The Rescue Society: Scientific Research

The Rescue Society is a scientific organization that conducts andcompiles peer reviewed scientific canine behavior research for public benefit.

The scientific research The Rescue Society is conducting is ongoing canine behavior study to develop best practices, higher standards and an understanding of the applicability principles for working dogs in various, differentiating environments utilizing pertinent research to establish alternative policies for proactive and productive pilot initiatives that test new program models for solutions to environmental and economic activities.

The Rescue Society exists to serve, support and applaud various special interests or special needs environments, situations and people. The Rescue Group is passionate and resolved to make the world a better place by addressing, quantifying and qualifying the amazing and miraculous value that the human-dog bond connection and its utilitarian values possess and present and combining in all its forms and functions which elevates and provides greater potential to the overall plight of the human race for both humans and dogs.

What Are Dogs Thinking?

posted May 24, 2012, 4:41 PM by Charles Henderson   [ updated May 24, 2012, 4:49 PM ]

Researchers at Emory University have discovered that while you may have a pretty good idea of what your canine companion is contemplating, scientists took it one step further by training dogs to sit still in MRIs. 
When we peer into those big brown eyes, we think we know what thoughts lie behind them. Sure, we can tell when our dogs are happy, when our dogs are sad, and when our dogs are scared, but how can we ever know what they are really thinking?

Brain Scan of Dogs

Researchers at Emory University -- the same school where kids are invited to play with dogs during finals to help reduce stress -- decided to collect and compare images of dogs' brains in an effort to uncover canine cognition.

Gregory Berns, the lead researcher and director of the Emory University Center for Neuropolicy, got the idea to work with dogs after learning about the dog who was part of the Navy SEAL team who went in after Osama bin Laden. He figured that if a dog can be trained to leap out of a helicopter, then a dog can be trained to undergo an fMRI.


Callie wears ear protection as she prepares to enter the scanner. Photo by Bryan Meltz.

The study is in its early stages, but by recording which areas of the brain are activated by different stimuli, researchers are hoping to answer whether dogs are capable of empathy, whether they can discern emotions in their human companions, and how much language they actually comprehend. So far the initial research dogs, Callie and McKenzie, have shown that dogs -- unlike any other animal -- pay extremely close attention to humans.

Callie and McKenzie are making incredible contributions to science with their safety and comfort in mind. Berns said, "From the outset, we wanted to ensure the safety and comfort of the dogs. We wanted them to be unrestrained and go into the scanner willingly.” The dogs have been trained to lie perfectly still in the brain-scanning machines with their heads supported by a chin rest and their hearing protected by ear muffs.

The first results have been published in the Public Library of Science, and with continued research, Berns hopes to further decipher the minds of dogs.






 Callie training in a scanner simulator

Story and photos via Emory University eScienceCommons

Diagnostic Accuracy of Canine Scent Detection in Early & Late Stage Lung & Breast Cancers

posted May 15, 2012, 11:51 PM by Charles Henderson   [ updated May 16, 2012, 12:40 AM ]

Michael McCulloch, Tadeusz Jezierski, Michael Broffman, Alan Hubbard, Kirk Turner,

and Teresa Janecki


Lung and breast cancers are leading causes of cancer death worldwide. Prior exploratory work has shown that patterns of biochemical markers have been found in the exhaled breath of patients with lung and breast cancers that are distinguishable from those of controls. However, chemical analysis of exhaled breath has not shown suitability for individual clinical diagnosis.



The authors used a food reward-based method of training 5 ordinary household dogs to distinguish, by scent alone, exhaled breath samples of 55 lung and 31 breast cancer patients from those of 83 healthy controls. A correct indication of cancer samples by the dogs was sitting/lying in front of the sample. A correct response to control samples was to ignore the sample.


The authors first trained the dogs in a 3-phase sequential process with gradually increasing levels of challenge. Once trained, the dogs’ ability to distinguish cancer patients from controls was then tested using breath samples from subjects not previously encountered by the dogs.


The researchers blinded both dog handlers and experimental observers to the identity of breath samples. The diagnostic accuracy data reported were obtained solely from the dogs’ sniffing, in double-blinded conditions, of these breath samples obtained from subjects not previously encountered by the dogs during the training period.


Results: Among lung cancer patients and controls, overall sensitivity of canine scent detection compared to biopsy-confirmed conventional diagnosis was 0.99 (95% confidence interval [CI], 0.99, 1.00) and overall specificity 0.99 (95% CI, 0.96, 1.00). Among breast cancer patients and controls, sensitivity was 0.88 (95% CI, 0.75, 1.00) and specificity 0.98 (95% CI, 0.90, 0.99).


Sensitivity and specificity were remarkably similar across all 4 stages of both diseases.


Conclusion: Training was efficient and cancer identification was accurate; in a matter of weeks, ordinary household dogs with only basic behavioral “puppy training” were trained to accurately distinguish breath samples of lung and breast cancer patients from those of controls.


This pilot work using canine scent detection demonstrates the validity of using a biological system to examine exhaled breath in the diagnostic identification of lung and breast cancers.


There is a pdf file with the entire 12 page research study located in The Rescue Society Research Files & Documents link in the directory on the leftside of the website as well as attached as a file below. 

Minds of Animals: The cognitive abilities of non-human animals by Alexandra Horowitz

posted Oct 15, 2009, 1:24 AM by Charles Henderson   [ updated Apr 22, 2012, 8:52 PM ]

When Your Dog Reads Your Subtle Cues

Do dogs notice details? Do we?
Published on February 25, 2011 by Alexandra Horowitz, Ph.D. in Minds of Animals

 Every animal cognition researcher lives in Clever Hans's shadow. This horse was clever, but not in the way that people thought he was. Hans lived in Berlin at the turn of the twentieth century. His owner, a Mr. von Osten, had trained him to do arithmetic (or so his owner believed). Given a multiplication or division problem, Hans tapped out the answer with his hoof. He knew factors, decimal places; he could count the people present in a room, or the number of bespectacled people present in a room. Given a new problem, Hans was unerringly correct. Hans went, in the parlance of our time, global: crowds lined up to see the famous counting horse. Suddenly the possibly hidden and latent intelligence of animals was on everyone's mind. Skeptics lined up, too, but not until one Oskar Pfungst, a psychologist, came along, did they have their proof. Pfungst demonstrated that Hans was using cues unintentionally provided by his owner or anyone asking Hans questions. Without being aware of it, they were telling him when he'd reached the final answer with their bodies: relaxing their shoulders, tilting their head, widening their nostrils, and so on. These subtle acts were Hans's clue to stop tapping.

I think Hans was pretty clever, myself. He didn't need to learn arithmetic: he could just get the "answers" from the humans around him. But his is a cautionary tale to behavioral scientists: beware of inadvertent cueing. This is especially relevant in studies looking at animals' performance in experimental tests, because often the animal acts in interaction with a human experimenter. Is the chimp indicating which of two piles of M&Ms is larger because he knows which is larger, or because the human accidentally glances at the larger pile?

Today, researchers do a good job of avoiding the pitfalls of inadvertent cueing. But when thinking about how dogs behave, "cueing" takes on a new dimension. For dogs are especially sensitive to a myriad of cues that indicate what we humans, the ones who bred them and brought them into our homes, are going to do. Dogs' sensitivity to cues is in some sense, as with Hans, what makes them so "smart". They predict us; they follow our smallest gestures; they seem to know us.

The cues we give are often subtle. We might not even know that we are giving a different cue, when we rise from our chairs to go to the fridge, as opposed to rising to take the dog for a walk. Your dog does.

I was thinking about the subtlety of cues when reading a paper which might speak about cues we give to dogs. In this paper, the authors (Lit et al, 2011) tested 18 drug- and explosive-detection dogs and their handlers. The teams were told to search for the scent of drugs or explosives in an experimental room. Only, there were no none there. However, the handlers had been told that some of the locations were baited. And in the end, the teams "found" the presence of the scent again and again. Of course, they were wrong every time: there were no drugs nor explosives present.

These were experienced teams, who have clearly proven their abilities to find hidden contraband. So what was happening? It appears that the handlers, thinking there were scents present where there weren't, cued the dogs. At least, that is what has been reported. I read about the paper in Scientific American, whose headline read, in part, "When dog handlers believed there were drugs or bomb materials, their dogs called more false alarms".

Is that true? It's a subtle point, but the headline isn't quite right. The team called more false alarms. That is, the handlers reported that the dog found the drug. Two things could have happened, and the study's data does not distinguish between them. Either the handlers tipped off the dogs to what they thought were correct locations -- the Clever Hans "effect" -- or the handlers simply misreported what the dogs were doing. They might have "thought" or "sensed" that they saw the dog alert to a scent. This is classic confirmation bias: you see what you expect to see. An experienced handler expects to see his dog find the scent.

The study is presented as a cautionary tale against cueing a dog, but I think it is also a cautionary tale about research: the findings are often more subtle than the later headlines will tell you. Look more closely. (Your dog certainly is.)

Cited: Lit, Lisa, Schweitzer, Julie B., Oberbauer, Anita M. 2011. "Handler beliefs affect scent detection dog outcomes." Animal Cognition (on-line).

SWGDOG is a Scientific Working Group

posted Oct 13, 2009, 12:58 AM by Charles Henderson   [ updated May 2, 2012, 6:59 PM ]

SWGDOG is a collaboratively funded effort of the FBI, NIJ and DHS.


SWGDOG is not a certification group.


SWGDOG is a Scientific Working Group.


For more than a decade, there have been scientific working groups (SWGs) established initially sponsored by the FBI. The purpose of these working groups is to establish professional forums in which federal, state, and local government experts, together with academic and commercial scientists and other recognized experts in the selected field can develop optimal operational guidelines.

Recently, it has become increasingly clear that local law enforcement as well as national homeland security can benefit from improvements in the performance of deployed detector dogs and their proper combination with electronic detection devices. A variety of leaders in the detection canine and instrument community support the establishment of a scientific working group in this area, and there has already been some standardization efforts in this area that can be drawn from.


At the 2nd and 3rd National Detector Dog Conferences held in 2001 and 2003, general best practices for detector dog teams were drafted and refined. Also, an Interpol European Working Group on the Use of Police Dogs in Crime Investigation (IEWGPD) recently concluded a similar project in Europe and representatives would be included in this working group.

An exploratory meeting to ascertain if valid justification and broad support could be demonstrated to adopt a formal SWG on dogs and orthogonal detector guidelines  was held in Burbank, California, on January 15, 2004, and convened a core group of more than a dozen recognized experts, both domestic and international, in the field of dog and orthogonal detection from the federal, state, and local governments as well as recognized expert private practitioners in the United States.


As such, its mandate focuses on the meld of what’s known scientifically and how to use this knowledge to augment the skills of canine handlers and supervisors within the law enforcement community and private sector.


A standard can be defined as an established or widely recognized modelof authority or excellence, as a reference point against which other things can be evaluated, or the ideal in terms of which something can be judged. Standards usually define or establish uniform specification or characteristics for products or services.


A minimum standard is defined as the lowest acceptable criteria that define

or establish uniform specification or characteristics for products or services.


Why was SWGDOG established?


SWGDOG was established in order to benefit local, state, federal and international law enforcement agencies by improvements in the performance and overall reliability of detector dogs and their optimized combination with electronic detection devices.


SWGDOG benefits:


• national security

• border protection

• drug and contraband interdiction

• law enforcement and criminal investigations

• disaster response


Establishing best practices for detection teams improves interdiction efforts as well as courtroom acceptance of dog alert evidence by improving the consistency and performance of deployed detector dogs.

              Approved Guidelines

        * SC1 Terminology (abcdefghijk)
        * SC2 General Guidelines
        * SC3 Selection of Serviceable Dogs
        * SC4 Kenneling and Healthcare
        * SC5 Selection of Handlers
        * SC5 Canine Career Field Progression System

        * SC6 Presentation of Evidence in Court
        * SC7 Research and Technology
        * SC8 Substance Dogs: Accelerants
        * SC8 Substance Dogs: Agriculture

        * SC8 Substance Dogs: Contraband
        * SC8 Substance Dogs: Explosives

        * SC8 Substance Dogs: Human Remains
        * SC8 Substance Dogs: Narcotics

        * SC8 Substance Dogs: Pest & Insect

        * SC9 Scent Dogs: Article Search

       * SC9 Scent Dogs: Avalanche Search

        * SC9 Scent Dogs: Location Checks

        * SC9 Scent Dogs: Non-specific Human Scent Wilderness Area Search
        * SC9 Scent Dogs: Pre-Scented Canine Aged Trail

        * SC9 Scent Dogs: Scent Identification Lineups

        * SC9 Scent Dogs: Searching for Live People in Disaster Environments

        * SC9 Scent Dogs: Track/Trail People based on Last Known Position

        * SC10 Statement of Purpose

Documents for Public Comment
Posted for Public Comment 4/24/2012 - 6/22/2012

Documents listed with "Track Changes" have been previously approved and are being modified after required two year review. Please find below two versions of each document for easier reading.

    * SC1l Terminology CLEAN
    * SC1l Terminology TRACK CHANGES
    * SC2 General Guidelines CLEAN
    * SC2 General Guidelines TRACK CHANGES
    * SC3 Selection of Serviceable Dogs & Replacement Systems CLEAN
    * SC3 Selection of Serviceable Dogs & Replacement Systems TRACK CHANGES
    * SC9 Searching for Human Remains in a Disaster Environment

Supporting Files:
SWGDOG Public Comment Form (*.doc)
SC1l Terminology CLEAN (*.pdf)
SC1l Terminology TRACK CHANGES (*.pdf)
SC2 General Guidelines CLEAN (*.pdf)
SC2 General Guidelines TRACK CHANGES (*.pdf)
SC3 Selection of Serviceable Dogs & Replacement Systems CLEAN (*.pdf)
SC3 Selection of Serviceable Dogs & Replacement Systems TRACK CHANGES (*.pdf)
SC9 Searching for Human Remains in a Disaster Environment (*.pdf)

Too dog tired to avoid danger: Self-control depletion in canines increases behavioral approach toward

posted Oct 13, 2009, 12:58 AM by Charles Henderson   [ updated Apr 22, 2012, 6:43 PM ]

Too dog tired to avoid danger: Self-control depletion in canines increases behavioral approach toward
an aggressive threat.

Holly C. Miller & C. Nathan DeWall & Kristina Pattison &

Mikaël Molet & Thomas R. Zentall

# Psychonomic Society, Inc. 2012

This study investigated whether initial selfcontrol

exertion by dogs would affect behavioral approach

toward an aggressive threat. Dogs were initially required to

exert self-control (sit still for 10 min) or not (caged for

10 min) before they were walked into a room in which a

barking, growling dog was caged. Subject dogs spent 4 min

in this room but were free to choose where in the room they

spent their time. Approaching the unfamiliar conspecific

was the predisposed response, but it was also the riskier

choice (Lindsay, 2005). We found that following the exertion

of self-control (in comparison with the control condition),

dogs spent greater time in proximity to the aggressor.

This pattern of behavior suggests that initial self-control

exertion results in riskier and more impulsive decision making

by dogs.

Keywords Self-regulation . Dogs . Decision making . Risk

taking . Impulsivity

The potential for danger is ubiquitous. To avoid danger, people

often exert self-control over their behavior (Baumeister, 1998;

Baumeister, Heatherton & Tice, 1994). When people fail to

exert self-control and behave more impulsively, they may

unintentionally put themselves in harm’s way (Freeman &

Muraven, 2010). Pedestrians jaywalk across busy streets,

children stick objects into electrical outlets, and teenagers

join dangerous gangs. The failure to exert self-control

and avoid these dangerous activities is likely affected by

many individual variables (e.g., demographics, personality).

However, a common mechanism that may be responsible for

human and nonhuman self-control vigor may also play a role

(Miller, Pattison, DeWall, Rayburn-Reeves & Zentall, 2010).

The present research tested this hypothesis by examining

whether dogs approach dangerous situations when their ability

to exert self-control is compromised.

Research with human and nonhuman animals suggests

that self-control relies on a limited resource (Baumeister &

Heatherton, 2004; Miller et al., 2010). Exerting self-control

depletes this resource, and once depleted, subsequent efforts

to control behavior become impaired. For example, when

humans control their impulse to eat fresh cookies (in comparison

to when they inhibit eating radishes), they then

persist for a shorter time on an unsolvable puzzle task

(Baumeister, Bratslavsky, Muraven & Tice, 1998). Dogs

behave similarly. When dogs control their physical movement

(in comparison with when self-control is not needed

because they are physically constrained by a cage), they

persist for a shorter duration on a subsequent unsolvable

puzzle task (Miller et al., 2010).

Extensive research with humans suggests that this phenomenon

is domain general, suggesting that tasks that require selfcontrol

negatively affect performance on a wide variety of

subsequent tasks (for a review, see Baumeister, Schmeichel &

Vohs, 2007). Decision making, for example, is negatively

affected by initial self-control exertion. Depleted subjects, as

compared with their nondepleted counterparts, take more risks

and gamble more (Bruyneel, DeWitte, Franses & Dekimpe,

2009; Freeman & Muraven, 2010; Molet, Miller, Laude, Kirk,

Manning & Zentall, 2012). To date, however, there is no

evidence that initial self-control exertion affects subsequent

H. C. Miller (*) : M. Molet

Université de Lille, Nord de France,

Domaine universitaire du “Pont de Bois”, Rue du Barreau,

BP 60149, 59653 Villeneuve d’Ascq Cedex, France


C. N. DeWall : K. Pattison : T. R. Zentall

University of Kentucky,

Lexington, KY, USA

Psychon Bull Rev

DOI 10.3758/s13423-012-0231-0

behavior in more than one domain for nonhuman animals, nor

is there evidence that depleted humans or nonhuman animals

are more likely to inadvertently subject themselves to risks that

may result in physical harm.

Some recent evidence suggests this possibility, because

self-regulatory depletion increases approach motivation

(Schmeichel, Harmon-Jones & Harmon-Jones, 2010) and

behaviors with an approach-related motivational direction,

such as aggression (Denson, Pedersen, Friese, Hahm &

Roberts, 2011; DeWall, Baumeister, Stillman & Gailliot,

2007; Finkel, DeWall, Slotter, Oaten & Foshee, 2009).

Consequently, the purpose of the present investigation was

to determine whether self-regulatory depletion has domaingeneral

consequences on nonhuman animal behavior and to

examine the likelihood that depletion would cause dogs to

put themselves in harm’s way by approaching a physically

threatening target. We chose dogs, in part, because, like

humans, they are highly social animals that establish social

dominance hierarchies and need to be sensitive to social

cues provided by other members of their species.

We adopted a two-task procedure used widely in the

human self-control literature (Baumeister, Bratslavsky,

Muraven & Tice, 1998). Dogs were tested twice, individually,

and we varied the requirements of the first task between

sessions. In the first task, either the dog was required to sit

still for 10 min (self-control depletion), or the movement of

the dog was constrained by placing it inside of a cage for the

same duration (control). Next, the dog was brought into a

room in which it encountered a caged, barking, and growling

dog. Dogs spent time in this room, but their behavior

was unconstrained. Thus, dogs could choose to spend their

time near the aggressor, or they could stay farther away.

Although dogs are predisposed to approach and investigate

unknown conspecifics (Lindsay, 2000), in this context, it

was the more dangerous thing to do. Greater proximity to a

confined aggressive dog, despite the confinement, is associated

with a greater risk of an aggressive encounter (American

Veterinary Medical Association, 2011; Lindsay, 2001, 2005;

Sacks, Sattin & Bonzo, 1989). Consequently, staying near the

aggressor was defined as the riskier (more impulsive) choice,

and avoidance was defined as the safer (less impulsive)

choice. We predicted that self-control depletion, as compared

with the control condition, would increase approach-related

behavior toward the threatening dog.



We recruited 10 dogs (Canis familiaris; 4 males, 6 females)

ranging from 12 to 120 months of age (M 0 48.8 months).

All dogs belonged to private owners, would immediately

approach a friendly caged dog, and had been trained to

maintain an out-of-sight sit–stay for 10 min. They had also

been trained to remain calm inside a cage for as long as 6 h.


A bath mat was placed on the floor in front of an empty dog

cage (1.2 m long × 0.8 m wide × 0.9 m high) that was

surrounded by a ProSelect™ exercise pen (see Fig. 1). The

dogs sat on this mat during the self-control manipulation.

This mat was placed inside a second dog cage (0.9 m long ×

0.6 m wide × 0.7 high) at the same location during the

control condition. A mirror was placed strategically on the

wall so that the experimenter could watch the dogs from

outside of the room through a small opening in the door. To

increase the difficulty of the self-control depletion phase, an

electronic “hamster” (Zhu Zhu pets®) was placed inside an

Adventure Ball™ and was activated inside the room during

the self-control depletion phase (see Fig. 1).

A highly dominant dog (an 11-year-old female bull terrier)

with a disposition for guarding territory was placed in a

dog cage (1.2 m long × 0.8 m wide × 0.9 m high) that was

surrounded by the ProSelect™ exercise pen. This dog

would bark and growl continuously whenever it was confined

and another dog was visible. The intensity of this

display was greater when its owner was close by, suggesting

that the dog included its owner as part of its territory to

defend (Borchelt, 1983; Lindsay, 2001). For this reason, the

owner (O) stood next to the dog during testing.

Fig. 1 The experimental room as it was set up for the self-control

manipulation that preceded the impulsivity test

Psychon Bull Rev

For safety reasons, the pen that was placed around the cage

provided an additional distance of 0.3 m between the aggressive

dog and the subject dog. The room (3.9 m long × 3.8 m

wide) was demarcated into zones by lines made with Scotch®

masking tape (2.5 cm wide; see Fig. 2). The first of four lines

was 61 cm from the screen (zone 1), and zone was 61 cm deep

(zones 2, 3, and 4). Because there were doors in zones 1 and 4

and standing near a door should be considered an escape

behavior rather than an approach behavior, we chose to define

this zone separately. The dog was considered in door space if

its front two feet were within 30 cm of the door and the dog's

body was pointing in the direction of the door.

In the first phase of the experiment, the door (B) was left

slightly ajar; however, both doors were closed during the

second phase of the experiment. Two video cameras were

used to record each testing session; one was mounted on a

tripod to the left of the aggressive dog, and an experimenter

who was to the right of the dog operated the other camera.


Pretesting At least 1 week before testing, all subject dogs

were introduced to a friendly caged dog. All subject dogs

approached the caged dog upon being released from leashed

restraint. The purpose of this testing was to ensure that

subject dogs were predisposed to approach an unknown

conspecific and that some level of inhibition would be

required for avoidance. In addition, subject dogs were

leashed and were exposed to the Zhu Zhu® hamster to

ensure that they were interested in but not frightened by it

when it moved. This assessment eliminated the possibility

that fear would confound the self-control manipulation.

Testing All dogs were tested with both conditions of the

self-control manipulation (order was counterbalanced). In

the self-control depletion condition, the dog was cued to

“sit” and “stay” by Experimenter 1 (E1). Following the cue,

E1 activated the Zhu Zhu® hamster and exited the room

through door A while the dog maintained its position. The

hamster was used to increase the difficulty of the selfcontrol

task. With the door slightly ajar, E1 watched the

dog (without being seen by the dog) via a strategically

placed mirror. The dog was allowed to keep visual track of

the hamster but if the dog moved from its position, E1

returned and gave the sit–stay cue again. A second experimenter

(E2), who stood outside of the testing room (behind

door A), recorded the number of cues and the time at which

each cue was given. The dog remained alone in the room

with the electronic hamster for a total of 10 min.

When the dog was released, it was given a small piece of

wiener (1 g), was moved to an adjacent room, and was

praised for 30 s by E1. After the subject dog left the testing

room, the aggressive dog was led into the newly vacant

room through door B by its owner (O) who was blind to

the self-control manipulation. The aggressive dog was

placed inside the cage, and O stood next to the cage behind

the exercise pen during testing. Once the aggressive dog was

situated, E1 entered the room with the subject dog (which

caused the aggressive dog to start barking and growling),

quietly walked the subject dog across the room on leash, and

unleashed it at a predesignated spot without further interaction

(black dot in Fig. 2). E1 then filmed the subject dog’s

behavior for 4 min while quietly standing still and looking at

the dog only via the screen of the digital camera. At the end

of 4 min, E1 leashed the subject dog and removed it from

the experimental room through door B.

In the control condition, E1 placed the subject dog inside

a dog cage and was told by E2 to return to the dog and

“recue” it to get inside of the cage at the same times she had

previously cued the dog during the self-control condition. If

the dogs’ first test session was in the control condition, it

was revisited by E1 three times at minutes 1, 5, and 7 during

the 10 min. This was the average number of revisits required

in a previous experiment (Miller et al., 2010). During the

control condition, the electronic hamster was inside the

room but was not activated. Pilot research indicated that

the hamster attracted attention from dogs during the sit–stay

but that, when activated while caged, it caused some dogs to

whine, circle, and paw. The remaining procedural variables

were held constant between conditions. Dogs were tested

between the hours of 09:00 and 15:00. A video clip displaying

the dogs’ behavior during the control manipulation

can be found at


An observer, who was blind to the subjects’ condition,

Fig. 2 The experimental room as it was set up for the impulsivity test used a digital stopwatch to time the duration that subject

Psychon Bull Rev

dogs spent in each zone. A second blind observer coded

10% of the observations to obtain a reliability measure.

There was a positive Pearson correlation between the two

observers, r 0 .99, p < .01.


The dogs responded differently in the two conditions. The

dogs generally spent more time in zone 1 and near the doors,

especially following the self-control condition. The proportion

of time spent in each zone and near the door appears in Fig. 3.

A two-way repeated measures analysis of variance

(ANOVA) analyzed the differences of time spent in the

zones (+doors) across conditions (self-control, control).

Time spent in the room did not differ as a function of

condition because total time was equated, but the time spent

in the zones was significantly different, F(4, 36) 0 5.06, p <

.01, and the dispersion of time spent in zones was significantly

affected by self-control condition, F(4, 36) 0 2.56,

p 0 .05. Subsequent analyses were run to examine the

observed differences. A one-way repeated measures

ANOVA examining the effect of zone for the self-control

condition found that there was a very reliable effect of zone

following self-control exertion, F(4, 51) 0 6.08, p < .01, but

not following the control condition, F(4, 51) 0 1.88, p 0 .13.

When the simple effects of zone within each condition (selfcontrol,

control) were analyzed, it was observed that following

self-control exertion, dogs reliably spent more time in

zone 1 than in 2, 3, and 4, F(9, 36) 0 13.29, 15.75, 16.17,

respectively, all ps < .01, but not more time than near the

doors, F(9, 36) 0 3.67, p 0 .06. Following the control

condition, dogs did not spend a significantly different

amount of time between zones 1 and 2, F(9, 36) 0 2.13,

p 0 .15, but they did spend a significantly greater time in

zone 1 than in zones 3 and 4, F(9, 36) 0 5.67, 5.54, all

ps 0 .02. Here again, time spent in zone 1 did not differ from

time spent at the doors, F(9, 36) 0 1.95, p 0 .17.

Planned comparisons using two-tailed correlated samples

t-tests were performed on the difference scores in each zone

between the two conditions. The difference was significant

in zone 1, t(9) 0 3.11, p 0 .01 (dogs spent more time in zone

1 following the self-control condition), and in zone 2, t(9) 0

2.39, p 0 .04 (dogs spent more time in zone 2 following the

control condition), but it was not significant in either of the

other two zones (or near the doors), all ts < 1.2. As was

predicted, self-control depletion caused dogs to spend a

greater percentage of time in the zone nearest to the aggressive

dog (58.9%), as compared with the control condition

(41.8%). The data from individual dogs in both the selfcontrol

and control conditions appear in Fig. 4.


Avoiding danger enhances an animal’s ability to survive and

reproduce. Yet there are often occasions when the need to

avoid danger is paired with a natural tendency to approach.

To keep out of harm’s way, animals override their natural

impulse to approach in order to remain safe and secure.

When animals have limited self-control resources, they

may make more impulsive decisions that put them in harm’s

way. The present experiment examined whether initial exertion

of self-control would increase impulsivity in dogs,

resulting in risky decisions.

Our results supported this prediction. When dogs were

depleted, as compared with when they were not, they were

less able to inhibit their predisposed approach behaviors. As

a result, dogs approached an aggressive dog more when

depleted than when nondepleted.

Our interpretation of the present results rests on the

assumption that it is dangerous to approach a confined

aggressive dog and that subject dogs were risking their

safety by approaching. Although in the context of the present

experiment, strict precautions ensured the safety of all of

the dogs, confinement is not fail-proof in the natural world,

and it is quite possible that a confined aggressor could

escape and attack. Mail carriers are often attacked by presumably

confined dogs, as are children, and a significant

percentage of pet-related human fatalities result when a

restrained aggressive dog is approached (Sacks et al.,

1989; U.S. Postal Service, 2011). Moreover, moving away

from an aggressor defending its territory reduces the motivation

for attack (Lindsay, 2001).

present experiment, experimenters observed that the

aggressor displayed a more intense threat display when

subject dogs were near the fence and the intensity decreased

as subject dogs moved farther away. This observation

is similar to others regarding territorial behavior and

confinement (Calhoun, 1962; Klopfer, 1969; Lindsay,

2001; Pettijohn, Davis & Scott, 1980). It is also evidence

that approaching was relatively more risky than avoiding

the caged aggressor.

Another way of looking at the dogs’ behavior is as an

increase in counter aggression, provoked by the confined

aggressor. This complementary hypothesis is founded on

research demonstrating that humans, who typically suppress

emotionally driven aggressive responses, are more

likely to retaliate aggressively when they have depleted

their self-control. More specifically, when students initially

deplete their self-control by inhibiting their consumption

of a donut (but not a radish), they are less able

to control their aggressive behavior when they are subsequently

provoked (i.e., they are negatively evaluated

on a previously written essay). Depleted students retaliate

by adding more hot sauce to food intended for the

essay evaluator. Similarly, when students are initially

required to control their attention (inhibit reading words

displayed to them) and are subsequently given a negative

essay evaluation, they are more likely to administer

aversive noises to the essay evaluator. Furthermore,

following self-control exertion, students are more likely

to report the desire to inflict physical harm on someone

who provokes them (DeWall et al., 2007).

In the context of the present experiment, it is difficult to

delineate the role that increased aggression may have

played. Increased approach behavior may reflect counter

aggression, or it may reflect an increase in approach motivation.

Self-regulatory depletion increases approach motivation

in humans in the absence of aggressive intentions

and, thus, may have also contributed to the pattern of behavior

we observed in dogs (Schmeichel et al., 2010).

The commonality between human and nonhuman animals

is great, and the present research is further evidence

that human self-control has phylogenetic roots. It is also

further evidence that a phenomenon (i.e., depletion) once

believed to be uniquely human can be modeled with

dogs. Such modeling may have great empirical value,

since it may provide greater insight into the physiological

and neurobiological processes that affect self-control

vigor. Research with animal models will not supplant

that on cognitive factors involved in human selfregulation,

but it will augment our understanding of the

fundamental and biological rudiments of a phenomenon

that is clearly multifactorial in nature. Therefore, we

believe that social psychology will benefit by incorporating

work with nonhuman animals to extend existing


Author Note We thank Byron Nelson for his help with data analysis.


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