Final thesis
The secure base effect in dog (Canis familiaris) –
owner relationship
Sofie Sernekvist
1 Abstract
………………………………………….1
2 Introduction
2.1 Background
2.2Aims of the project
3 Methods
3.1 Equipment and procedure for heart rate measuring
3.2 Equipment and procedure for saliva cortisol measuring
4 Experiment I
4.1 Materials and methods
4.1.2 Experiment 1 A
4.1.3 Experiment 1 B
5. Experiment II
5.1 Methods
6. Results test I
6.1 Test I A
6.2 Test I B
7. Results test II
8. Discussion
8.1 The effect of separarion
8.2 The effect of the threatening stranger
8.3 General discussion
9. Acknowledges
10. References
1 Abstract
In this study three different experiments were performed to investigate the secure base effect
in family dogs. The stimuli were threatening approach of a stranger and separation from the
owner. Earlier studies proved behavioural effect to the stimuli (Topál et al. 1998, Vas et al.
2005) so in this study also the physiological parameters heart rate and saliva cortisol were
investigated. 34 (test I) + 46 (test II) dogs of different breeds, gender and age were balanced
and used in three tests. Test 1A investigated changes in cortisol level affected of separation
from owner and handled by a friendly stranger. In test 1B the heart rate response to a
threatening approach of a stranger was measured both when the owner was present and
absent. 1B contained a separation tests and a nine episodes test where the dogs carried a
harness with ECG equipment during the test. Test number 2 was a threatening approach with
owner present or absent and separation from owner. Here the dogs only participated for one
trial and their cortisol level was measured. In all tests the dogs showed more or less
behavioural response to the stimuli. In test 1A and 2 no change in the cortisol level was
found. In the 1B test, significant results were found in heart rate affected of the threatening
approach. Heart rate increase was also found to be connected to behavioural response in this
population of dogs. A secure base effect could be revealed for the reactive dogs. According to
the results, behaviour is connected to heart rate but not saliva cortsiol. Saliva cortsiol should
be used in more intensive stress situation than in this experimnet.
Key words: dog, heart rate, saliva cortisol, secure base, separation, thretening approach,
2 Introduction
2.1 Background
The secure base effect is defined by the ability to discriminate and respond differentially to
the object of attachment, in this case owners of dogs. It also means that the owner will have a
calming effect on the dog in a novel situation. The secure base effect is a part of the
attachment. Proximity and the proximity maintenance are the major behavioural indicators of
attachment between owner and dog. It is also showed in parent-infant humans as well, though
the spatial distance to the object of attachment is not as important for the attached individual
as its availability or accessibility (Bowlby, 1972). More complex operational criteria of
attachment have been developed by other researchers. They claim that attachment presumes
(a) an ability to discriminate and respond differentially to the object of attachment (securebase effect), (b) preference for the attachment figure (proximity and contact seeking), and (c)
response to separation from and reunion with the attachment figure that is distinct from
responses to others (Cmic, Reite, & Shucard, 1982; Gubernick, 1981; Rajecki, Lamb, &
Obmascher, 1978).
Dog-human attachment is an asymmetrical relationship that is based on dependence
mirroring adult-child relationship (Ben-Michael 1995). It can be interpreted in the framework
of social attachment (Serpell 1996). Dogs’ attachment toward a human is qualitatively
different from the relationship with conspecifics. Tuber et al. (1996) have found that in novel
environment stress (measured as cortisol level) can be decreased by the presence of a familiar
human but not by a familiar dog. This suggests that the relationship toward humans has a
special importance and might be the result of evolutionary adaptation to the human
environment. Under certain conditions such as the loss of the attachment figure (parent or
owner), both dog and child may develop analogue behaviour disorders like psychogenic
epilepsy, asthma-like conditions, ulcerative colitis, anorexia nervosa (see Fox, 1968; 1975;
Overall 2000).
The Strange Situation Test (SST), developed by Ainsworth and Wittig (1969) is a
widely accepted test to measure the attachment relationship between mother and child. It is a
laboratory procedure that is based on the operational criteria for manifestation of attachment
(Rajecki et al. 1978). During the test situation attachment behaviour is activated by
separation from and reunion with the attachment figure that is used as a “secure base”.
Recently, without substantial changes this method was utilized to test attachment behaviour
in dogs (Topál et al. 1998; Gácsi et al. 2001; Prato-Previde 2003; Topál et al. 2005). In
contrast to the human psychological test, however, in the case of dogs, a behavioural analysis
was performed comparing the behaviour of dogs toward the owner and a stranger. Statistical
analysis based on multivariate methods confirmed similarities between the attachment
specific behaviour patterns of dogs and children. Follow up work provided evidence that in
dogs this pattern of attachment is stable over at least one year and is independent from the
peculiarities of the testing location (Gácsi, 2003). A post-hoc factor analysis resulted in three
meaningful factors that seemingly separated three key aspects of behavioural structure:
Factor 1 contained behaviours related to the "stress-evoking" capacity of the situation. Factor
2 consisted of variables describing "attachment" toward the owner and factor 3 was
associated with behaviours related to the "acceptance" of the stranger (Topál et al. 1998). An
important further analogy to the human case has been revealed by observing the emergence
of attachment behaviour in shelter dogs (Gácsi et al. 2001, Marston et al. 2005). Such
propensity of adult individuals to develop novel attachment relationship is at present
described only for humans and dogs. Although in all studies satisfactory evidence was found
for the special relationship of dogs and their owners. Prato et al. questioned if these results
really support the existence of the “secure base effect”, which is claimed to be one of the
major factor of mother-child attachment relationships.
Here in this study we investigated possible relationships among behavioural variables
and physiological parameters (heart rate and cortisol level) in dogs measured in separation
and while being approached by a threatening stranger. The advantages of using physiological
parameters and non-invasive methods such as saliva cortisol and heart rate level are of big
importance because the dogs are not getting physically affected during the test. The methods
can also be a help when poor welfare in animals are investigated. With a saliva sample the
level of saliva cortisol can be measured and used as a stress indicator. Saliva sample
compared to blood sample is a more ethical and less problematic method but also reduces the
risk of that the animals get stressed of the sample taking itself. Saliva cortisol concentrations
have been shown to correlate well with plasma cortisol in several species including humans
and dogs (Barnett and Hemsworth, 1990). In this case the objects are free to move around
compared to when heart rate is measured where the dogs need to carry equipment during the
test. Periods where the dogs are absolutely still are used to measure the heart rate because
only the effect of the dogs´ inner state should be calculated. This method could be used to
evaluate psychological stress in family dogs and data can be collected over a long time
(Maros et al. 2007 in press).
Hypothesis 1 – Experiment 1A, Experiment 2
H0: Dogs’ cortisol level does not change after a separation from the owner in an unfamiliar
environment.
H1: Dogs’ cortisol level will increase after a separation from the owner in an unfamiliar
environment.
H2: Only those dogs’ cortisol level will increase after a separation from the owner in an
unfamiliar environment, which behaviour would reflect distress during the separation.
Hypothesis 2 – Experiment 2
H0: The (change in) dogs’ cortisol level is not affected by the presence or absence of the
owner when a threatening stranger approaches the dog in an unfamiliar environment.
H1: The dogs’ cortisol level is affected by the presence or absence of the owner when a
threatening stranger approaches the dog in an unfamiliar environment.
H2: The dogs’ cortisol level is affected by the presence or absence of the owner when a
threatening stranger approaches the dog in an unfamiliar environment depending on the dog’s
behavioural response.
Hypothesis 3 – Experiment 1B
H0: Dogs’ heart rate and is not affected by its separation from the owner in an unfamiliar
environment.
H1: Dogs’ heart rate will increase during a separation from the owner in an unfamiliar
environment.
H2: The change in the heart rate during a separation from the owner would depend on their
distress during the separation measured by behavioural variables.
Hypothesis 4 – Experiment 1B
H0: Dogs’ heart rate is not affected by the threatening approach of a stranger in an unfamiliar
environment.
H1: Dogs’ heart rate will increase during the threatening approach.
H2: Dogs’ heart rate will increase during the threatening approach depending on their
behaviour during the approach
Hypothesis 5 – Experiment 1B
H0: The presence of the owner has no effect on dogs’ heart rate level during the threatening
approach.
H1: The presence of the owner lessens the increase in the dogs’ heart rate level during the
threatening approach.
2.2 Aims of the project
All the above results were based on the detailed analysis of behavioural data. The present
study has two major aims.
1. We wanted to reveal the relationship between the behavioural and hormonal and/or heart
rate response in dogs in two moderately stressful situations; a) separation from the owner, b)
being approached by a threatening stranger.
2. We were looking for behavioural and physiological evidence in support for one major
prediction the theory of human analogue individual attachment in dogs; that dogs use their
owners as a secure base in moderately stressful situations.
Topál et al. (1998) provided evidence for dog-human attachment and a secure base
effect that is the major factor in the mother-child attachment. With this background we
developed two tests for secure base. In the tests we wanted to investigate the effects of the
separation and the approach of a stranger separately. Moreover, instead of observing the
effect of an approaching friendly stranger (as in the SST), we decided to face the subjects
with a threatening type of approach (Vas et.al.)
3 Methods
3.1 Equipment and procedure for the heart rate measuring.
To measure the heart rate of the subjects, a telemetric system (ISAX – Integrated System for
Ambulatory Measurment and Spectral Analysis of Heart Period Variance) - developed by
Láng and co-workers was used. ISAX consists of portable equipment for 24 hour ambulatory
measurement of ECG. It is carried by the dog in a special designed harness conveniently
during the whole experiment (Fig. 1).
The ISAX machine is a box (10 * 15 * 2 cm)
and has a weight of 300g. The data are read
and processed in a computer and later on
translated to heart rate. (average heart rate
beep per minute).
In order to fix the electrodes on the body of
the dogs three circles of five centimetres in
diameter on the dog’s torso were shaved
(Fig.2). At the sternal part of reg. cardiac
(exploring electrode), at the right side of reg.
sternalis between the two frontal legs
(indifferent electrode), on the left side at the
border of reg. costalis and reg. sternalis
between the 7th and 8th costae (ground). The
Fig. 1 Dog with equipment
three ECG electrodes (S50 Ag/AgCl) were placed on
Fig. 2 Dog is shaved
Fig. 3 ECG taps are put on
these spots (Fig. 3) and attached with glue and were finally connected by wires to the
recording equipment.
After the test the recording equipment was connected to a personal computer and the raw
data were transferred. R waves of the recorded ECG were detected by using special software
of the ISAX then R-R intervals were measured and stored (Izsó et al. 1999; Izsó & Láng
2000). The R-R interval series were further processed by a ISAX programme. The original RR data were linearly interpolated and resampled at 1 Hz to create an equidistant time series of
R-R-s for analysis (Task Force, 1996; Izsó et al. 1999; Izsó & Láng 2000.) For easier
convenience, these R-R-s that were calculated for each second were further converted to
second by second heart rate (HR) measures (HR: 60 000 / R-R).
3.2 Equipment and procedure for saliva cortisol measuring
The saliva was collected with cotton swabs by an experimenter from the inside of the lips
while the dog was standing still. The soaked cotton swabs were temporarily stored on dry ice
in Eppendorf tubes marked by a number the dog and sample was given. For long term storage
the saliva sample were kept in a deep freezer (-80 ºC). Before the analysis the tubes were
warmed up to room temperature and the saliva was removed from the cotton by
centrifuhation3000 rpm for 15 min) using special centrifuge tubes with filters (Corning SpinX; Sigma-Aldrich, Budapest, Hungary). After separation, the saliva samples were analyzed
for cortisol using a highly sensitive (from 0.003 to 3.0 μg/dl) enzyme immunoassay kit. The
average intra- and inter-assay coefficients of variation were less than 10 and 15%,
respectively (Salimetrics, State College, PA, USA). The procedures were performed on the
basis of the enclosed protocol. Before calculating concentrations log transformations were
used to establish normal distributions.
4 Experiment I
The tests have been carried out at the Department of Ethology, Eötvös University, Budapest,
in two 3.5 m X 5.5 m experimental rooms.
4.1 Materials and methods
Subjects
34 dogs were used, 11 females and 23 males. All of them were living as pets in families and
were from middle sizes to big dogs. The breeds were six Hungarian Vizslas, four Labradors,
two Airedale Terriers, two Border Collies, two Belgian Groenendaels, two Belgian
Tervuerens, one Dogo Argentino, one Hovawart, one Kelpie, one Mudi, one Rhodesian
ridgeback and twelve mongrels. The dogs were used in the different groups (see later) in a
“directional” random way that is they were balanced as much as possible for gender, age and
size. Four dogs were excluded from the 1B test since they showed too much fear of the heart
rate equipment.
4.1.2 Experiment 1/A
Procedure
Part 1A was performed in an empty room with natural light.
1. (Arrival) When the dog arrived with the owner to the department the first saliva sample
was taken and they were placed in the empty room for 25 minutes. The dog was supposed to
be relaxed and calm and the owner had time to fill in a questionnaire about the dog.
2. (shaving) After 25 minutes the second saliva sample was taken and the dog was shaved
and its reactions of the shaving and the duration were noted.
At this point 1A was separated in two suborders:
3. (separation/non separation) After the shaving, half of the groups were separated from their
owners and half were still with their owners in the room. Notes were taking with a 1-0
sampling for 30 sec during five minutes in both groups.
4. (harness put on) Afterwards the harness was put on and the ISAX was tested on the dog.
Notes were taking with a 1-0 sampling for 30 sec during five minutes in both groups and the
same protocol was used.
5. (Reunion) The owners in the non separated groups went to the door and returned
immediately and greeted the dog. The dog was on leash by the experimenter and the
procedure was recorded. The same is done in the separated group but here the owner comes
back after being away for around 15 minutes. The reunion is recorded.
6 (rest ) The dog and owner were together again in the empty room and after 25 minutes the
third saliva sample was taken.
4.1.3 Experiment 1/B
In the room the floor was covered with green linoleum and after each experiment the room
was cleaned by disinfectant to avoid infections and to minimalize the effects of conspecific
odours. The windows in the room were covered with dark curtains to avoid sunshine that
would disturb the cameras and to visually separate the adjacent room.
A pilot study was performed during the early spring with five dogs, (three males and
two females) and the breeds were two Hungarian Viszlas and three mongrels. The pilot study
showed that dogs have big differences in reaction of approaches and separations and also that
the individual heart rate differed a lot. The positions of the dogs also seemed to have an effect
so when the owners were in the room they were asked to keep the dog away from sleeping or
holding its head against the floor or lay on its side. Even when they do not move, different
positions may evoke slightly different heart rate (Maros et al. 2007, in press).
The 1B test was designed for secure base so we also made a shorts test only with
separation. This was performed just before the 1B test started and is called the “corridor test”.
Corridor test
First the dog spent one minute together with the owner in the corridor of the department
(baseline) (Fig. 4). Then the dog was held on leash by the experimenter and could see while
the owner was leaving the department (Fig. 5). The owner called the dog on his name while
walking away. When the owner was out of sight the dog was gently pulled backwards so it
could not see the long corridor from that time (Fig. 6).
Three minutes later the owner came back
and greeted the dog (Fig 7).
Below: Fig 4. Dog with owner
To the right: Fig 5. Owner leaves
Fig.4
Fig.5
Fig.6
Fig.6 separation from owner
Fig.7
Fig. 7 reunion
The test 1B started with a warm up and control for positions.
First the owner and the dog were lead into the test room and the dog could explore for about a
minute. During this time the experimenter explained to the owner what to do during the
episodes. Before the test started, the ISAX was turned on and the dogs had to take different
positions for ten seconds to get their heart rate. The experimenter, always the same woman,
asked the owner to order their dog to “sit,” “stand” “sit”, “lay down” and “sit” for ten seconds
each and measured the time with a stop watch. The ten seconds was measured when the dog
was absolutely still, without any movements with the paws.
Afterwards the dog and the owner were left alone in the room. The dog was kept in a
1.5 meter long leash tiered in the left part of the room and the owner was sitting on a chair at
the wall. The distance between the owner and the dog was 1.5 meter to make it clear if the
dog wanted to approach the owner or stand alone during the episodes.
In the test room, three cameras were used to record the behaviour of the dog. One of the
cameras was placed above the door, to show the dog from the front, and the other two from
the left respectively from the right side of the dog. A fourth camera was placed behind the
dog, pointing at the door to clearly decide when the different episodes started and ended. A
fifth camera was used to record only the sounds. The experimenter used a TV screen that
showed the four cameras to be able to follow the episodes in the room. The time for the
episodes was measured with a stopwatch. With a knocking on the window the experimenter
could communicate with the owner or stranger in the room to push the button or leave the
room. Two orders were set up to avoid an order effect of the threatening approach. In the A
order the dogs face the stranger the first time together with the owner and is later separated
and meet the stranger the second time during separation. The B order dogs are first separated
and then face the stranger during the separation. The second time they meet the stranger are
together with the owner. The last episod with a friendly approach from the stranger is for
etical reason and the data is not calculated.
A order:
Experimenter knocks on the window and the owner pushes the button on the isax.
Episode 1, dog and owner 1
(1min.)
The dog is alone with the owner. The owner can talk to the dog and pet it to make it calm and
not move.
Episode 2 , dog, owner and threatening stranger
(1min.)
The threatening stranger enters the room and steadily gazes at the dog and approaches it
slowly. The owner sits quiet. After one minute the experimenter knocks on the window and
the stranger leaves the room. If the dog is moving or barking continously, the stranger stops
gazing until the dog is quiet or not moving. (This episode can be maximum 90 seconds if the
dog has not been still for 15 seconds during the first minute).
Episode 3, dog and owner 2
(1 min.)
The dog is with the owner. The owner can talk to the dog and pet it to make it calm and not
move. After one minute, a knock on the window signals to the owner to leave the room. The
owner orders the dog to stay and leaves the room.
Episode 4, dog is alone 1
(3 min.)
The dog is separated in the room for the first time.
Episode 5, dog and threatening stranger
(1 min).
The stranger approaches the dog slowly and gazes at the dog. If the dog is moving or barking
continously, the stranger stops gazing until the dog is quiet or not moving. This episode can
be maximum 90 seconds if the dog has not been still for 15 seconds during the first minute. A
knock on the window tells the stranger when to leave the room.
Episode 6, dog is alone 2
(3 min).
This is the second time the dog is separated in the room.
Episode 7, reunion
(1 min)
The owner enters the room and greets the dog while standing next to it and tries to make it
still. After a minute the experimenter knocks on the window and the owner pushes the button
and sits down on the chair.
Episode 8, dog and owner 3
(1 min)
The dog is alone with the owner. The owner can talk to the dog and pet it to make it calm
and not move.
Episode 9, dog, owner and friendly stranger
(1min)
The stranger enters the room, approaches the dog and talks to it in a friendly way. If the dog
doesn’t aloud the stranger to pet it, the stranger sits down and calls it by its name. After one
minute the experimenter knocks on the window and the stranger pushes the button.
B order:
Episode 1, dog and owner 1 (1min.)
Episode 2, dog is alone in the room (3min.)
Episode 3, dog and threatening stranger (1 min).
Episode 4 dog is alone in the room 2 (3 min.)
Episode 5, reunion (1 min.)
Episode 6, dog and owner 2 (1 min).
Episode 7, dog and owner and threatening stranger (1 min)
Episode 8, dog and owner 3. (1 min).
Episode 9, dog and owner and friendly stranger (1min)
Data analysis
The recorded material was analysed in Theme Coder. It measures the time in frames and one
click with the left button on the mouse moves the movie one frame backwards. A click with
the right button on the mouse moves the movie one frame forward. 25 frames are one second.
The real time for the experiment was calculated from the frames.
Raw data from Theme Coder was put in to excel and the coded behaviours were separated
from each other with colours. Periods without movements, position change and barking was
considered as periodes where only the psychological state could affect the heart rate and the
duration of these periods was calculated. All periods longer than five seconds were marked
and if they contained tail wagging this was noted. In the coding, the turn on of the ISAX and
all the button pushes was noted and could later on be synchronised with the heart rate from
the ISAX.
The raw data from ISAX was put in a computer and from that one could get the R-R
intervals and button pushes in different files. The heart rate data was put in to an excel file
where the average heart rate for every second during the whole test was calculated.
15 continuous seconds without movements and barking (and if possible tail wagging) was
considered as the optimal and most reasonable sequences to use and it should end five
seconds before the end of the episodes. In the episodes were the owner is leaving the room,
15 seconds before the knocking on the window, is used. In cases where this part of the
episodes contained movements or barking, 15 seconds periods were tried to find as close to
the end as possible, except the five last seconds. If a usable heart rate period was longer than
19 seconds, the heart rate was taken so two seconds of usable heart rate data was left out in
the end (to decrease the risk of source of error). If the period was shorter, 18-16 seconds,
usable heart rate in the beginning was left out and the period continued until the moving or
barking begun. If the only period of 15 continuous heart rate data was found in the end and
contained the five last seconds it was used. Longer periods with tail wagging were preferred
before short periods without tail wagging. The behaviours analysed for every episode can be
seen in Table 1.
Dog is with owner; DO1, DO2, DO3
Whining, grunting, barking, orienting at door, orienting at owner, moving, change position,
tail wagging.
Threatening stranger, owner present: DOtS
Whining, grunting, barking, orienting at door, orienting at owner, orienting at stranger,
moving, change position, tail wagging, approach and avoidance.
Separation; D1, D2
Whining, barking, grunting, orienting at door, moving, position change and tail wagging
Threatening stranger during separation: DtS
Whining, grunting, barking, orienting at door, orienting at stranger, moving, change position,
tail wagging, approach and avoidance.
Reunion; RU
Whining, grunting, barking , orienting at door, orienting at owner, moving, change position,
tail wagging, approach, avoidance.
Friendly stranger; DOfS
Whining, barking, grunting, orienting at stranger, orienting at owner, orienting at door,
moving, position change, tail wagging, approach, avoidance.
Table 1: Variables that were measured during the episodes (duration measured in seconds).
Behavioural categories for reactive dogs in this test were either barking or grunting at the
stranger. Non-reactive dogs showed either no such behaviour directed to the stranger or in
two cases dogs vocalised (high pitched barking and whining) only during the tS orienting at
the door instead of the stranger, and they showed similar behaviour during the separation
before (D1) and after (D2) this episode as well.
5. Experiment II
In this experiment the behavioural and hormonal response of dogs to separation and the
approach of a threatening human were investigated. One important difference in the
procedure between experiment I and II is that here the dog was not expected to be
sit/stand/lay relatively motionless during the test and it is performed outdoors. They could be
threatened more intensively so the threatening was made longer, three minutes instead of one
as in the 1B) and the stranger here was a man.
5.1 Methods
A pilot study was performed with a beginner’s class at a dog school in the early spring. 18
dogs (10 males, 8 females of different sizes, breeds and ages) participated. The breeds were
two Labrador Retrivers, one Border Collie, one Bichon Frisé, one Boxer, one Cane Corso,
one Collie, one English Cocker Spaniel, one Fox Terrier, one Germen Shepherd, one Golden
Retriver, one Hungarian Vizsla, one Minuature Schnauzer, one Mudi, one Pug and three
mixed breeds. Following the protocol of a previous test one experimenter was holding the
dog on a leash during the threatening approaches in order to ensure it is still on the starting
point when the stranger starts. The three groups were balanced for gender, size, age and
breeds. The threatening stranger was a woman (Vas et.al.). (For the detailed protocol of the
procedure see below.)
1. Separation
Dog is alone for a minute and can not see the owner.
2. Separation + Threatening approach
The owner hides and an experimenter hold the dog in a leash to ensure that the dog keeps
attention to the stranger when the approach starts. The threatening continues until the stranger
is almost in physical contact or until the dog intensively tries to escape.
3 Threatening approach
The owner stands so the dog just can’t reach him/her and the dog is on leash by an
experimenter. The threatening continues until the stranger is almost in physical contact or
until the dog intensively tries to escape.
The behavioural data followed the expectations but the result of the cortisol samples didn’t
show any significant changes so we changed the female stranger to a male and the
experimenter who was holding the leash was excluded, then it is showed that a friendly or
neutral unfamiliar person may have a calming effect in dogs in a stressful environment. The
approach of the stranger was made longer to increase the affect of threatening. The duration
of the separation episode was changed to 3 minutes.
Field test
Equipment
The saliva was taken from the inside of the lips with cotton paper and was put in a Eppendorf
tube and storded in a box with dry ice, temp -80º Celsius, until it was analysed. After
rendering to room temperature the cotton roll was placed into a centrifuge (Ultrafree®-MC
Centrifugal Filter Units with UF Membrane). Recovering of saliva at 10’, 1500 rpm.
Measuring of hormone level by competitive ELISA method (EIA kit, Salimetrics LLC, Inc.,
State College, Pa.)
Subjects
28 dogs from dog schools were used. They were six Germen Shepherds, three Airedel
Terriers, two Border Collies, two Bullmastiffs, two Golden Retrievers, two Hungarian
Viszlas, one American Staffordsgire Bullterrrier, one Belgian Shepherd, one Boxer, one
Dutch Shepherd, one English Cocker Spaniel, one Mudi, one Japanese Spitz, one Leonberger,
one Standard Schnauzer, one Pumi and one Mongrel. The samples were balanced for age,
gender, breed, training experience and size.
Procedure
The test was run at a familiar environment, in the park near the dog school.
Sample taking 1 – First the experimenter greeted the dog, petted it and took a saliva
sample from the inside of the lips to get the dogs` cortisol baseline. In case of aggressive or
fearful dogs, the owner took the cortisol sample. The greeting and sample taking was
recorded.
During the test the dogs were kept in a two meter long leash that was tied to a tree.
Right in front of the tree twelve meters away was a big rock where the stranger and owner
could hide. The camera man was standing next to the rock during the experiment. The dogs
only participated in one of the trials.
1. Separation (SEP) – The owner is standing next to the dog and the cameraman signals to
him/her to leave the dog and hide behind the rock. Three minutes later the cameraman tells
the owner to go back and greet the dog.
2. Threatening stranger, owner present (TO) – The owner stands two meters from the tree,
just so the dog can reach him/her (them). The owner is quiet and not moving during the test.
The threatening stranger, who was hidden behind the rock, approaches the dog very slowly
while gazing at it. If the dog is looking in another direction, the stranger could make some
noises to get the attention again. The threatening approach continues until the stranger is
close enough to pet the dog or if the dog tries to escape, but never longer than three minutes.
Then the stranger greets the dog in a friendly way calling it by its name and tries to pet it for
three seconds. If the dog refuses to come, the stranger tries to go nearer and pet it.
3. Threatening stranger, in separation (TS) – The owner leaves the dog at the tree and hides
behind the rock. The threatening approach is performed exactly as in the TO, explained
above. Afterwards the owner comes and greets the dog.
After the test the owner takes the dog for a short walk and tries to avoid intensive interactions
or play with other dogs for 25 minutes.
Sample taking 2 - 25 minutes after the test, the second cortisol sample is taken. This
sample taking is not recorded. Variables and scores for analysed behaviours can be seen in
Table 2.
ABBR.
VARIABLE
Greeting
AGR
Aggressio
n
FEA
Fear from
the Exp.
REA
reaction
for
approach
tail wag
WAG
Sample Taking
STR Struggling
DEFINITION
Type
0 - no aggression during the greeting
1 - growl, grunt, bark starting with a grunt
2 – snarl, attack, snap
0 - no sign of fear during the greeting
1 - any sign of fear during the greeting
fear: tail between legs, retreat, whining, hiding behind
owner
0 – show avoidance
1 – neutral – no movements
2 – show approach /stand at tight leash
tail wagging
score
(0-2)
reaction for sample taking:
0 – dog sit/stand calmly
1 – dog struggles (active moving/backing) more than 5 s
Threatening Approach
RE1
reaction
First reaction (when the Exp. starts the approach)
for
0 – show avoidance
approach
1 – neutral – no movements
1
2 – show approach /stand at tight leash
RE2
reaction
Final reaction (Exp. is closer than 2 m from dog)
for
0 – show avoidance
approach
1 – neutral – no movements (or just sniffing around)
2
2 – show approach /stand at tight leash
WAT tail wag
tail wagging during the threatening approach
score
(0-1)
score
(0-2)
score
(0-1)
score
(0-1)
score
(0-2)
score
(0-2)
score
(0-1)
GRO
Growl
Relative duration of growling, grunting
%
BAR
Bark
Relative duration of barking
%
WHI
whining
Relative duration of whining
%
ORO
orient to O Orientation to owner’s face during the whole test
APO
approach
of Owner
APF
Approach
FS
WAF
tail
wagging
GBF
Grunt/bar
k of FS
Separation
STS
Stress
Approach: if the dog get closer to the owner than its body
length during the whole test
Approach of the friendly Exp. till physical contact
Tail wagging during the friendly approach
Grunting, growling, barking at the friendly stranger
Duration of responses related to stress: tear about, tense
leash + barking, whining, grunting
Score
0-1
score
0-1
score
0-1
score
0-1
score
0-1
S
Table 2: Variables for the analysed behaviours
6. Results
6.1 Test I A - Cortisol level during separation and harness put on
Cortisol sample was taken three times: 1) “arrival” (measuring environmental stimuli that
was not under control); 2) baseline (measuring partly stimuli related to arrival, but mainly
during awaiting in an empty room together with owner who filled in a questionnaire); 3) after
harness was put on during separation or with owner (looking for the effect of separation and
the handling of a friendly stranger).
All cortisol data had a normal distribution tested with one-sample KolmogorovSmirnov test, so parametric statistics was used in all cases.
When samples 1 and 2 were compared no difference was found in cortisol levels of the
whole sample analysed together using paired t test (t(29)= -0.44; p=0.666).
In order to look for the effect of separation the samples 2 and 3 of the dogs were compared.
Analysed with repeated measures ANOVA no effect was found of group (separated vs tested
with owner) (F(1)=2.28; p=0.142). Note the rather high variability in the cortisol levels (Fig.
8). There were also no effect of putting on the harness (F(1)=0.32; p=0.579), and the
interaction as well (F(1)=0.25; p=0.624). This means that the absence of the owner did not
influence the cortisol level of the dogs in the separated group.
Cortisol level of dogs before (1, 2) and after (3) harness put on
0,180
cort1
cort2
cort3
Cortisol in ug/dl (mean+SE)
0,160
0,140
0,120
0,100
0,080
0,060
0,040
0,020
0,000
With owner (N=15)
Separated (N=15)
Fig. 8. Cortisol levels before and after the harness put on in the “with owner”- group
and “separated” group.
6.2. Test 1B - Behavioural and heart rate response during separation
In order to study the predicted manifestation of the “secure base” effect of the owner during
the threatening approach the effect of separation was first analysed per se both on the
behaviour and the heart rate of the dogs. The effect of the separation was measured on the
behaviour using the data on the distress vocalisation of the dogs. To make comparison
possible the sample was divided into two groups. “Reactive” individuals showed distress
vocalisation (whining, barking or both) during the separation episode, and “non-reactive”
individuals did not do so (Fig. 9).
Distress vocalisation during separation
Reactive
B order (N=16)
Number of individuals
16
Non-reactive
A order (N=14)
14
12
10
8
6
4
2
0
Sep 1 - Before
threatening
appr. with owner
Sep 2
Sep 1 - After
threatening
appr. with owner
Sep 2
Figure 9. Number of individuals who were reactive and non reactive to
separation in the two orders.
The changes of the dogs’ cardiac responses were analysed with ANOVA for repeated
measures. The possible relationship of heart rate and separational distress was analysed and
the level of the heart rate during the episode preceding the separation (dog with owner) was
compared with the first separational episode in both orders (Fig. 10).
No effect of separation (F(1)=2.28; p=0.142), reactivity (F(1)= 0.558; p=0.462) and order (F(1)=
0.101; p=0. 753) was revealed and there were not significant interactions as well.
heart rate response to separation
100
hearrt rate beat/minute
90
80
70
60
dog with owner
50
separation
40
30
20
10
0
non reactive (N=16)
reactive (N=14)
Fig 10. Heart rate response (mean + SE) to separation for the reactive group and the non
reactive group.
Corridor separation
As no effect of the separation on the heart rate level was found in the pilot study a more
“live” situation for separation was designed in which the prediction was to evoke increased
distress. To analyse the effect of the “corridor” separation the same behavioural variables
(distress vocalisation) was used to divide the dogs into “reactive” and “non-reactive”
individuals. Only 6 dogs out of the 23 did not show distress vocalisation during this
separation. Some data could not be used because of to many movements of the dogs during
the test.
Although the subjects indeed had an increased behavioural response, again there was no
effect of the separation on the heart rate level of the dogs (Fig. 11). The repeated measure
Anova revealed no effect of separation (F(1)=0.00; p=0.99), group (F(1)=1.525; p=0.23) and
most importantly no effect of interaction between group (reactivity) and separation
(F(1)=5.32; p=0.474). So those subjects who whined/barked more during the separation did
not have an increased level of heart rate.
Heart rate in beat/min. (mean +SE)
Heart rate measured during the
"corridor" separation
with owner
separated
110
100
90
80
70
60
50
40
30
20
10
0
Non-reactive (N=6)
Reactive (N=17)
Fig. 11.Heart rate response to separation for reactive and non reactive dogs.
1B – Behavioural and heart rate response during the threatening approach
All heart rate data had a normal distribution tested with one-sample Kolmogorov-Smirnov
test, so parametric statistics was used in all cases.
Dogs that grunted, growled or barked during the threatening approach of the stranger
were categorised as “reactive” and those showing no such behaviours were labelled as “nonreactive” ones (Fig 12). The heart rate responses for both the orders are present on a group
level in Fig. 13 and 14.
The rate of reactive subjects during the
threatening approach in the two situations
Non-reactive
Number of individuals
30
Reactive
25
20
15
10
5
0
Separated
With Owner
Fig.12. Number of dogs reactive to threatening approach when owner was present or
absent. Behaviour data from both orders are summed.
heart rate level of dogs (B order, N=16)
140
heart rate beat/minute (mean + SE)
heart rate, beat/minute (mean + SE)
heart rate level of dogs (A order, N=14)
120
100
80
60
40
20
0
140
120
100
80
60
40
20
0
DO1
DOtS
DO2
D1
DtS
D2
RU
DO3
DOfS
DO1
Fig. 13. A order, the first threatening–
owner present.
D1
DtS
D2
RU
DO2
DOtS
DO3
DOfS
Fig. 14. B order, the first threatening–
during separation.
The effect of the two types of threatening approaches (with owner or separated) were
analysed and compared with the heart rate in the episodes involving the threatening
approaches with both the preceding and following episodes (DO-DOtS-DO and D-DtS-D).
Grouping was made by the reactivity of dogs for the threatening stranger (Fig. 15 and 16).
Two way repeated ANOVA (threatening approach and owner presence) revealed
significant effect of stressor stimuli (threatening approach) (F(2)=15.27; p<0.001).
Significant effect of interaction group x threatening approach (F(2)= 9.53; p<0.001), so those
dogs that grunted/barked during the threatening approaches had also higher heart rate level in
those episodes.
No effect of the owner (F(1)= 0.502; p<0.485), group (F(1)= 3.349; p<0.079), order
(F(1)=0.932; p<0.343) and reactivity x order interaction (F(1)= 0.345; p<0.562) or in the other
interactions was found.
A significant difference of interaction of owner x threatening approach could be
revealed (F(2)=4.448; p<0.016), providing evidence that the approach of the threatening
stranger evoked less response in the dogs’ heart rate level in the presence of the owner than
when facing the same situation in separation.
heart rate beat/minute (mean + SE)
Heart rate levels of the ractive and non reactive dogs in the A
group
reactive
non reactive
160
140
120
100
80
60
40
20
0
DO1
DOtS
DO2
D1
DtS
D2
RU
DO3 DOfS
Fig.15. Heart rate (mean + SE) response in the two groups identified by their
behavioural response to the threatening approach. (Reactive dogs N= 8. Non reactive
N=6.)
Heart rate level of reactive and non reactive dogs in the B
group.
heart rate beat/minute (mean + SE)
reactive
non reactive
160
140
120
100
80
60
40
20
0
DO1
D1
DtS
D2
RU
DO2
DOtS
DO3 DOfS
Fig.16. Heart rate (mean + SE) response in the two groups identified by their
behavioural response to the threatening approach. (Reactive dogs N=9. Non
reactive N=7)
7. Result II
All behavioural and cortisol data had a normal distribution tested with one-sample
Kolmogorov-Smirnov test, so parametric statistics are used in all cases.
Behavioural analysis
During the separation seven out of the nine dogs whined, barked or jumped orienting towards
the hideout of the owner. Also seven dogs were grunted/barked and oriented at the stranger
during the threatening approach both in the group tested with (N=9) and without (N=10) the
owner.
Comparing the relative duration of these behavioural responses by one way ANOVA no
significant differences was found among the three groups (F(2)=0.791; p<0.464).
Four of the seven reactive (barking/grunting) dogs in the TS group showed avoidance during
the approach, that is they tried to run away pulling the leash to the opposite direction to the
stranger. Among the TO dogs, however, only one dog showed similar behaviour. Actually
four dogs spent most of the time in close contact of the owner that is instead of trying to get
off the stranger as much as they could, they moved sideward to the owner and stuck there
(Fig.17).
Fig. 17. Characteristic position of
dogs threatened when owner is
present.
Analysis of cortisol data
The cortisol data of the three groups was analysed using a two-way repeated ANOVA.
Saliva cortisol ug/dl (mean+SE)
Cortisol response of the 3 groups
Before (1. sample)
0,12
After (2. sample)
0,1
0,08
0,06
0,04
0,02
0
Separation
(N=9)
Threatened
with Owner
(N=9)
Threatened in
Separation
(N=10)
No significant effect was found of the stress stimuli (F(1)=0.380; p<0.543) and the group
(F(1)=0.401; p<0.674) when the cortisol levels were compared. Most importantly also no
effect of interaction (F(2)=0.076; p<0.927) was revealed between the stressor (change in
cortisol level) and the group (type of stimuli used). This means that in spite of the
characteristic behavioural responses referring to stress or even aggression, neither of the
stimuli had an effect on the cortisol level of the dogs.
8 Discussion
The aim of the study was to find physiological parameters as heart rate- and cortisol changes
to define stress in family dogs according to their behaviors. This area is still new and more
methods should be evalutaded to develop more and well working procedures for further
studies. Some behaviours could maybe involve different kinds of physiological stress
indicators and some kind of behaviours could maybe have a bigger correlation to physical
reaktions.
8.1 The effect of separation
Separation from the owner in this kind of stress situation did not seem to have any affect on
the cortisol or the heart rate. It could be because the separation was not long enough to have
an effect on the cortisol level or the unfamiliar experimenters in the room could have an
calming effect on the dog (Tuber et al. 1996). It could also be because of well socilaised dogs
who where used to be handled by unfamiliar humans or they were used to shorter separations
in their daily life. Differneces in the separated and non separated groups when the harness
was put on was investigated but this stimulus did not seem to be threatening enought to show
any cortisol increse. If the dogs also did not have any problem with the separation there was
nothing in this test that was given enough stimuli for a cortisol increse. It could be the case
that cortisol is not a good indicator of separational stress and should not be used in cases like
this. The first sample was taken without knowing what had happpende to the dog before it
arrived to the department. It was just for info but apparently did not show any difference from
the samples taken after rest or stimuli. A suggestion is that cortisol should be used where the
behaviours and the happenings around could be controlled and noted. Our results correlates
well with Hypothesis 1 – Experiment 1A and Experiment 2: H0: Dogs’ cortisol level does not
change after a separation from the owner in an unfamiliar environment. Also Hypothesis 3 –
Experiment 1B: H0: Dogs’ heart rate is not affected by separation from the owner in an
unfamiliar environment. Cortisol and heart rate maybe should have a more “aktive” stimuli
than separation. It could possibly have a bigger effect in a high stressfull environment.
8.2 The effect of the threatening stranger
In both the orders in the test 1B we could find dogs that were behaviourally reactive and non
reactive for threatening approach. The reactive dogs showed a higher heart rate increase than
the non reactive. This correlates with Hypothesis 4 – Experiment 1B: H2: Dogs’ heart rate
will increase during the threatening approach depending on their behaviour during the
approach. If threat reactive dogs were separated from the non reactive dogs we could even
see a tendency for a secure base effect and agree on the Hypothesis 5 – Experiment 1B: H1:
The presence of the owner lessens the increase in the dogs’ heart rate level during the
threatening approach. The threatening approach where the owner was present had a lower
heart rate increase compared to the episode where the owner was absent. This could not be
seen in the group of non reactive dogs because they did not seem to be enough effected of the
threatening and because of that did not differ if the owner was there or not. In the B order, the
dogs had the two stimuli, separation and the stranger present for the first time, at the same
time. For the reactive dogs in the B order, the average heart rate during the threatening
approach during separation was the highest average value measured for all the episodes in
both A and B order. This could indicate not just that the owner presence/absence but also the
order of the threatening approach is of importance. This could maybe also explain the results
from the A order where the second threatening approach is almost as high as the first. In the
first approach it is a novel, and for some dogs a fearful situation, and the second time the dog
is without the owner but it is not now a novel situation. The statistical analysis indicates that
in the reactive dogs one can find an order effect in the heart rate changes according to the
threatening approach.
In the A order, the dogs are facing the stranger for the first time with the owner present
and for the non reactive dogs a decrease in the heart rate can be seen compared to the dogowner episode (DO1 and DO2). According to Graham and Clifton, (1966) orientation to
novel but not threatening stimuli would decrease heart rate in contrast to intensive threatening
stimuli that would make an increase (Maros et al. 2007 in press). If the dog was orienting to
the stranger without finding it as a threat this could have an effect on the heart rate and
decrease it. Heart rate decrease during threatening approach might be explained with that the
dogs are much socialised and used to unfamiliar humans with unfriendly behaviours or that
they themselves could be of very friendly nature against humans. (The highest heart rate in
this group is found in the reunion phase and suggest that those dogs is more affected of the
separation from the owner than from the threatening approach of a stranger.) In the next
threatening approach the owner is absent but the heart rate is almost exactly the same.
In the cortisol level of the dogs, nothing could be found even though these dogs were
threatend more intensive (because they were aloud to move) and for a longer time. Three
minutes compared to the 1B test dogs who only were threatened for one minute. This
correlates with Hypothesis 2 – Experiment 2:H0: The (change in) dogs’cortisol level is not
affected by the presence or absence of the owner when a threatening stranger approaches the
dog in an unfamiliar environment. According to the lack of cortisol increse in this test a
suggestion is that a threatening approach, where the stranger is only gazing at the dog, is not
enought to get an cortisol increse in normal pet dogs.
6.3 General discussion
The secure-base effect is a central feature of the attachment model promoted by Bowlby
(1972) and Ainsworth et al. (1969). Although observational studies on dog-owner behaviour
in the Strange Situation Test provided some support for an attachment relationship, the secure
base effect was only indirectly supported (Topál et al. 2005, Prato-Provide et al. 2003).
One could assume that the magnitude of the secure base effect depends on how stressful the
situation is perceived by the participant. Thus in order to collect more evidence for the
presence of a secure base effect in dog-human attachment relationship the dogs were exposed
to a threatening stranger (Vas et al. 2005).
In accordance to earlier studies (Vas et al. 2005) dogs differed in their response to the
stranger, which provided a basis for categorisation. “Reactive” dogs expressed various
vocalisations toward the stranger, in contrast to “non-reactive” dogs which did not change
their behaviour as a consequence of the stranger’s threatening approach. Importantly, this
behavioural difference was paralleled with changes in heart rate, that is, reactive dogs showed
a higher heart rate when approached by a threatening stranger. So far heart rate reactivity in
dogs was measured mainly in the case of non-social situations when the dog was frightened
by various stimuli (e.g. Beerda et al. 1998). Recently, however Palestrini et al. (2003)
reported that dog’s heart rate increased during separation from the owner despite decreasing
physical activity. This suggested that reacted with increased stress to separation from the
caretaker. The findings in this study did not provide support for this observation because dogs
separated from their owner did not change the heart rate despite behavioural indications of
experiencing stress. Variations in the behavioural and possibly physiological reaction to
separation from group members (in this case the owner) could be explained by difference in
socialisation in general and by experience of similar situations (separation from the owner at
novel places) in particular. This effect could also be found in the sample with regard to the
threatening stranger. Only about the half of the dog population (taken the two groups
together) was found to be reactive to an approaching threatening stranger. This means that
whether any stimulation within the “normal” range has an effect on the population level in
dogs depends crucially on the composition (and probably on the origin) of the population. In
the case with this study, the contribution of the reactive dogs was enough in both groups to
result in a group-level increase of the heart rate but the individual analysis of the data reveals
clearly that only a part of the dogs is affected. This could have been also the case in Palestrini
et al. (2003) although no individual data were provided.
Detailed comparisons of the results suggest that presence of a secure base effect with
regard to the changes in heart rate. This was more evident when comparing the “reactive”
dogs in the two groups where there was a clear difference in their reaction toward the
threatening stranger whom they met for the first time. Heart rate increased to a lesser degree
in dogs whose owner was present at this first encounter. This suggests that the presence of the
owner could provide a buffer against stress in dogs. Moreover this situation reduces also the
effect of a subsequent encounter with the same stranger when the owner is not present. In
contrast, in the absence of the owners reactive dogs experience high levels of stress
(suggested by the high heart rate frequency) which however habituates (decreases) when at
the next occasion the owner is present. These results support earlier finding where both dogs
and humans provide social support for each other in stressful situations (Wilson et al. 1991;
Odentaal and Meintjes, 2003).
It was somewhat surprising to find that stressful stimulation did not influenced the
cortisol levels. Although, there are reports showing that in particular situations dogs display
elevated levels of cortisol after stimulation, the results are not uniform. In these experiments
acute stress was generated by various stimuli such as strong noise, electric shock, flopped bag
(Beerda et al. 1997), thunderstorm (Dreschel and Granger, 2005), separation (Hennessy et al.
1997; Tuber et al. 1996), frightening objects (e.g. umbrella; Beerda et al. 1998a; King et al.
2003), and transport (Bergeron et al. 2002). However it seems that the stress response might
depend on both internal and external factors. Thus in this study, the separation from the
owner was probably not stressful under the given circumstances in this population of dogs.
Nevertheless this does not mean that separation in general has not such an effect because long
term separation form owners was shown to result in elevated levels of cortisol in shelter dogs
(Henessy et al. 1997).
In summary, one important lesson from this research is that if one investigates the dogs’
response to various environmental stimulation then one should not expect always a strong
group level effect which is based on a unified response. Instead, the dogs’ reaction varies at
the individual level which can be explained by both genetic and environmental factors. This
means that future studies should take into account the individual variation among dogs that
are related to personality (e.g. Svartberg 2005; Taylor and Mills 2007).
9. Acknowledgement
I am grateful to my supervisors Ádám Miklósi and Márta Gácsi. To Katalin Maros and
Tamás Faragó who has given a lot of help with heart rate measuring and to Zsuzsanna
Horváth for helping me with the cortisol measurments. To Per Jensen who has been the
Swedish contact and who helped me to find the project. A special thank to the persons acting
as threathening strangers during the many tests and finally to all the dog owners and their
dogs that participated as volounteers.
10. References
Ainsworth, M. D. S., & Wittig, B. A. (1969). Attachment and exploratory behaviour of oneyear olds in a strange situation. In B. M. Foss (Ed.), Determinants of infant behavior (Vo1. 4,
pp. 111-136). London: Methuen.
Beerda B, Schilder, MBH, van Hoof JARAM, de Vries HW, Mol JA. Behavioural, saliva
cortisol and heart rate responses to different types of stimuli in dogs. Appl Anim Behav Sci
1998;58:365-81.
Ben-Michael, J. (1995 September) The perception of undesirable behaviour in dogs. Paper
presented at Animals, health and quality of life. Seventh International Conference on Human
Animal Interactions, Geneva, Switzerland.
Bowlby, J. (1972). Attachment. Middlesex, England: Penguin
Books.
Cmic, L. S., Reite, M. L., & Shucard, D. W. (1982). Animal models of
human behavior: Their application to the study of attachment. In R. N.
Emde & R. J. Harmon (Eds.), The development of attachment and
a~liative systems. New York: Plenum.
Fox, M. W. (1968). Abnormal behavior in animals. Philadelphia: Saunders.
Fox, M. W. (1975) Pet-owner relations. In: Pet animals and society, ed. R. S. Anderson, pp.
37-52. Tindall, London,
Gácsi, M., Topál, J., Miklósi, Á., Dóka, A. & Csányi, V. (2001) Attachment behaviour of
adult dogs (Canis familiaris) living at rescue centres: Forming new bonds. Journal of
Comparative Psychology 115:423-431.
Láng E, Bánhidi L, Antalovits M, Izsó L, MitsányiA, Zsuffa A, Magyar Z, Horváth Gy,
Slezsák I, Majoros A, Dombi I, Molnár L. A complex psychophysiological method to assess
environmental effects (temperature, illumination, sound) on objective and subjective
parameters of humans in simulated work setting. In: Bánhidi L, Farkas J. ”Healthy
Buildings’94”. Proceedings of the 3rd International Conference (Budapest, Hungary, 2225August) 1994;2:799-803.
Láng E, Horváth Gy. Integrated System for Ambulatory Cardio-respiratory data acquisition
and Spectral analysis(ISAX) User’s manual 1994 Budapest.
Marston, L. C., Bennett, P. C. & Coleman, G. J. (2005) Factors affecting the formation of a
canine-human bond. IWDBA Conference Proceedings pp. 132-138.
Odentaal, J.S., Meintjes, R.A. 2003. Neurophysiological correlates of affiliative behaviour
between humans and dogs. Vet J., 165, 296-301.
Overall, K. L. (2000) Natural animal model of human psychiatric conditions: Assessment of
mechanism and validity. Progress in Neuro-Psychopharmacology and Biological Psychiatry
24:727-776.
Prato-Previde, E., Custance, D. M., Spiezio, C. & Sabatini, F. (2003) Is the dog-human
relationship an attachment bond? An observational study using Ainsworth's strange situation.
Behaviour 140:225-254.
Rajecki, D. W., Lamb, M. E., & Obmascher, P. (1978). Toward a general theory of infantile
attachment: A Comparatve review of aspects of the social bond. Behavioral and Brain
Sciences, 3, 417-464.
Serpell, J. A. (1996). Evidence for an association between pet behavior and owner attachment
level. Applied Animal Behaviour Science, 47, 49-60.
Svartberg K (2005). A comparison of behaviour in test and in everyday life: evidence of three
consistent boldness-related personality traits in dogs. Applied Animal Behaviour Science, 91,
103–128.
Taylor, K, D, Mills D S (2007). The development and assessment of temperament tests for
adult companion dogs. Journal of veterinary behaviour. Clinical Applications and Research,
1, 94-108.
Topál, J. Gácsi, M., Miklósi, Á., Virányi, Zs., Kubinyi, E. & Csányi, V. (2005) The effect of
domestication and socialization on attachment to human: a comparative study on hand reared
wolves and differently socialized dog puppies. Animal Behaviour 70:1367-1375.
Topál, J., Miklósi, Á., Csányi, V., & Dóka, A. (1998). Attachment behavior in dogs (Canis
familiaris): A new application of Ainsworth's (1969) Strange Situation Test. Journal of
Comparative Psychology, 112, 219-229.
Tuber, D. S, Henessey, M. B., Sanders, S., & Miller, J. A. (1996). Behavioral and
glucocorticoid responses of adult domestic dogs (Canis familiaris) to companionship and
social separation. Journal of Comparative Psychology, 110, 103-108.
Vas, J. Topál, M. Gácsi, Á. Miklósi, V. Csányi (2005) A friend or an enemy? Dogs’ reaction
to an unfamiliar person showing behavioural cues of threat and friendliness at different times.
Applied Animal Behaviour Science 94: 99–115
Wilson, C.C. 1991. The pet as an anxiolytic intervention. J. of Nervous and Mental Disease,
179, 482-489.
1 Abstract 5
2 Introduction
5
2.1 Background
5
2.2 Aims of the project and experimental hypothesis 7
2.3 Advantages of using physiological parameters
6
Saliva cortisol
Error! Bookmark not defined.
Hart rate
Error! Bookmark not defined.
3 Methods 7
3.1 Measuring heart rate 7
3.2 Measuring saliva cortisol
8
4 Experiment I
9
4.1 Materials and methods 9
Procedure - Experiment 1/A
9
Experiment 1/B
9
4.2 Result 16
A – cortisol level during separation and harness putting on
16
B – Behavioural and hart rate response during separation
17
B – Behavioural and hart rate response during the threatening approach
5 Experiment II
Error! Bookmark not defined.
5.1 Methods 13
5.2 Result 21
Behavioural analysis
21
Analysis of cortisol data 22
6 Discussion 22
6.1 Separation
22
6.2 The effect of the threatening stranger
23
6.3 General discussion
24
References 25
19