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Author info: Correspondence should be sent to: Dr. John Somervill, Baker 322,
Dept. of Psychology, U. of Northern Iowa, Cedar Falls, IA 50614
E-mail: john.somervill@uni.edu
North American Journal of Psychology, 2009, Vol. 11, No. 1, 111-120.
© NAJP
Handling a Dog by Children with Attention-
Deficit/Hyperactivity Disorder:
Calming or Exciting?
John W. Somervill, Ashley M. Swanson, Renee L.
Robertson, Marissa A. Arnett, Otto H. MacLin
University of Northern Iowa
Physiological reactions to handling a dog were recorded for 17 children
(13 males & 4 females ranging in age from 7 to 12 years), 16 with a
primary diagnosis of Attention Deficit Hyperactive Disorder. The major
finding was a significant increase in blood pressure and pulse rate five
minutes after holding a dog. It was concluded that a dog used for pet
therapy with children diagnosed as ADHD was more likely to have an
excitatory effect than a calming one.
Several studies have provided convincing evidence that pet
ownership, especially ownership of dogs, has significant long term
cardiovascular benefits (Friedmann, Katcher, Lynch, & Thomas, 1980;
Friedmann & Thomas, 1995; Friedmann, Thomas, Stein, & Kleiger,
2003) as well as other health benefits (Siegel, 1990). These findings have
led to an interest in the possible therapeutic benefits of introducing
animals in a variety of institutional settings.
Often, pet therapy occurs in an institution with relatively brief
exposure to an animal. Therefore, studies which assess participants’
reactions following brief exposure to an animal may be comparable to the
limited exposure times which often typify pet therapy programs.
Research on blood pressure and heart rate reactions to a dog have
studied participants from several different age groups. Vormbrock and
Grossberg (1988) found that among college students petting a dog
produced the lowest systolic blood pressure (SBP), diastolic blood
pressure (DBP), and mean arterial pressure (MAP). Talking to the dog
without physical contact produced higher SBP, DBP, and MAP, and
talking to the experimenter produced still higher SBP, DBP, and MAP.
Higher heart rates (HR) were obtained when participants were touching
the dog and when participants talked to the dog while touching it. Allen,
Blascovich, Tomaka and Kelsey (1991) studied adult female dog owners,
ranging in age from 27 to 55. Four physiological measures were used:
skin conductance response frequency (SCR), SBP, DBP, and pulse rate
112 NORTH AMERICAN JOURNAL OF PSYCHOLOGY
(PR). Participants in a condition involving the presence of a dog in the
room showed significant reductions in SCR, SBP, and PR when
performing stressful tasks (mental arithmetic) than participants in other
conditions. When participants performed the task in the presence of a
close female friend, they showed substantial physiological reactivity.
Generally, research with adults has indicated a reduction in
autonomic activation when a dog is present. However, Baun, Bergstrom,
Langston and Thomas (1984), using participants ranging in age from 24
to 74, reported an initial excitatory effect involving a significant increase
in both SBP and DBP when the participants’ own dogs were brought into
the testing room.
Blood pressure and heart rate reactions to a dog have been studied in
normal children who are inpatients in a hospital, as well as non-patients.
Friedman, Katcher, Thomas, Lynch and Messent (1983) studied the
effects of dogs during a mildly stressful situation on 9 to 16 year-old,
normal children’s SBP, DBP, MAT, and HR. A major finding was that
the presence of one of three friendly unfamiliar dogs resulted in
significantly lower MAP, SBP, DBP, and HR both while resting and
reading than when no dog was present.
Nagengast, Baun, Megel and Leibowitz (1997), in a study of normal
children between the ages of 3 and 6 years, reported a significant
decrease in MAP, HR, and SBP, during an experimental condition
involving a physical examination in which a dog (a beagle) was present,
compared to a control condition involving a physical examination in
which no dog was present. No significant difference in DBP was found
for the same comparison. Children with allergies to dogs, or an extreme
fear of dogs, and children with chronic conditions requiring frequent
doctor visits (more than three times per year) were excluded. A control
condition in which there was a physical examination with the dog absent
was compared with a similar physical examination with the dog present,
the order of which was counterbalanced. It was presumed that a physical
exam for children of this age constituted a stressful procedure. The
physical exam used a stethoscope, tongue blade and flashlight, otoscope,
neurological hammer, and ophthalmoscope.
Kaminski, Pellino and Wish (2002) studied 70 children, 5 years or
older who were inpatients at a large university hospital; 40 were in a
group in which the primary form of therapy was a variety of play
activities and 30 of the children were in a pet therapy group which
interacted with a pet one night a week. Children exposed to pet therapy
had a higher HR after the session with an animal than children following
a play therapy session with no animal. However, HR was not monitored
during the session in which children interacted with the animals.
Children in the pet group engaged in significantly more physical contact
Somervill, Swanson, Robertson, Arnett, & MacLin HANDLING DOG 113
with the animals than children in the play therapy group did with other
persons. Ratings of mood by parents and caretakers did not differ
between the play therapy and pet therapy groups. The authors suggested
that their finding of an increase in HR as opposed to other studies
reporting a decrease in physiological activity might have been due to the
fact that other studies involved efforts to increase stress prior to the
introduction of a pet.
Research with children on physiological responses to a dog has not
yielded consistent results. Children with behavior problems associated
with Attention-Deficit/Hyperactivity Disorder (ADHD) may react
differently to an unfamiliar animal than normal children. It is conceivable
that companion animals may have a calming effect on children with
ADHD. However, it is also possible that exposure to an unfamiliar
animal in children who tend to be excitable and over reactive may tend to
increase physiological arousal. The primary purpose of the present study
was to assess physiological reactions by children with a primary
diagnosis of ADHD to a friendly dog.
METHOD
The school from which children participated was a “level 3” special
education school which served 30 students in the 6 to 12-year-old age
group. The average duration of a student’s stay in this school was three to
four years. The longest a student could stay in this school is from
preschool (three-years-old) to 5th grade (14 years old). The primary goal
of the school is to facilitate the transition of students back to a classroom
in a regular school.
Participants
The principal of the school explained the research to parents
attending a parent/teacher conference and parents were given an
informed consent form. Parental permission was obtained for 22
children, 17 males and 5 females. Since the school served only 30
children in the age group studied, parental consent for 22 children
represented over two thirds of the available population. It is not known
how many parents failed to attend the parent /teacher conference or if any
parents in attendance refused to give their consent.
The study also was explained to each child for whom parental consent
was obtained and only children who gave their verbal consent
participated in the study. All 22 children gave their initial verbal consent;
however, five of the children did not complete all aspects of the study
and were excluded from data analysis for the following reasons: accurate
measurements could not be obtained for one male because of excessive
movement; a teacher took a second male back to the classroom prior to
114 NORTH AMERICAN JOURNAL OF PSYCHOLOGY
testing because of misbehavior; and the remaining three children did not
want to complete one or all three of the measurements taken on the day
in which no dog was present. None of the five children declined
participation on the test day in which the dog was present.
Of the 17 children for whom complete data were obtained, there were
13 males, ranging in age from 7 to 12 years (mean age = 9.31) and 4
females, ranging in age from 7 to 10 (mean age = 9.0). The mean age for
all children who had completed data was 9.24 years.
To preserve confidentiality, individual diagnostic labels were not
requested, but group diagnostic labels were provided for all 17
participants. The ethnic background of participants with completed data
included eleven Caucasians, four African Americans, and one child
described as bi-racial (one African American Parent and one Caucasian
parent).
Three of the four females were diagnosed as having Attention-
Deficit/Hyperactivity Disorder (ADHD). One of the three also had
additional diagnoses of Oppositional Defiant Disorder (ODD) and
Mental Retardation (MR) and another had an additional diagnosis of
ODD. The fourth female had a single diagnosis of ODD.
Complete diagnostic information was obtained for all 13 males. All
had a diagnosis of ADHD (8 of the 13 had a co-diagnosis of ODD, 1 had
a co-diagnosis of Depression, 1 had a co-diagnosis of Bipolar Disorder,
and 1 had a co-diagnosis of MR).
In summary, data analysis was based on 17 children, 16 with an
ADHD diagnosis as well as other co-diagnoses, and one with a single
diagnosis of ODD.
Measures
Teacher Ratings of Behavior. Teachers were asked to rate each child
on a five-point scale approximately one hour after a child returned from
each of two sessions, one with a dog present and one with no dog
present. Teachers were not told which session was with a dog or with no
dog. Five statements were rated on a five point scale where “1” was
strongly agree, and “5” was strongly disagree. The five statements were:
1) Child appeared to be happy and in a better mood than before the
research session, 2) Child appeared to be calmer and more at ease than
before the research session, 3) Child appeared to be more anxious and ill
at ease than before the research session, 4) Child seemed to be less
attentive than before the research session, and 5) Child seemed to be
more disruptive than before the research session.
Test sessions with children. Each child was tested for 15 minutes on
each of two test days. SBP, DBP, and HR were recorded at the end of
each 5-minute period during the 15 minute session. Children were taken
Somervill, Swanson, Robertson, Arnett, & MacLin HANDLING DOG 115
to a vacant school room by a female experimenter and were accompanied
by one member from the school staff. A dog was introduced during the
second 5-minute interval on one of the two test days. The dog was placed
on the child’s lap for five minutes and remained there until after SBP,
DBP and HR were recorded. Children were given no instructions
regarding how to interact with the dog. They were not discouraged from
petting the dog or talking to it except at the end of the five minute
interval when physiological measures were taken. The dog was then
removed from the room prior to the third 5-minute interval. The test day
with a dog was alternated with the test day with no dog. Children were
permitted to engage in conversations with the experimenter on both test
days and during all time intervals except during the recordings of SBP,
DBP, and HR.
Description of the Dog. The same dog was used for all participants.
The dog was a thirteen pound, four year-old blonde female Shi-Tzu
which had been examined by a veterinarian one week prior to the study.
The animal had no parasites or fleas and had all required shots, was non-
aggressive, and accustomed to being handled by many different persons.
Blood pressure and Heart Rate Recordings. SBP, DBP, and HR were
recorded using a Timex Automatic Upper Arm Blood Pressure Monitor.
For each measurement, the cuff was placed around the child’s right arm
with the bottom of the cuff approximately one inch above the elbow. In
most cases, the child pressed the “Start” button although it was
occasionally pushed by the examiner. The cuff automatically inflated and
subsequently, digital measures of SBP, DBP, and HR were displayed and
recorded.
Each child was asked if they have a dog currently, have ever owned a
dog, or have not had a dog. Out of the 17 participants, 6 have a dog
currently, 9 have had a dog, and 2 have never had a dog.
Of 17 children, therefore, 15 either currently have a dog or have had a
dog in the past. We did not record what happened to the dogs for the 9
children that once owned a dog. None of the children reported that their
dogs were or had been mean or aggressive.
RESULTS
A 2 (dog presence: dog day versus no dog day) by 3 (three
consecutive test sessions) repeated measures design was used to analyze
each of three dependent variables: SBP, DBP, and HR.
For the three ANOVAS, the main effect for dog presence approached
significance for SBP, F(1,16) = 4.217, p = .057, was significant for DBP,
F(1,16) = 4.863, p < .05, and was not significant for HR, F(1,16) =
0.952, p = .344.
116 NORTH AMERICAN JOURNAL OF PSYCHOLOGY
The main effect for the three time intervals was not significant for
SBP, F(2,32) = 1.551, p = .228; DBP, F(2,32) = 0.725, p = .492; or HR,
F(2,32) = .305, p = .739.
There was no significant interaction between the main effect for dog
present versus dog absent days and the main effect for the three 5-minute
time intervals for SBP, F(2,32) = .666, p = .52; DBP, F(2,32) = .54, p =
.59; or HR, F(2,32) = 2.04, p = .156.
Post hoc t-tests were used to compare the “dog present” day and the
“dog absent” day for each of the three 5-minute time intervals for SBP,
DBP, and HR. Post hoc t tests comparing baseline measures taken at the
end of the first time interval between “dog present” and “dog absent”
days were not significant for SBP, t(16) = 1.29; for DBP, t(16) = 0.47; or
HR, t(16) = 1.29.
Children held the dog in their laps for five minutes during the second
5-minute interval on the test day with the dog and simply interacted with
the experimenter during the second 5-minute interval on the test day with
no dog. Post hoc t-tests comparing measures taken after the second time
interval between “dog present” and “dog absent” days was not significant
for SBP, t(16) = 0.13; was significant for DBP, t(16) = 2.29, p<.05, SEM
3.46; and not significant for HR, t(16) = 1.21.
No dog was present during the third 5-minute interval for the test day
with a dog or the test day without a dog. Post hoc t-tests comparing
measures at the end of the third time interval for the test day with a dog
versus the test day with no dog, yielded a significant increase in SBP for
the test day with a dog, t(16) = 3.08, p < .01, SEM = 4.16; an increase in
DBP which approached significance for the test day with a dog, t(16) =
2.07, p = .055, SEM = 8.07; and a significant decrease in HR for the test
day with a dog, t(16) = 2.90, p <.01, SEM = 2.82.
In summary, DBP significantly increased while children held the dog
and SBP significantly increased during the interval that followed holding
the dog. However, HR significantly decreased during the interval that
followed holding the dog.
Teacher ratings for five behaviors. Teacher ratings on a five point
scale (1 = strongly agree and 5 = strongly disagree) were taken at the end
of each test day. T-tests were used to compare teacher ratings for dog and
no-dog days for each of the five statements about child behavior
mentioned in the Method section. None approached significance, and
only the first statement, “Child appeared to be happy and in a better
mood than before the research session”, yielded a t value higher or lower
than 1, t (16) = -1.17.
DISCUSSION
Previous research on pet therapy with both children and adults has
tended to emphasize the calming effects that companion animals,
Somervill, Swanson, Robertson, Arnett, & MacLin HANDLING DOG 117
particularly dogs, have on autonomic activity. Although there are
exceptions, most research has provided evidence that even brief exposure
to dogs tends to lower blood pressure. By contrast, the present study with
children whose primary diagnosis was ADHD resulted in a significant
increase in DBP while children held the dog and an increase in SBP
during the time period after holding the dog. The pattern for both SBP
and DBP was to increase while children held the dog in their laps as well
as to increase in the time period after holding the dog. However, the
pattern for HR was a decrease during both time periods. Almost all of the
children appeared enthusiastic when they found out that it was their day
to be with the dog. Hans Selye distinguished between physiological
changes associated with response to negative stimuli (distress) and
similar changes associated with response to positive stimuli
(eustress).We interpret the increase in blood pressure as indicating
eustress, a response to positive stimuli associated with handling a dog.
The decrease in HR during the same time periods is more difficult to
interpret. Increases or decreases in pulse do not invariably correspond to
increases or decreases in blood pressure, particularly in subgroups such
as individuals with closed head injuries. Decreases in pulse have also
been noted to occur while persons are orienting to a stimulus situation.
Conceivably, the decrease in pulse associated with handling a dog may
have involved a form of orienting behavior. Recall that measures of
blood pressure and pulse were taken simultaneously by an automatic
upper arm blood pressure monitor. Thus, the inverse relationship
between blood pressure and pulse did not involve a time difference
between blood pressure and pulse measures.
For children who have a diagnosis of ADHD, there is probably a
tendency by teachers to favor influences that are perceived as calming
rather than exciting. Such expressions as “calm down,” “don’t get
excited,” etc., primarily reflect our values as they relate to quietness and
inactivity in an educational environment. However, we can also
recognize that being happy, elated, or excited are positive aspects of our
emotional experience. Such may be the case when children are
enthusiastic about interacting with a friendly dog. In that sense, these
findings could actually indicate some positive consequences of pet
therapy with ADHD children.
Another aspect of this study was to assess whether there would be
any behavioral changes that might be detected by teachers on days when
children interacted with the dog. Based on teacher ratings, there were no
significant changes in any of these moods or behaviors.
Why did the findings of this study differ from a study by Nagengast
et al.(1997)? One explanation may be that in the present study, there was
no intentional manipulation of the stress variable. Children were simply
118 NORTH AMERICAN JOURNAL OF PSYCHOLOGY
taken from their classroom to another familiar room in the same building
while in the company of a staff member and the experimenter. Rather
than seeking to create a stressful situation, efforts were made to keep the
educational and physical environment constant and minimize any stress
that might be associated with the experimental situation. In the study by
Nagengast, et al., children were taken to an examining room and
intentional efforts were made to simulate a presumably stressful situation
involving a physical examination. It is conceivable that the physiological
baseline for their study was one of increased arousal whereas the baseline
in the present study was one of relatively low arousal.
A possible explanation for the findings with ADHD children is that
handling a friendly dog is associated with an initial and continuing
increase in blood pressure resulting from excitement. Since there were no
measures taken after the 15 minute test periods, it is not possible to
determine whether interacting with the dog was associated with a
sustained arousal beyond the experimental session. It is improbable that
physiological arousal related to handling of a dog was due to novelty
effects resulting from minimal prior contact with dogs, because most of
the children owned or had owned a dog.
One limitation of the present study was the lack of a control test
session consisting of some type of manipulation other than just the
absence of the dog. For example, a test day using a stuffed animal or
some other manipulation than simply a test day in which no dog was
present. As suggested by studies cited in the introduction, temporary
increases or decreases in both blood pressure and heart rate can occur as
a result of a variety of manipulations such as talking to the experimenter,
reading, solving a math problem, or the presence of a familiar person. In
the present study, the effects of the dog could not be isolated as the
specific cause of autonomic activation.
In summary, one possible interpretation of the results of the present
study is that the use of pet therapy with ADHD children may be a
positive experience associated with excitement. However, the absence of
a control group with an alternative manipulation limits this conclusion.
Regardless, there was no support for a possible assumption that
interactions with a friendly animal would have a calming effect on
ADHD children.
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