures into a series of trained orfamiliar gestures such as pointing (Soproni etal., 2002). These studies have largely support-

ed the conclusions from the pioneering workof Miklosi et al. (1998), suggesting that Miklosiet al.s positive conclusions were not artifactsof having the dogs master one gesture typebefore proceeding to the next.

Particularly noteworthy in these studies ofdog responsiveness to human gestural cues, isthat some of the successful dogs in thesestudies had only had minimal contact withhumans or did not live as pets in humanhouseholds. Miklosi et al.s (1998) study

included 5 assistant or guide dogs that didnot reside in a typical household setting andyet still performed above baseline in thepointing and bowing conditions in the first15 trials.

The degree to which individual dogs attendto human social cues and their tendency torapidly integrate new behaviors into theirrepertoire based on the consequences thatfollow from them, says something about boththeir development and their environment. For

dogs to provide adaptive responses to humangestures requires not only attentiveness andclose proximity to human action, indicative ofsome sort of social attachment to humans, but

also sensitivity to context within a humanenvironment.

This conclusion gains strength from recentresearch on the role of context in the trainingof basic commands, such as sit and come.

Fukuzawa, Mills, and Cooper (2005) demon-strated that unintentional human cues influ-ence how dogs respond after training. Dogswho responded to the commands sit andcome reliably when a human was giving thecommand, showed declines in performancewhen the command was given by tape recorderin the humans presence, and declined furtherwhen the human wore tinted sunglasses.Furthermore, when the human experimentergave the two commands from behind a screen,

out of sight of the dog, the dogs respondeddependably to the come command but notto the sit command (Fukuzawa et al., 2005).This finding makes sense when the context oftraining and previous exposure is considered.Come is often applied and reinforced whenpresented from a greater distance or when thedog is out of sight, whereas the sit com-mand is usually given and reinforced onlywhen the dog is in close proximity to thehuman issuing the command.

Ability to Cue Humans

Most research in the area of social cues hasfocused on the dogs response to humangestures, but a study by Miklosi, Polgardi,Topal, and Csanyi (2000) found that dogs thathad seen a food item or a toy hidden in aspecific bowl placed out of their reach whiletheir owner was out of the room, were able tocommunicate to their owner the location ofthe hidden target item when he or shereturned. These dogs showed a significantincrease in mouth licking, vocalization, sniff-ing, looking at the owner, and looking at thelocation of the hidden object after the toy hadbeen hidden and the owner returned. Vocal-izations and gaze directed at the location ofthe hidden object were also higher when theowner was present than when the dog was leftalone after hiding, although both behaviorsoccurred in both conditions (Miklosi et al.,2000). Gazing between the owner and thelocation of the food or toy occurred an average

of three times in the first minute, with 8 out of10 dogs looking first at their owner and then atthe location of the hidden item (Miklosi et al.,2000). This suggests that the dogs remem-

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Gacsi, Miklosi, Varga, Topal, and Csanyi(2004) concluded that the body orientationand eye visibility of a human also has an effecton the begging behavior of dogs. Dogs weregiven the opportunity to approach and beg

from one of two women holding sandwiches.In one condition the two women faced thedog: One with a blindfold on her head, andthe other with a blindfold over her eyes. In theother condition one woman faced the dog andtried to maintain eye contact without movingher head or body, whereas the other womanfaced away from the dog and ignored it. Dogswere given a piece of food no matter whomthey begged from in each trial. Nevertheless,in both conditions, dogs begged significantly

more from the seeing or attentive individualsthan from the other woman.Research of this kind often has been used in

support of the possibility that dogs possess atheory of mind or ability to adopt theperspective of others (e.g., Brauer et al.,2004; Gacsi et al., 2004). However, suchperformances also could be due to pastexperience with similar contingencies. Whenfood is forbidden, taking the food while ahumans face is oriented to the food and

visible to the dog would likely be punished.However, taking food in situations where thehumans face is not appropriately oriented ismore likely reinforced by obtaining the foodand less likely to be punished. Furthermore, ifbegging from a person who is looking at a dogusually leads to reinforcement and beggingfrom someone who is not oriented towards thedog does not (as might occur at a familydinner table), then reinforced begging behav-ior directed towards attentive individualsshould increase whereas nonreinforced behav-ior towards nonattentive individuals shoulddecrease. Despite the fact that reinforcementwas available for begging from either womanin Gacsis study, a long history of beggingwould increase the probability of begging froman attentive person in the first place, and thedog may never come into contact with thenew contingencies. Furthermore, it is possiblethat a dog reared with different contin-gencies in place, for example one that onlysuccessfully obtains food when humans are not

looking, would show the exact oppositebehavior. In this case it is not theindividuals theory of mind which is atstake, but rather the development of a

foraging strategy based on the greatest chanceof reinforcement.

Word Learning

In 2004 Science published a report of an

exceptional border collie named Rico. Ricocould recognize vocal labels for over 200 items,mostly toys, which he retrieved by name.Kaminski, Call, and Fischer (2004) demon-strated that Rico also was able to identify anovel item from a group of familiar items andwould retrieve the novel item in response to anunfamiliar item name in 70% of trials.Exclusion learning and fast mapping were saidto occur, and Rico was credited with not onlypairing an unfamiliar name with a novel item

but remembering the new name for the novelitem in later testing sessions.

Ricos vocabulary is certainly impressive andsuggests the potential dogs may have forlearning associations between items and hu-man vocal cues. However, Ricos ability to fastmapor pair items with a novel name afterone associationwas far from perfect. Whenhe was given the name of one of the previouslynovel items ten minutes after the first pairing,Rico retrieved the correct item out of a pile of

nine toys in four out of six trials. However,when tested an hour after the first pairings,using a different set of items, his performancedropped to retrieving the correct item in threeout of six trials (Kaminski et al., 2004).

The study with Rico raises interestingquestions about the capacity dogs have forname learning and the amount of exposurerequired to learn the names of new objects.But more research is needed before theimplications of his performance become clear.

Questions that remain open include: Is Ricoan exceptional dog, or could his achievementsbe replicated in other dogs given appropriatetraining? What might the necessary andsufficient training regimen be to train a dogto respond to vocal labels in this way? What isthe limit of a dogs vocabulary? How does adog generalize to words pronounced indifferent ways and by different individuals?

Individual and Breed Differences

It is a widely accepted part of the commonlore that different breeds of dogs showcharacteristic behavioral patterns and apti-tudes, and that individual dogs differ in their



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temperaments. In an attempt to quantify theselay impressions, Svartberg (2004) developedthe dog mentality assessment (DMA). Theassessment consists of a battery of tests, such asthe dogs reaction to social contact, play, chase

games, passive situations, strangers, suddenappearances of objects, and loud noises.Factor analysis on these scores led to theidentification of six traits: playfulness, chase-proneness, curiosity/fearlessness, sociability,aggressiveness, and distance-playfulness. Fol-low-up questionnaires indicated the stabilityand value of the DMA for predicting broaderpersonality dimensions, such as a placementalong a shynessboldness continuum (Svart-berg, Tapper, Temrin, Radesater, & Thorman,

2005). However, the DMA has been lesssuccessful at identifying and predicting long-lasting aggressiveness and nonsocial behavior-al problems (Svartberg, 2004; Svartberg et al.,2005).

Evidence for inherent breed and sex differ-ences, as measured with the DMA, is limited.One study indicated that high scores on theboldness scale do not correlate with the breedor sex of a dog. However, breed and sexappear to play some role for the lower scoringdogs, of which female German Shepherds andthe other tested breed of working dog, BelgianTervurens, scored lower than male GermanShepherds (Svartberg, 2002). Furthermore, alater study (Svartberg et al., 2005) indicatedthat scores on all six personality traits did notvary significantly by breed types divided intoherding dogs, guarding dogs, and gun dogs.This is not to say that differences do not existbetween individual breeds; however, thesource of these differences does not seem tobe explained by the current personality tests or

models. More tightly controlled behavioralmethods, focusing on individual differencesand specific behavior problems, may havemore success at getting to the root of theenvironmental influences that shape thesedifferences in behavior.

DISCUSSION

Social vs. Causal Cues: The Difference Between Dogsand Nonhuman Primates

Ever since Darwin (1859), the search forhuman-like social cognition (i.e., behaviorcontrolled by human and conspecific socialcues similar to that observed in humans) has

focused on our closest genetic relatives,particularly chimpanzees. Though much re-mains controversial in this field, it seems clearthat chimps and several other species ofprimates are only modestly successful on many

tasks designed to test for human-like socialreasoning. Thus, chimpanzees are only able tofollow gaze and show joint attention under alimited set of conditions (Barth, Reaux, &Povinelli, 2005). In the object-choice taskdescribed above, few chimpanzees or othernonhuman primates are able to use gaze orother social cues such as pointing to identifythe location of a hidden object (Call, Hare, &Tomasello, 1998; Call & Tomasello, 1998;Itakura, Agnetta, Hare, & Tomasello, 1999;

Povinelli, Reaux, Bierschwale, Allain, & Simon,1997; Tomasello, Call, & Gluckman, 1997).Successful individuals typically need dozens ofrepeated exposures to the cue, and show poortransfer after even small changes to the testingenvironment (Brauer et al., 2006; Call, Ag-netta, & Tomasello, 2000; Itakura et al., 1999).

Dogs, in contrast, though they share muchless of our genetic material than do chimpan-zees, nonetheless show a spontaneous ability tofollow human gestures to find reinforcing

objects, even in the absence of training inthe laboratory. Most remarkably, even dogsraised with minimal human contact can followa human point and gaze gesture withoutexplicit training (Hare et al., 2005).

Chimpanzees also have been the speciesmost intensely studied for any ability torespond to the attentional state of humans orconspecificsso-called Theory of Mindabilities. However, several published studieshave failed to find any evidence of a sensitivityto anothers knowledge (e.g., Brauer et al.,2006; Povinelli & Eddy, 1996), and studies thatdo suggest this ability (e.g., Hare & Tomasello,2004) have been subject to extensive criticism(e.g., Boesch, 2007; Heyes, 1998; Penn, Ho-lyoak, & Povinelli, in press). Dogs, in contrast,respond readily to human cues in these kindsof tests (e.g., Brauer et al., 2004; Call et al.,2003; Gacsi et al., 2004).

Chimpanzees have been by far the mostintensively studied species for the comprehen-sion of human language (including seminal

studies by Gardner & Gardner, 1969; Savage-Rumbaugh et al., 1993; Terrace, 1979), but nopeer reviewed paper has ever claimed therapid fast-mapping of language acquisition



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found by Kaminski et al. (2004) in the dogRico.

Several theories have been proposed toexplain why dogs perform so well on tasksinvolving socially mediated stimuli. The possi-

bility that dogs learn to attend to human socialcues simply because of the intensity of theirinteractions with humans appears to be refut-ed by the observation that even puppies anddomesticated fox kits that have had onlyminimal exposure to human beings, nonethe-less respond very accurately to human cues inchoice paradigms (Hare et al., 2005).

Hare and Tomasello (2005) considered thepossibility that domestic dogs high sensitivityto social cues is an evolutionary legacy inher-

ited from wolves, the dogs closest wild relativeand progenitor. If general social traits com-mon to wild canids have simply been inheritedby domestic dogs, then wolves also should dowell on tasks involving social cues. However,when compared to wolves and wild foxes,domestic dogs (including puppies) makesignificantly more correct responses on choiceparadigms where social cues serve as thediscriminative stimuli (Hare et al., 2002; Hare& Tomasello, 2005). This is true even though

the wolves tested had been socialized andraised by humans in their homes as pets. Thus,it does not seem that domestic dogs simplyinherited the predisposition to attend to socialstimuli from wolves.

Hare and Tomasellos (2005) study includ-ed, alongside tests on domestic dogs, compar-ison tests on fox kits that had been selectivelybred over 46 years for nonaggressive behaviortowards humans. These fox kits were com-pared to others reared under the sameconditions but not selectively bred for lowaggression. Neither group of foxes had beenraised in human homes (nor had the earliergenerations from which they were descended).Hare and Tomasello found that the fox kitsbred for nonaggressive reactions to peopleperformed just like domestic dog puppies onpointing and gazing tasks. The fox kits thathad not been selectively bred performedpoorly on these tasks, at a level similar to thatseen in wolves (Miklosi et al., 2003).

These results suggest that during domesti-

cation, traits that were often selected byhumans, such as lack of aggression andfearlessness towards people, may have carriedwith them other genetic traits that led to a

heightened responsiveness to human socialstimuli (Hare et al., 2002; Hare & Tomasello,2005). It also is possible that by removinggenetic tendencies towards aggression andfear towards humans, other preexisting social

behaviors were no longer blocked and thuscould increase in frequency.

If selective breeding and domesticationserve as a likely explanation for the success ofdomestic dogs on tasks involving human socialcues, then that begs the questionWhy dontother domesticated animals share these abili-ties? In fact, domestic cats have been shown tobe only slightly less successful than dogs inusing basic pointing cues to find a hiddenfood item in a simple choice test (Miklosi et

al., 2005). However, when presented with anunsolvable task, where food was hidden in abutter pot but tied to a stool in such a way thatretrieval was impossible, dogs looked betweenthe problem and their owner more often andfor longer periods of time, whereas cats onlyoccasionally looked towards their owners andspent much more time trying to get the foodthemselves. This may indicate that: (1) Duringdomestication cats were selected for traits lesstied to the approach of humans and fear

reduction, or (2) less stringent contingenciesexist for cats in their home environmentleading to behavior that is more independentof human action, or both.

The lower responsiveness and less frequentorientation of cats to human cues may in factbe related to the fact that domestic cats arecloser to their wild relatives than dogs are towolves. The domestic cat (Felis catus) showsonly a low level of genetic divergence from itstwo nearest wild relatives (the Europeanwildcat, F. silvestris, and African wildcat, F.libyca), and the earliest evidence for cat domes-tication is only around 8,0009,500 years BPconsiderably more recent than that for dogs(between 14,000 and 135,000 years BP) (Dris-coll et al., 2007; Serpell, 2000; Vigne, Guilaine,Debue, Haye, & Gerard, 2004). The traitsselected for in the domestication of the twospecies also may have led to differences in theresponsiveness and attentiveness each hastowards humans. Even today, many dog breedsare selectively bred to work in close association

with humans, filling specific roles in industriessuch as farming, therapy, police, and search-and-rescue. Even with earlier partnershipssuch as hunting it is quite probable that a



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dog that stayed close to its owner or was quickto respond to its owners actions would havebeen a more beneficial working companion,securing its place in the group and ultimatelyin the gene pool.

Cats were likely used as mousers and kept aspets from early in their domestication (Vigneet al., 2004), but they are not typically bred forpurposes that require a close partnership withhumans, even today. Thus, a house catsindependence could have actually been abeneficial trait that increased the chances ofits survival in the same environment. Further-more, cats are often chosen as pets becausethey are considered low maintenance com-pared to dogs. They do not require walking,

they sleep or entertain themselves most of theday, and they are typically small and quietenough to go unnoticed much of the time.Thus, there are many more opportunities forcats to engage in independent behaviorswithout immediate human consequences with-in the home environment.

Several studies have looked for key similar-ities and differences between wolves and dogs.Perhaps the most striking developmentaldifference between dogs and wolves is that,whereas dogs can be socialized to humanswithin the first sixteen weeks of life, wolvesmust be removed from their mother forhuman socialization before fourteen days ofage, or acceptance of humans is very unlikely(Klinghammer & Goodman, 1985).

Implications for Phylogeny and Ontogeny

In a study by Frank and Frank (1982),domesticated dogs (Alaskan malamutes) andwolf pups that were raised in identical condi-tions in a home environment showed distinctdifferences in both physical and social devel-opment. Conducted as a two-stage experiment,2 malamutes acquired at 10 days old werecompared to 2 wolf pups acquired at 11 daysold a year before. The wolf and dog pups didnot interact, but the conditions were keptalmost identical for the two groups during theexperiment. Interestingly the two major dif-ferences were that wolves were given moresocialization to humans, as they were requiredto sleep with their human foster parent two

out of every three nights as pups, and themalamutes, who did not receive this extrasocialization, were given slightly more frequentexposure to the outdoor enclosure. All pups

were nursed by the same wolf mother untilweaning, at which point they were hand raisedand fed by humans.

The wolves reached several physical devel-opmental landmarks days ahead of the mala-

mutes. For example, the wolf pups beganclimbing over their 45-cm pen wall at only19 days, whereas the malamute pups could notclimb over their 15-cm den box opening at32 days old. However, socialization of thewolves was much more difficult than of themalamutes. At 2 weeks of age the wolf pupsavoided the human handlers whenever possi-ble and hid behind the wolf dam whenhumans approached. At 6 weeks they becameless fearful but somewhat indifferent to the

human presence, preferring to be aroundadult wolves or dogs in the enclosure. Themalamutes, in contrast, became more inde-pendent of the nursing wolf, and activelyapproached nearby humans and engaged ingreeting frenzies on a regular basis (Frank& Frank, 1982).

However, this study has some potential flaws.First, all of the pups were raised by a wolf fostermother, which could have potentially impact-ed the behavior of the mother to the foster

pups or the behavior of the growing pupstoward the foster mother. Without a compar-ison using a Malamute foster mother for bothspecies it is impossible to say that having asame-species foster mother would not producea closer bond to that individual and thereforeless of a bond towards humans. Second, sincethe two groups of pups were raised at differenttimes, other factors may have been present inone study that were not accounted for in thenext, for example, the age of the foster motheror other canine group members and theprevious experience of the experimentersraising wolfs before raising the Malamutes.

To address some of these concerns, Kubinyi,Viranyi and Miklosi (2007) conducted asimilar study comparing the developmentand behavior of wolf pups and mongrel dogpups in foster homes with human caretakers.In this study, all pups were individuallyassigned to a human caretaker who handraised and fed his or her pup from 4 to 6 daysold. Both sets of pups participated in multiple

behavioral tests from 3 to 9 weeks of age.When the wolves reached 9 weeks of age theyhad to be integrated into a captive wolf pack,but were still visited by their caretakers at least



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once or twice a week. Unfortunately themongrel dogs in the study continued to livein a human household at this point, so testinglater in their lives could have been impactedby different home environments. Nevertheless,

the study found that the wolves could behandled by their caretakers similarly to dogswhen tested between 1 and 2 years of age. Thisincluded coming when called, sitting and lyingdown on cue, allowing dog accessories such asa muzzle to be put on, and minimal social andphysical neophobia. The level of attachment,measured by the length of time the wolvesspent in close proximity to their caretaker at 1to 2 years of age, however, was less for wolvesthan it was for the dogs. The domestic dogs

also out-performed the wolves on tasks involv-ing more complex human social cues, such asmomentary distal pointing. The wolves couldbe taught to use the same level cues as thedogs at 11 months, but only after extensivetraining (Kubinyi et al., 2007).

Studies comparing domestic animals andtheir closest genetic relatives are a good step inthe direction of identifying the role phylogenyand ontogeny play in key behaviors thatseemingly make the species behaviorally dis-

tinct. However, much care needs to be takento make sure both species are treated equiva-lently and that the behavior that results is not abyproduct of some unintended aspect of theexperimental environment. This includes tak-ing into account genetic and developmentaldifferences that may impact how differentspecies respond to stimuli when presented atthe same age or in different environments.

The fact that various domesticated animalsdo better than their nondomesticated relativeson tasks requiring the use of human socialstimuli indicates that selective breeding anddomestication play some role in this class ofbehavior. These genetic traits or predisposi-tions may have been a result of artificialselection in some species, but they are still aproduct of the evolutionary history of thatspecies. Instead of mountains creating thegeographic isolation of a pack of wolves, stonewalls and chains may have determined whichindividuals could breed. In place of a naturaldistribution of ecological resources, a human

hand may have determined which individualswould live or die within a pack.

Dogs may have developed at least somebehaviors similar to those of humans because

the two species lived in such close proximityover 10,000 years. It also is the case that itwould have been beneficial to humans tocreate similar or complementary social traitsin these animals through selective breeding.

Of course, over most of this history of artificialselection, the human breeders would haveunderstood nothing of genetics or selectivebreeding. Simple operant conditioning wouldbe sufficient to explain the selection of dogswith desirable traits. Dogs that bit or attacked ahuman may have been killed, whereas onesthat worked well with humans on the hunt andwere nonviolent to their owners were takencare of and had a greater chance of reproduc-tive success. Over time, people would have

learned to recognize traits in puppies that hadtypically led to aggressiveness in older dogs inthe past, and the process of selecting desiredindividuals and rejecting ones with undesir-able traits would have become more efficient.In other words, the selection of particulartraits in dogs would be reinforced with thepresence of cooperative, nonaggressive dogs,whereas the tolerance or selection of othertraits might be punished with aggressiveattacks or a lost investment of food and energy

if a fearful dog runs away.Of course, phylogeny may set the limits ofwhat is possible in behavior, but it is ontoge-nythe personal history of reinforcementthat determines what an animal actually does.In a study by Hare and Tomasello (1999),domestic pet dogs demonstrated the ability touse the location and gestures of both humansand other dogs to help locate hidden food.Four conditions were used: humanlocalenhance (the human squatted by the correctlocation); doglocal enhance (another dog satby the location); humangaze- and-point; anddoggaze-and-point (the other dog faced andlooked towards the location). When perfor-mance was assessed as a group, the 10 subjectdogs in the study found food significantlymore often in each of the experimentalconditions than in the control or baselinecondition where no cue was provided. As agroup, no one condition appeared to be morehelpful than another. However, individualdogs differed greatly in which stimulus they

were most successful in using to find the targetlocation. Only 2 dogs were successful in allfour conditions, 1 dog was successful in threeconditions, 2 dogs were successful only with



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the human communicator, 2 only with the dogcommunicator, 1 during both the humanand doglocal enhancement conditions only,and 2 during the humanlocal enhancementcondition only. These differences are most

likely due to different levels of experience inthe home with situations similar to the onesthe experimenters set up in the laboratory.

Dog Profiling Revisited

If, then, there is a genetic component tosome aspects of behavior that have a clearimpact on humandog interaction, can banstargeting bad dog breeds such as pit bulls, orprofiling based on genes in general, be justifiedby maintaining the position that behavior is a

product of genetic tendencies as well? Evidencesuggests that the answer is no. Although bitesand deaths attributed to pit bulls are up inrecent years (Sacks, Sinclair, Gilcrist, Golab, &Lockwood, 2000), other breeds have beennumber one for aggression against humans atother times. German shepherds and St. Ber-nards were estimated to be responsible for themajority of deadly dog attacks, not includingpolice dogs, from 1975 through 1980 (Pinckney& Kennedy, 1982). In the 1970s, Dobermans

were on the top of the list (Randall Lockwoodof the ASPCA, as cited in Gladwell, 2006), andbetween 1993 and 1998 Rottweilers were themost dangerous dog breed (Sacks et al., 2000).However, these estimates are imperfect becausethey do not take into account the baselinepopulations of each breed in the U.S. at anygiven time, and identifying an individual as aspecific breed is not always clear cut. Therefore,breeds that have a larger population may beinvolved in more attacks than less popularbreeds but proportionally may be less aggres-sive; and aggressive dogs that do not fall clearlyinto a breed category are often labeled as abreed that is already deemed aggressive, there-by inflating the numbers for that breed.However, even in times where one breed mayshow proportionally higher levels of aggressivebehavior, there is evidence that this is not solelydue to an inherited bad dog gene. In fact,the type of owner, not the breed of the dog, isthe best predictor for dog attacks (Gladwell,2006; Siebert, 2004). In a quarter of fatal dog

attacks, the owners previously had been arrest-ed for illegal fighting, and many aggressive dogsare ones that have been abused, starved, ordeprived of medical attention. In addition,

some owners seek out breeds that have areputation as bad dogs and then shape theaggressive behaviors that later seal their fate.According to Randall Lockwood, a senior vice-president of the ASPCA, A fatal dog attack is

not just a dog bite by a big or aggressive dog. Itis usually a perfect storm of bad humancanineinteractionsthe wrong dog, the wrong back-ground, the wrong history in the hands of thewrong person in the wrong environmentalsituation (cited in Gladwell, 2006, p. 26).

Dogs may become problems in humansociety because their owners may also respondin unconventional ways to social stimuli withinthe environment because of their own histo-rypossibly exposing their dog to contingen-

cies governed by an abusive, isolated, orneglectful home environment. Therefore, tofully address these and other types of behav-iors demonstrated by domestic dogs, thespecific contingencies that surround the oper-ant and the specific properties of social stimulithat serve as effective discriminative stimulineed to be identified and defined.

Dogs: Our Closest Relatives?

It may sound strange, but it is not unrea-

sonable to view dogs and humans as subject toconvergent evolution (Hare & Tomasello,2005). Over the last 100,000 years, the socialenvironments of domestic dog pups andhuman children have become more and moresimilar to each other, and less like those ofeither species closer genetic kin.

It is as a consequence of this intensecohabitation that dogs have come to emulatesome behaviors that are commonly viewed asuniquely human, such as the recognition of

anothers attentional state. These kinds ofcomplex behaviors are commonly structuredin relatively vague cognitive terminology. Wehope this review will inspire behavior analyststo use the empirical tools of our field toinvestigate just how closely dog social behaviormaps onto human use of social cues. Suchresearch could answer fascinating questions inthe evolution of complex behavior, as well asenabling us to live more safely and profitablywith our best friends.

To Shape, Lead, Catch, or Click?

The study of dog behavior may seem new toexperimental behavior analysis, but the inter-



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est in applying behaviorist technology to dogtraining dates back to Skinners own writings.Skinner wrote: Since nearly everyone at sometime or other has tried, or wished he knewhow, to train a dog, a cat, or some other

animal, perhaps the most useful way to explainthe learning process is to describe some simpleexperiments which the reader can performhimself (Skinner, 1951/1999, p. 605). Hewent on to provide techniques to shape thebehavior of any animal the reader couldcatch using the basic principles of positivereinforcement (Skinner, 1951/1999). Threedecades later, Karen Pryor reintroduced be-havioral methods of dog training to a newgeneration of animal trainers and pet owners

(Pryor, 1984).Notwithstanding Skinners and Pryors en-

couragement to behavior analysts to becomeinvolved in dog training, and even a paper inthe psychological literature calling on behav-ioral scientists to become more involved in thescientific development of dog training meth-ods (Tuber, Miller, Caris, Halter, Linden, &Hennessy, 1999), the two flagship journals ofthe field, the Journal of the Experimental Analysisof Behavior and the Journal of Applied Behavior

Analysis, have published surprisingly few em-pirical papers involving dogs as subjects, themost recent (Cohen, 1970) having a publica-tion date of over 35 years ago.

Surely there would be no better way toconvince people of the effectiveness of scien-tific behavioral techniques than to providethem with the technology that they desire toaddress their current needs. Now is the time toprovide the research that will help behavior-ists, and in turn society, better understand the

behavior of domestic dogs as a species, and todevise refined and easily applied methods oftraining and evaluation grounded in empiricaland testable approaches to behavior.

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Received: July 12, 2007Final acceptance: October 10, 2007


a review of domestic dogs human-like behaviors

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